smcsyv - sociedad mexicana de ciencias, superficies y vacio viii...naboru takeuchi/cnyn-unam...

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VIIIInternational Conference on Surfaces, Materials andVacuumSeptember 21st – 25th, 2015 Puebla, Puebla

PROCEEDINGS

Sociedad Mexicana de Ciencia y Tecnología de Superficies y Materiales A.C.

VIII International Conference on Surfaces, Materials and Vacuum

September 21st – 25th, 2015 Puebla, Puebla

ORGANIZING

COMMITTEE

Juan Hernández Rosas UPIITA-IPN

Gregorio Hernández Cocoletzi IFUAP

Servando Aguirre Tostado CIMAV

Emmanuel Haro Poniatowski UAM-Iztapalapa

Leticia Pérez Arrieta UAZ

Cristo Manuel Yee Rendón UAS

Claudia Mendoza Barrera Microna-UV

LOCAL ORGANIZING

COMMITTEE

BUAP Gregorio Hernández Cocoletzi

Juan Francisco Rivas Silva Pedro Hugo Hernández Tejeda

Gerardo Martínez Montes

Ygnacio Martínez Laguna

Rosendo Lozada Morales

Martha Palomino Ovando

Jesús Carrillo López María de Lourdes Ruiz Peralta

Mirna López Fuentes

Dolores García Toral Heriberto Hernández Cocoletzi

José Humberto Camacho García

Ernesto Chigo Anota Alejandro Escobedo Morales

Mercedes Portillo Sampedro

INAOE Wilfrido Calleja Arriaga Arturo Sarmiento Reyes

Luis Hernàndez Martìnez Carlos Zuñiga Islas

Francisco Javier de la Hidalga Wade

UAEH Ariadna Sánchez Castillo Arturo Hernández Hernández

María del Pilar Gutiérrez Amador Efraín

Zaleta Alejandre Lis Tamayo Rivera

Víctor Hugo Pérez España

Teresa Romero Cortes Jaime Alioscha Cuervo Parra

Eduardo Rangel Cortes

Martin Peralta Gil Pablo Antonio López Pérez

INTERNATIONAL

SCIENTIFIC COMMITEE

Patricia Thiel AVS, USA

Ivan Petrov

AVS, USA

Arturo Morales Acevedo

CINVESTAV-IPN

Juan Luis Peña Chapa CINVESTAV-IPN

Steven Muhl

IM-UNAM

Alvaro Pulzara

Universidad Nacional de Colombia

José Mauricio López Romero CENAM

Jesús González Hernández

CIDESI

PROGRAM

COMMITTEE

Naboru Takeuchi/CNYN-UNAM

Gregorio Hernández Cocoletzi /IF-BUAP

Jesús Heiras Aguirre /CNYN-UNAM

Roberto Olayo/UAM-Iztapalapa

Roberto Machorro /CNYN-UNAM

Wilfrido Calleja/INAOE

Horacio Estrada Vázquez /CENAM

Máximo López /CINVESTAV-DF

Jaime Santoyo Salazar /CINVESTAV-DF

Cristo Manuel Yee Rendón /UAS

Citlali Sánchez Aké/CCADET-UNAM

Guillermo Santana/ IIM-UNAM

Sergio Jiménez /CINVESTAV-Qro

Salvador Gallardo Hernández /CINVESTAV-DF

L. Irais Vera Robles/UAM-Iztapalapa

Sandra Rodil (IIM-UNAM),

Giovanni Ramírez /Argonne National Laboratory

Joaquín Oseguera Peña /ITESM




Dear Colleagues,

From the very beginning the Annual Conference of the Sociedad Mexicana de Ciencia y

Tecnología de Superficies y Materiales (SMCTSM, Mexican Society of Science and

Technology of Surfaces and Materials) has been an important forum used by the Mexican

scientific community for the discussion of scientific and technological topics related to

research in the areas of surface and materials science. The SMCTSM is celebrating its 35th

anniversary and for this special occasion we are pleased to welcome you to participate in the

VIII International Conference on Surface, Materials and Vacuum (ICSMV) which will held

in the city of Puebla, Puebla from the 21st to the 25th of September.

This year will do the works of the confereces at the Edificio Carolino facilities, an

emblematic XVII building. For this anniversary the event is co-organized between the

Benemérita Universidad Autónoma de Puebla, and the Instituto Nacional de Astrofísica

Óptica y Electrónica.

The scientific program of the Conference is divided into plenary conferences, short courses

and the different symposia with oral and poster. For the VIII edition the symposiums of

Biomaterials and Polymers have merged and the same has occurred for the symposiums of

Photothermal and Plasma and Vacuum and we have an invited symposium of Atomic Layer

Deposition. Additionally to the scientific program, there is a symposium of Popularization

of Science which is a traditional forum for the bringing together of students and the general

public with the work undertaken and developed within our Society.

We hope that the efforts of the organizing committee, sponsors and colleagues will result in

an interesting friendly meeting, providing the opportunity for closer and new interactions

between researchers coming from the diverse institutions

VIII ICSMV Organizing Committee

SMCTSM

September 2015. Puebla, Puebla, México.




1

OPENING TALK

The 14-billion Year History of the Universe

Leading to Modern Materials Science

Joe Greene

D.B. Willett Professor of Materials Science and Physics, University of Illinois

Tage Erlander Professor of Physics, Linköping University, Sweden

University Professor of Materials Science, National Taiwan Univ. of Science and Technology

The story begins approximately 13.8 billion years ago with the Big Bang. A brief introduction will

trace the evolution of the universe to what we observe today. Many of the formative events occurred in the first

tiny fractions of a second (e.g., electrons, protons, and neutrons appear) to a few tens of thousands of years

(elementary particles react to form the first elements which leads, in turn, to the development of stars due to

local density fluctuations). Planet Earth nucleated and began to accrete interstellar debris ~4.5 billion years ago.

While the lighter metal elements on earth formed primarily due to stellar supernovae explosions, the primary

mechanism leading to the formation of the heavier elements has only recently been demonstrated. The first

known sophisticated stone tools used by huminids, found in northern Ethiopia, date to 2.6 million years ago

Gold is likely the first metal discovered by man, >11,000 years ago. However, unlike copper

(Mesopotamia, ~9000 BC), bronze (Iran, ~5000 BC), and cast iron (China, ~600 BC), it was too soft for

fabrication of tools and weapons. Instead, gold was used for decoration, religious artifacts, and commerce.

Spectacular metal sculpting displaying very high levels of metallurgical and artistic craftsmanship have been

found in Mesopotamia (S. Iraq). The earliest high-purity Au artifacts derive not from Egypt, as commonly

thought, but from NE Bulgaria ~6500 y ago; however, the largest known concentration of ancient gold mines

is in the Egyptian Eastern Desert. Metal extraction from ore, copper smelting, was already being carried out in

the Balkans (E. Serbia and S. Bulgaria) ~7500 years ago.

Gold brazing of metal parts was first reported in ~3400 BC in Sumaria. The earliest documented thin

metal films were gold layers, some less than 1000 atoms thick, produced chemi-mechanically by Egyptians

~5000 years ago. Examples, gilded on copper and bronze statues and artifacts (requiring interfacial adhesion

layers), were found in hewn stone pyramids dating to ~2650 BC in Saqqara. Spectacular samples of embossed

gold sheets date to at least 2600 BC. Electroless gold and silver plating was developed much later by the Moche

Indians of Peru in ~100 BC.

Gas-phase deposition of thin layers of metal and ceramic films on bulk substrates (as used in manufacturing of

today's transistors, hard discs, LED TVs, etc.) had to wait for the invention of vacuum pumps (~1650 for

mechanical pumps, similar to modern bicycle pumps, but with gas flow in the opposite direction) through

~1865. The fascinating development of crystallography (Plato [Greece], 360 BC; through Kepler [Germany],

1611; Haüy [France], 1780s; and Miller [UK, 1839]), was essential for describing crystal structure in modern

materials science, mineralogy, and geology.

While an historical road map tracing the progress of materials technology is interesting in itself, the

stories behind these developments are even more remarkable and provide insight into the evolution of scientific

reasoning.




2

INTERNATIONAL YEAR OF LIGTH

CELEBRATION TALK

Light and the refracting power of matter

Rubén Barrera.

Instituto de Física, Universidad Autónoma de México, México

In this talk I present an historical review of the development of one of the

main concepts in Optics: the index of refraction. I stress the physical ideas

behind this concept and also the contributions done in this issue during the

Golden Age of Islamic Science, as part of the celebration of the International

Year of Light 2015.




3

PLENARY 1

Electron Dynamics, Magnetic Impurities and the Spin-Orbit

Interaction in Graphene Systems

Sergio E. Ulloa

Department of Physics and Astronomy and

Nanoscale and Quantum Phenomena Institute

Ohio University

Graphene, a monoatomic layer of carbon, is perhaps the simplest and most easily

available material where electrons behave as massless Dirac particles. Apart from its

many promising technological applications, the study of graphene (and other layered

materials) has opened a number of interesting theoretical questions: the microscopic

crystalline structure requires an additional degree of freedom (the pseudo spin) that

gives rise to effects such as the Klein paradox or Veselago electron lenses.

This relativistic dynamics is further emphasized by the presence of an interesting

relativistic effect: the spin-orbit interaction (SOI), which is present in materials that

lack inversion symmetry in the lattice structure or arises from external or interfacial

fields that break spatial symmetries. Although SOI is weak in natural graphene, it can

be enhanced by local hybridizations with impurities by manipulation of substrates or

applied gates.

I will present our studies of electronic transport and Kondo screening in graphene

under realistic SOI and some of its experimental observables, including birefringence

in electron optics.




4

PLENARY 2

Design and Synthesis of Hard and Tough Coatings

Yip-Wah Chung

Department of Materials Science and Engineering and Mechanical Engineering

Institute for Sustainability and Energy

Northwestern University, Evanston, Illinois, USA

Most hard coatings are made of ceramic materials and have low toughness. It is desirable to

have coatings that are both hard and tough to provide superior wear performance. There are

many studies reported in the literature on obtaining hard and superhard coatings. This talk

will focus on strategies to increase coating toughness while maintaining hardness. Various

nanocomposite and multilayer coatings were synthesized to explore three such toughening

strategies: coherency strain, transformation toughening, and nanograined metals. Results

demonstrate that coating systems that exploit these strategies show significantly enhanced

toughness compared with those that do not. In particular, the strategy of using nanolayers of

a metal with high elastic modulus alternating with spacer layers much thinner than the metal

even reverses the commonly observed inverse hardness-toughness relationship. In principle,

one can reach hardness values up to 10% of the elastic modulus, while attaining toughness

comparable to most nanocrystalline metals.




5

PLENARY 3

Multiscale Biophysics: from DNA to antibodies. A synergetic approach

between SPM and HPC simulations.

Pedro A. Serena1, J.G. Vilhena1,2, Ruben Perez2

1 Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid , Spain

2 Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de

Madrid, Madrid, Spain

Biophysics is an intrinsically multiscale research field. Most of the large scale properties

(protein-folding, self-assembly, mechanical properties, wetting) of biological media heavily

depend on things that occur at atomic scale. As a result, in this field, until very recently there

was a huge gap between the processes studied in a lab and the ones that theoreticians could

provide a predictive-modeling input. The access to massive computational power allows the

study of systems composed by tens of millions of atoms over long periods of time. As a

result, it is feasible to inspect how small atomistic changes (~0.1 nm) on a given system might

influence its overall behavior on a much larger scale (~100 nm).

In our group we have specialized in using this ultimate multi-scale modeling tool to bring

atomistic insight into the Scanning-Probe-Microscopy experiments performed by world

leading SPM experimental groups on a wide variety of topics. In this study we present some

results concerning the passive vertical adsorption of antibodies over an inorganic surface. In

this work we have used very-large-scale molecular dynamics together with atomic-force-

microscope experiments to show that antibodies adsorb to graphene without any protein

unfolding, finding that antibodies adsorb over graphene preferentially on bioactive

orientations. In addition we will present some results that explain the behavior of DNA

single-base sensitive biosensors based on cantilevers.




6

PLENARY 4

Using Pulsed Laser Deposition to Build Active Optical Metamaterials

R. Serna, J. Toudert, M. Jiménez de Castro, I. Camps, A. Mariscal and A. Cuadrado

Laser Processing Group, Insituto de Optica, CSIC, Madrid (Spain)

Optical metamaterials understood as materials including sub-wavelength structures will be

essential for the building of the next generation of photonic devices. These metamaterials

will have functionalities such as emission, switching/processing and detection of light and

will operate in a wide wavelength range, from the UV to the NIR. These effective meta-

functionalities can be achieved by suitably assembling active nanoscale structures with

different functionalities in a single host element.

I will present the methodology that we have developed in our group in order to build

metamaterials based in the concept of embedding nano-scale objects into thin film oxides

using pulsed laser deposition. By suitably choosing the nature/composition, morphology and

size of these nanoscale objects, thin films with specific functional responses have been

obtained. In this presentation I will show and discuss some examples of our recent work that

include efficient nano-hybrid emitters in the near-infrared, wide band emitters in the visible,

and non-conventional plasmonic components operating in the visible.




7

PLENARY 5

Self-assembly and surface-mediated crystallization of

inorganic-organic materials Brad Chmelka

Department of Chemical Engineering

University of California, Santa Barbara

Santa Barbara, California 93106 U.S.A.

[email protected]

Surfactant-directed syntheses of mesostructured inorganic materials involve coupled kinetic

processes of self-assembly, cross-linking, and/or crystallization that are strongly influenced

by surface effects. Self-assembly of such materials generally depends on interactions among

amphiphilic surfactant species, soluble inorganic precursors, solvent, and functional guest

species, which in the case of sol-gel-derived oxides, results in liquid-crystal-like mesophases.

Typically, such materials are synthesized under non-equilibrium conditions, in which cross-

linking of soluble inorganic oxide species occurs simultaneously with surfactant self-

assembly to form mesostructured inorganic-surfactant composites with amorphous inorganic

frameworks. For certain compositions and conditions, crystallization of the inorganic

frameworks can also occur, leading to changes in mesostructural order that yield layered

silicate or mesostructured zeolite products. The associated kinetic processes are mediated by

interactions among the inorganic, solvent, surfactant, or other species, which affect the rates

and selectivities by which products form, along with their resulting compositions, structures,

and morphologies. The molecular-level interactions that underlie these complex interrelated

processes and associated material properties have been challenging to measure, understand,

and control. Nuclear magnetic resonance (NMR) spectroscopy circumvents many of the

challenges by being sensitive to local atomic environments and provides information that is

complementary to scattering, electron microscopy, and macroscopic property measurements.

By correlating results from these different methods, new multiscale insights are obtained on

the compositions, structures, and properties of surfactant-directed inorganic-organic

materials and how they change with time. Recent results will be presented on the molecular

interactions and influences of surface species on the self-assembly and crystallization of

mesostructured silicate, borosilicate, or aluminosilicate materials, and their implications in

heterogeneous catalysis.

mailto:[email protected]




8

PLENARY 6

Tribological Visions of Charles Chaplin and Richard Feynman

Prof. Dr. Esteban Broitman

Thin Film Physics Division, IFM, Linköping University, SE581 83 Linköping, Sweden

By the end of the second industrial revolution, Charles Chapin shows in his masterpiece silent movie

“Modern Times” a futuristic factory where tribological operators clean and lubricate big machines [1]. His

vision probably reflects the popular belief that, in the future, macromachines will relief mankind from heavy

work. That is also accounted in most of tribological studies at that time, reporting macroscale wear and

lubrication.

The seed idea for developing micro- and nano-machines was probably introduced in 1959 by the physicist

Richard Feynman in his lecture “There’s Plenty of Room at the Bottom” [2]. He considered that direct

manipulation of matter at atomic scale will be used in a near future to build tiny machines that could arrange

the atoms and perform chemical synthesis by mechanical manipulation. Nowadays, micromachines in the size

range of 100 nm to 100 µm, known also as MEMS (micro-electro-mechanical systems), are used in

accelerometers for automotive systems, inkjet printer heads, game controllers, hard disks, and rotation sensors

for smartphones.

Most of commercial micromachines are designed as transducers for applications with no contact or sliding:

they are either sensors or actuators. Despite of niche industrial applications with designs of more complex

MEMS devices containing moving mechanical assemblies (MEMS-MMA) like micromotors, gears and

levers, the commercial production of these kind of machines is inexistent. The main problem in

micromachines is tribological: the presence of stiction, high friction and wear between the small components

[3]. Friction becomes critical on the microscale and is one of the fundamental limitations in the design of

reliable micromotors, microgenerators, and microengines. Lubrication for decreasing friction and wear in

these devices is difficult, because capillary forces created by confining liquids to small geometries is in the

same order of magnitude than actuation forces generated by micromachines. Therefore, only solid or vapor-

phase lubrication can be used. However, there are some applications like stepper motors taking advantage of

friction: with step sizes on the order of 10 to 100 nm, and actuation forces in the milli-Newton scale, they

could be used for positioning optical, data storage, and medical applications.

In this talk, after a short historical introduction, I will focus on the main tribological challenges of sliding

micromachines. Friction and lubrication of Chaplin’s macromachines and Feynman’s micromachines will be

compared. Finally, I will show some present developments leading to Feynman’s vision of machines at the

nanometer scale.

[1] C. Chaplin, Director and actor, Modern Times. [Film], 1936.

[2] R. P. Feynman, There’s Plenty of Room at the Bottom, Engineering and Science, February issue (1960)

22-36.

[3] E. Broitman, The nature of the frictional force at the macro-, micro-, and nano-scales, Friction 2 (2014)

40-46.




9

PLENARY 7

Laser produced periodic patterns: fundamentals and applications

R. J. Peláez, C. N. Afonso

Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, E-28006 Madrid, Spain

e-mail address: [email protected]

This contribution will show that laser interference is a versatile attractive tool for creating a

variety of periodic micro/nano patterns that diffract light and exhibit colors. It represents a

cost and time effective alternative to the very costly and multi-step lithographic

methodologies. These patterns are interesting in several sectors such as photonics, consumer

industry, security or solar cells as well as have a high potential as platforms for bio assays or

sensing. The features and spatial limits of the patterns depend on the material properties and

configuration and the pattern period and motives can be tailored to the application envisaged

through a number of parameters. The underlying mechanisms as well as their time scales, the

parameters playing an essential role on the process and the variety of patterns accessible will

be illustrated through patterns produced on two very different materials: porous silicon layers

and ultrathin metal layers having plasmonic response. Finally, the potential of some these

platforms for bio assays will be illustrated through the successful alignment of cells in culture

on selected patterns with high potential for tissue regeneration.




10

PLENARY 8

Droplet epitaxy for III-V semiconductor nanostructures

Luisa González

IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC)

The droplet epitaxy growth technique was firstly used at the beginning of the 1990s by Koguchi et

al.[1]. It was proposed as a development of the molecular beam epitaxy (MBE) for the fabrication of

III–V semiconductor nanostructures on II–VI semiconductor substrates with nearly equal lattice

constant. It basically consists of the deposition of atoms of group-III element in absence of any supply

of group-V element, creating liquid metal droplets on the substrate. These metal droplets are, right

afterwards, exposed to an atmosphere of group-V element, which induces their crystallization into

III–V nanostructures. This technology permits to obtain quantum nanostructures on heteroepitaxial

systems with or without lattice mismatch, representing an actual advantage over well-established

Stranski-Krastanow processes where the strain is the driving force for nanostructures formation

Depending on the substrate temperature, this growth method yields different types of nanostructures.

For example, on GaAs (001) substrates, quantum dots (QD) [2] and quantum rings (QR) complexes

[3] are formed at relatively low temperatures of 200–300 C, whereas nanoholes surrounded by

mounds [4, 5] are obtained at high substrate temperatures (500C). In particular these nanoholes can

be used as a template to obtain both strained and strain-free QD by filling them with a semiconductor

with a smaller band-gap than that of the host matrix [5]. Within this approach, the size and shape of

the resulting nanostructures can be modified independently of the areal density. The simultaneous

control of QD density and emission wavelength is crucial for applications as single photon emitter

devices.

In this paper, the potential of droplet epitaxy for nanostructures formation will be described, with

emphasis on the mechanisms of nanoholes formation, mandatory in order to take advantage of all the

potential of droplet epitaxy as a nano-patterning technique [6].

References [1] N. Koguchi et al., J. Cryst. Growth 111, 688–692 (1991)

[2] J.S. Kim, et al., Appl. Phys. Lett. 85, 5893–5895 (2004)

[3] T. Mano, et al., Nano Lett. 5, 425–428 (2005)

[4] Z.M. Wang, et al., Appl. Phys. Lett. 90, 113120 (2007)

[5] P. Alonso-González, et al., Appl. Phys. Lett. 91, 163104, (2007)

[6] Fuster, D. et al., Nan. Res. Lett 9, 309 (2014)




11

PLENARY 9

Reconfigurable and Tunable photonic molecules for optical signal

processing

Prof. Newton C. Frateschi

IFGW – UNICAMP, Brasil

Optical interconnection and photonic integration are essential for the realization of the

ubiquitous computing that arises from the Internet of Things (IOT) scenario. There is an

urgent demand for bandwidth increase, system size reduction, all with power consumption

reduction. We have recently demonstrated silicon/silica based photonic molecules, i.e.,

planar coupled optical resonators, for optical signal processing. In these structures, the

photonic properties or optical signal processing functions are optimized by utilizing the

coupled supermodes instead of a sequence of individual modes of independent resonators in

the same fashion as one combines atoms to engineer molecular properties. These devices

overcome the existing intrinsic interdependence between photonic lifetime, resonance

spacing and footprint for single micro resonators, introducing a new degree of freedom to

perform spectral engineering. Optical carrier recycling, potential for modulation beyond

resonance bandwidth limit, and low-power wavelength multicasting using multiple-split

resonances in micrometer-scale devices have been demonstrated. [1–3]. In this talk we will

first focus on the several aspects of utilizing photonic molecules for spectral engineering with

a review of the above results. Finally, we will focus on new active structures where

reconfigurable and continuously tunable mode-splitting in a multi-GHz range is achieved

with very low resonance shift. [4] A new class of devices is shown to provide great flexibility

in designing devices for optical signal processing using very compact structures based on a

CMOS compatible technology.

1. L. A. M. Barea, F. Vallini, G. F. M. de Rezende, and N. C. Frateschi, "Spectral Engineering

With CMOS Compatible SOI Photonic Molecules," IEEE Photonics J. 5, 2202717–2202717

(2013).

2. L. A. M. Barea, F. Vallini, P. F. Jarschel, and N. C. Frateschi, "Silicon technology

compatible photonic molecules for compact optical signal processing," Appl. Phys. Lett. 103,

201102 (2013).

3. M. C. M. M. Souza, L. A. M. Barea, F. Vallini, G. F. M. Rezende, G. S. Wiederhecker, and

N. C. Frateschi, "Embedded coupled microrings with high-finesse and close-spaced

resonances for optical signal processing," Opt. Express 22, 10430–10438 (2014).

4. Mario C. M. M. Souza, Guilherme F. M. Rezende, Luis A. M. Barea, Antonio A. G. von

Zuben, Gustavo S. Wiederhecker, and Newton C. Frateschi, Spectral engineering with

coupled microcavities: active control of resonant mode-splitting,” Optics Letters, 40 (17), pp.

3332-3335 (2015)




12

PLENARY 10

Functional Defects in Nanodiamond Particles: Challenges and

Opportunities

Gary E. McGuire and Olga A. Shenderova

Adámas Nanotechnologies Inc., Raleigh, North Carolina

Nanodiamond (ND) particles have recently emerged as a key platform for many sectors of

nanoscience and nanotechnology due to their outstanding mechanical performance,

biocompatibility and distinctive optical properties, a combination of assets not often met in

the nanoworld. Two recent major breakthroughs, production of individual 4-5nm particles

(single-digit NDs) and particles containing color centers exhibiting stable luminescence and

unique spin properties have brought ND particles to the forefront of materials research.1 It is

important to be aware, though, that the method of synthesis of NDs influence their structure

(morphology, size, state of doping elements) and, therefore, their properties and niche

applications. This aspect will be discussed in more details. Commercially available

nanometer size particles are produced by detonation of carbon-containing explosives (called

detonation nanodiamonds) or by grinding of microdiamond powders produced by phase

transformation of carbon precursors under high pressure and high temperature (HPHT).

While the former are a source of single-digit NDs, the latter are a basis for production of NDs

containing color centers (particularly nitrogen-vacancy centers) with uniquely coupled

fluorescent and spin properties. Development of multimodal imaging probes based on 5-

10nm ND with a high density of NV centers and doping of ND with new functional elements

are future directions for this field. A goal of this talk is to provide a general background on

ND particles, more in-depth review of functional defects in NDs and outline current and

perspective applications of ND in areas which have broad societal impact.

1V.Mochalin, O.Shenderova, D.Ho and Y.Gogotsi, “The properties and applications of

nanodiamonds”, (2012) Nature Nanotechnology, 7 (1) 11-23.




13

PLENARY 11

Optical properties II-VI semiconductors materials

O. Zelaya-Angel

Department of Physics, Centro de Investigación y de Estudios Avanzados del IPN. P.O.

Box 14-740, México 07560 D.F.

Nanostructured samples of II-VI semiconductor compounds can be prepared in powders, thin

films, rods, membranes, etc. format by means of a large variety of techniques such as:

sputtering, chemical bath, and pulsed laser deposition. Binary, ternary and quaternary phases

information have found many useful applications in modern industry. The more common

experimental techniques employed to study the optical properties of the semiconductor

materials are: Optical absorption, Raman spectroscopy, photoreflectance, and fluorescence.

This information is supported by X-ray diffraction, microscope images, and electron

dispersión spectroscopy. In our work, stress, phase transitions, optical band gap variations,

vibrational modes shifts, electromagnetic emissions in the visible región, etc. have been

studied in CdS, CdSe, CdTe, CdO, ZnS, ZnSe, ZnTe and ZnO binary sistems; and CdTeO,

CdSbTe, CdInTe, etc, ternary compounds. As instance, in a zinc blende – wurtzite (cubic to

hexagonal) transformation of CdS, the band gap reaches a minimum value in the critical point

and the green photoluminescence band splits in two bands (yellow and green) due to a lot of

Cd-interstitials generated in the transition.




14

COURSE A

Surface Preparation for Thin Film Deposition

Gary E. McGuire

Adámas Nanotechnologies Inc., Raleigh, North Carolina

Course Objectives:

Understand the nature of surfaces (practical and technologically significant).

Learn about surface preparation, sample handling, and contamination control.

Develop insight into surface characterization and analysis.

Learn about surface preparation and film nucleation during thin-film deposition.

Course Description

Substrate preparation is an integral part of any film deposition process. This includes

removing unwanted impurities and residues as well as conditioning the surface to promote

adhesion through activation, or interfacial layers. The selection of the cleaning and surface

preparation techniques is dependent on the nature of the surface and the deposition

technique.

This course reviews surface cleaning and preparation techniques, condensation and

nucleation of the deposited atoms, film-substrate interface formation, and the initial stages

of film growth. Both wet and dry cleaning procedures will be discussed with an aim

towards remove of ionic, metallic and organic residues as well as particles. Emphasis will

be placed on atomistic and reactive deposition utilizing evaporation, sputtering, chemical

vapor and molecular beam deposition. Film properties, such as intrinsic stress, which may

affect adhesion will be reviewed. Techniques used to characterize the elemental

composition, chemical state, and phase of material will be illustrated for both in situ and ex

situ analysis.

Who Should Attend?

Scientists, engineers, technicians, supervisors, and others who are involved in the

deposition of materials in vacuum or controlled ambients, and who want to learn about the

effects of surface preparation and condition on the nucleation and growth of films and the

subsequent interfacial adhesion and film properties. Knowledge of elemental physics and

chemistry is helpful in assimilating the course material, but it is not essential.




15

Course B

Nanostructured hard coatings and special topics on their Characterization

Yip-Wah Chung

Northwesthern University, USA

The short course on nanostructured coatings will have two parts. The first covers enhanced

hardness of nanostructured coatings, strategies to improve thermal stability, and applications

in dry machining. The second part covers special topics on the characterization of such

coatings, including grain size, residual stress, hardness, and fracture toughness




16

COURSE C

Spin-Orbit Interaction in Bulk Materials, Surfaces and Two-Dimensional

Crystals

Sergio E. Ulloa

Department of Physics and Astronomy and Nanoscale and Quantum Phenomena Institute,

Ohio University, Athens, Ohio 45701, USA.

This course discusses the microscopic origin of spin-orbit interaction in materials and some

of its consequences on their band structure, as well as its role in determining observables that

reveal the dynamics of electrons and excitons in different systems.




17

COURSE D

Raman spectroscopy Workshop for chemical and material identification

in materials research.

Richard W. Bormett

Renishaw Incorporated

This workshop will provide a review of the theory and the application of Raman spectroscopy

techniques useful to the scientific community. Raman spectroscopy has been proven to be

capable of providing material and chemical analyses of samples that may vary in size from

the very large to the sub-micron, and that maybe in sealed containers (under glass or plastic).

New advances in technology now allow Raman microscopy to be extended from the optical

microscopes to AFM and SEM microscopes. Raman imaging supports a number of “fast”

chemical and topographical contrast methods that can greatly simplify area composition

distribution analysis. There will be emphasis on Raman microscopy, with imaging

techniques that reveal layers and material distributions, for example in cells, and advanced

materials including composites. A live demonstration of Raman microscopy with 785 nm

and 532 nm excitation and the imaging processing and acquisition capabilities of dispersive

multi-wavelength Raman system will be available so attendees are encouraged to bring

microscope compatible samples.




18

COURSE E

Epitaxia de haces moleculares (MBE): Nanoestructuras cuánticas de

semiconductores III-V

Luisa González

IMM-Instituto de Microelectrónica de Madrid (CNM_CSIC)

http://www.imm-cnm.csic.es/mbe

La epitaxia de haces moleculares (MBE) es un proceso de crecimiento que se utiliza para una gran

variedad de materiales por su capacidad para producir láminas delgadas de muy alta pureza y

excelente calidad cristalina. Partiendo de un sustrato monocristalino, es posible encontrar las

condiciones adecuadas para que el crecimiento sea epitaxial, de modo que la estructura cristalina de

la lámina esté determinada por la del sustrato. Fue utilizada por primera vez para el crecimiento de

semiconductores compuestos y aún sigue siendo éste su uso más común, si bien se ha extendido a

diversos sistemas materiales que incluyen óxidos y metales.

El proceso MBE tiene lugar en condiciones de ultra-alto vacío y permite producir capas epitaxiales

con control muy preciso en composición y dopado, así como intercaras abruptas a escala atómica.

Mediante MBE se han podido realizar estructuras consideradas como modelos en física de estado

sólido (pozos cuánticos QW, hilos cuánticos QWR y puntos cuánticos QD), y éstas se han utilizado

para la fabricación de dispositivos de nuevo diseño, como transistores de alta movilidad,

dispositivos emisores de fotones individuales, o en el desarrollo de elementos optoelectrónicos ya

existentes de características avanzadas.

En este curso se introducirán los conceptos básicos que definen el crecimiento epitaxial por MBE y

se describirán los equipos y sus componentes. Como ejemplo de sistemas materiales crecidos por

MBE, se describirá el crecimiento y propiedades de heteroestructuras de semiconductores III-V,

centrándonos en nanoestructuras que presentan confinamiento cuántico (QW, QWR, QD). Se

introducirán las principales técnicas de caracterización in situ y en tiempo real del proceso de

crecimiento de nanoestructuras semiconductoras. Finalmente se describirán otros procesos de

crecimiento epitaxial basados en MBE y algunas aplicaciones.

Bibliografía

Molecular beam epitaxy, Y. Cho and J. R. Arthur, Prog. Solid State Chem. 10, 157-191

Molecular beam epitaxy: applications to key materials. Robin F. C. Farrow, ed. Noyes Publications,

USA, 1995

Molecular beam epitaxy, John R. Arthur, Surf. Sci. 500 (2000) 189-217

http://www.imm-cnm.csic.es/mbe




19

COURSE F

Practical Peak-Fitting of XPS Data

Alberto Herrera Gómez1, Servando Aguirre Tostado2

1 Cinvestav-Queretaro, Libramiento Norponiente 2000, Real de Juriquilla, Queretaro

76230, México 2 Centro de Investigación en Materiales Avanzados, S.C.(CIMAV), Av. Alianza Norte #202,

Parque de Investigación e Innovación Tecnológica (PIIT), Nueva Carretera Aeropuerto

Km. 10, Apodaca, Nuevo León, México. C. P. 66600.

This short course will be aimed to providing practical tools for peak-fitting X-ray

Photoelectron Spectroscopy (XPS) data. The issues that will be discussed are the

following:

• Simple methods for analyzing simple data.

• Tools for analyzing complex data.

• Background modeling.

• Practical line shapes for asymmetric peaks.

• The physical origin of the various elements in a spectrum.

• The physical meaning of each of the parameters employed during peak-fitting.

The participants will be invited to share their experiences with the technique and to bring

their own data for open discussion.




20

TECHNICAL TALK I

Diffraction and Beyond: The Modern Multipurpose Diffractometer

Jorge Pablo González

PANalytical Mexico

Most of the laboratory diffractometers are dominated by Cu sources … but why?

The modern X-ray diffractometers can analyze powder, thin films & surfaces with many

more X- ray scattering techniques than just diffraction.

Reflectivity it’s the first “non-diffraction” type of analysis that we can do with X-ray

Diffractometers. This technique has been available on lab based diffractometers for quite a

while. New two dimensional detectors can be used for GISAXS to study surface

microstructure & topography to study defects on thin films. This new techniques can

complement the traditional x ray analysis like x ray reflectivity & GIXRD. During this

presentation we will cover how one instrument can offer these tools to get more information

about thin films, nano-particles and solid materials and some In situ experiments that can be

performed easily with one technology available on the Lab




21

TECHNICAL TALK II

Avance en la Tecnología de Bombas Turbomoleculares por PFEIFFER

VACUUM.

. Edward Ho

Pfeiffer Vacuum

Temas:

Turbobombas con tecnología Mag Lev y “ball bearing”

Estaciones de bombeo HiCube de Pfeiffer con tecnología ACP

Estaciones de bombeo con funcionamiento intermitente de "bajo nivel de

ruido / operación verde".

Sistemas Especializados de Pfeiffer en bombas turbomoleculares

Bombas turbo HiPace ultra-alto vacío

Aplicaciones móviles para bombas turbo HiPace 10 - HiPace 30




22

AB-INITIO CALCULATIONS AND

SUPERCOMPUTING (ACS)

Chairmans:

Dr. Naboru Takeuchi (CNYN-UNAM),

Dr. Gregorio Hernández Cocoletzi (IF-BUAP)

Oral Sessions

[ ACS-59 ] Density Functional Theory Study of the Organic

Functionalization of Hydrogenated Graphene, Silicene and

Germanene

Pamela Rubio Pereda ([email protected]) 1 , Noboru Takeuchi Tan2

1 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) 3918,

Postal Code 22860, Ensenada, Baja California, Mexico. 2 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México,

Postal Code 22800, Ensenada, Baja California, Mexico.

Silicene and germanene, the silicon and germanium analogous of graphene, are two newly

synthesized two-dimensional nanomaterials and as graphene, they all present unique features

and promising potential applications that already have attracted worldwide attention. The

organic functionalization of these nanomaterials could provide the necessary tools for the

molecular level manipulations that the microelectronic industry will demand within the next

decades. In particular, the organic functionalization with molecules containing unsaturated

C−C bonds by means of a radical initiated reaction constitutes a favorable route for the

attachment of organic layers.

In this work, computer simulations were applied to model the chemical behavior of graphene,

silicene and germanene hydrogen terminated surfaces towards the radical initiated reaction

with acetylene, ethylene and styrene molecules. The understanding of these chemical surface

reactions was studied with the use of the density functional theory. For each case, atomic

structures for different stages of the reactions were optimized with the inclusion of van der

Waals dispersion forces and potential energy profiles were derived to evaluate the chemical

reaction performance.




23

Results indicate that silicene and germanene are good candidates for organic

functionalization due to low activation energy barriers. Nevertheless, the hydrogenated

graphene system was found to be more difficult to be organic functionalized than the other

surfaces of silicene and germanene. This difference is attributed to the rather small carbon

lattice structure and repulsion issues due to the similarity in the electrostatic potential

between graphene and organic molecules.

We acknowledge partial financial support from Conacyt project 164485-F.

[ ACS-289 ] Ultrafast charge dynamics and metallic domain

growth in monoclinic VO2

Jose Mario Galicia Hernandez ([email protected]) 2 , Volodymyr

Turkowski 1 , Talat S. Rahman 1 , Gregorio Hernandez Cocoletzi 2

1 Department of Physics, UCF, 4000 Central Florida Blvd, Orlando, FL 32816, USA 2 IFUAP, BUAP, Av. San Claudio y Blvd. 18 Sur, Col. San Manuel, Puebla, Puebla, Mexico

We apply a combined time-dependent density functional theory (TDDFT) and dynamical

mean-field theory (DMFT) approach to study the ultrafast response of insulating

(monoclinic) vanadium dioxide (VO2) system to a perturbation by an ultrafast laser pulse.

Namely, the ground state properties and the excitation energies of the system were studied

by using a DFT approach followed by DMFT calculations to take into acount strong electron-

electron interactions. We considered two types of perturbations: a homogeneous and a local-

in-space ultrafast laser pulses. The system response

was calculated with TDDFT with the nonadiabatic (frequency-dependent) exchange-

correlation (XC) kernel obtained from the DMFT solution for the effective Hubbard model.

We analyze the details of the dynamics of the breakdown of the metal-insulator transition

and the relaxation of the system to equilibrium. In particular, in the case of local-in-space

excitation we establish the time-dependence of the metallic domain size at different values of

the local Coulomb repulsion and the XC kernel parameters. We demonstrate that the memory

effects (time-resolved electron-electron interactions),

taken into account by the nonadiabatic XC kernel, play an important role in the response of

the system.




24

INVITED TALK

[ ACS-345 ] Atomic-scale sliding friction of graphene in water

Pedro Serena 1 , J.G. Vilhena 1 , Carlos Pimentel 1 , Patricia Pedraz 1 , Feng

Luo 1 , Carlos Pina 1 , Enrique Gnecco 1 , Ruben Perez 1

1 Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, Madrid, Spain

It is a long accepted fact that friction is a very complex process whose understanding and

description is beyond the reach of classical phenomenological laws. Nevertheless only

recently, advances in the measurement technologies and instrumentations allowed us to take

a closer look at these processes. In particular, Atomic-Force-Microscopy has helped to reveal

many new insights associated with friction at atomic-scale. Nevertheless, the interpretation

of these experiments, i.e. convolution between the imaging signal and the tip/surface

interactions, is far from straightforward. In vacuum, this gap was filled with molecular-

dynamics simulations. These allowed us to have a better understanding of the atomic scale

processes/interactions occurring at the tip-surface interface, thus unlocking a new unexplored

possibilities. (channel of information) of AFM.

Here we report molecular-dynamics simulations in which we simulate an FFM measurement

of the atomic-scale friction properties of graphene/graphite embedded in water. In our

simulations we use atomistic classical potentials and Jarsynski steered molecular-dynamics

methods to measure the free energy variations as we scan the surface. Taking the derivative

of these free energies differences we are able to reconstruct the FFM friction force curves

including entropic contributions arising from the interaction of the water molecules with the

AFM tip. Our findings, not only are in excellent agreement with the experimental results, but

also show how in water we can recover FFM atomic contrast, only previously obtained in

ultra-high-vacuum conditions. Furthermore, our atomistically detailed simulations allow us

to shed light on the origin of this outstanding resolution, in particular in the role played by

the water molecules in this kind of measurements.




25

[ ACS-374 ] Fe adsorption and incorporation into the

Mn3N2(001) surfaces

Jonathan Guerrero-Sánchez ([email protected]) 1,3 , Andrada-Oana

Mandru 3 , Noboru Takeuchi 3 , Noboru Takeuchi 2 , Gregorio H. Cocoletzi 1

, Arthur R. Smith 3

1 Benemérita Universidad Autónoma de Puebla, Instituto de Física “Ing Luis Rivera

Terrazas”. 2 Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autónoma de México.

3 Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute.

Ohio University.

We have investigated the Fe adsorption and incorporation in the Mn3N2(001) surfaces using

first-principles spin-polarized total energy calculations. Adopting a surface formation energy

criterion it is demonstrated that the Fe incorporation is energetically favorable for all

surfaces. The bilayer formation is obtained when Fe replaces Mn atoms in the N-vacancy

layers. The magnetic coupling shows an antiferromagnetic alignment in the z direction as

that one presented by the bare surfaces. Furthermore, the in-plane magnetic coupling between

Fe-Fe and Fe-Mn shows a ferromagnetic behavior in all cases. These results clearly indicate

that Fe behaves in a similar fashion as Mn in the sub-surface. The stable structures density

of states show a deviation from the antiferromagnetic behavior, with the Fe-d and Mn-d

orbitals making the most important contribution at the vicinity of the Fermi level.

[ ACS-505 ] Theoretical study of luminescence witnessed in

nanostruc-tured Silicon Rich Oxide films ascribed to defects in

the inter-face with silicon agglomerates

Nestor Espinosa ([email protected]) 2 , David Hernández 1 , Javier

Martinez 1 , Francisco Flores 1 , Alberto Luna 1

1 CIDS 2 CIDS ICUAP

The electrical and optical properties of Si-based materials, like Silicon Rich oxide (SRO),

are of special importance for their application in optical fibers technologies, and

optoelectronic devices are determined, together with other mechanisms, by local structural




26

defects. Thus, considerable efforts have been made in the past decades to understand the

structural, optical and electronic properties of point defects in SRO. Recently, quantum-

chemical calculations have proved increasingly useful for the study of the structure and

properties associated with point defects in amorphous isolators and semiconductors. In

particular, a cluster approach based in ab initio calculus has provided several new

discernments into the microstructure of local defects in SRO and it is claimed that it may a

bridge the gap between the properties of isolated molecules and the condensed phase[1].

The interest about the optical properties of SRO has been increased starting from it was

confirmed that SRO films exposed to high-temperature annealing exhibit efficient

photoluminescence (PL) In general, luminescent properties can provide meaningful

information regarding the crystalline structure of a material and, in the case of Silicon Rich

Oxides thin films, their luminescence properties are on the whole important since these films

can be used to fabricate luminescent devices.

Recently we published the Global Reactions Model (GRM)[2] to describe a set of chemical

reactions that could hypothetically occur during the process of obtaining silicon rich oxide

(SRO) films, notwithstanding of the technique used to grow such films. Particularly,

chemical reactions that occur during the process of growing of SRO films by Low Pressure

Chemical Vapor Deposition (LPCVD) and Hot Filament Chemical Vapor Deposition

(HFCVD) techniques were emphasized in these model[i]. We suggest and evaluate either

some types of molecules or resulting nanostructures and we have predicted theoretically, by

applying the density functional theory (DFT), the contribution that they may have to the

phenomenon of luminescence. We calculated the luminescent spectra of the as grown and

the annealed structures.

References

[1] T. Uchino. Ab initio cluster calculations on point defects in amorphous SiO2. Current

Opinion in Solid State and Materials Science 5 (2001) 517–523

[2] A new Model for Prediction of luminescent comportment of nanostructured Silicon Rich

Oxide. N.D. Espinosa-Torres, J.A. Luna-López, A.D. Hernández de la Luz, J.F.J. Flores-

Gracia, J. Martínez-Juárez and G. Flores-Carrasco. International Journal of Innovative

Science, Engineering and Technology. Volume 4, Issue 2, March 2015. ISSN: 2319-5967.




27

Poster Sesion

[ ACS-26 ] Bulk Bands projected , surface states and resonant

states of chrome in the crystallographic directions (001) and

(110)

Hernán Javier Herrera Suárez 3 , Alberto Rubio-Ponce 1 , Daniel Olguín 2

1 Departamento de Ciencias Básicas, Universidad Autónoma Metropolitana–Azcapotzalco,

Av. San Pablo 180, México, D.F. 02200, México. 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, Apartado Postal 14740, México, D.F. 07300, México. 3 Universidad de Ibagué, Facultad de Ciencias Naturales y Matemáticas, Colombia,

Carrera 22 Calle 67 Barrio Ambalá.

In this work we present a detailed study of the electronic band structure of the (001)

and (110) of Chrome. For our study we use the tight-binding approach and the surface Green

function matching method. First, we study the electronic properties of the transition metals

in volume, we use tigth-binding Hamiltonians in the Slater Koster formalism (SK). We using

an orthogonal atomic basis of nine spd atomic orbitals, for each atom in the unitary cell. The

parameters of the model, in the two centers approach, were taken from of the handbook of

electronic band structure published by Papaconstantopoulos. These parameters reproduce the

electronic band structure and the total density of states properly of each one of the different

studied transition metals. For the study of the surfaces we use the surface Green function

matching method. We verify that the local density of states, projected in the volume, agrees

with the results obtained for the infinite case reported by Papaconstantopoulos. Next, we

make a detailed study of the different characteristic surface states and resonant states for the

crystallographic surfaces (001) and (110). We find that our results compare acceptably well

with the previous published values, and we make the prediction of new different states not yet

reported in the literature. We report a catalog of these surface states.




28

[ ACS-55 ] Structural and electronic properties of Eu doped

ZnO Nanorods

José Luis Cervantes López ([email protected]) 2 , Ricardo Rangel

Segura 2 , Donald Homero Galván Martínez 1 , Juan Francisco del Rosario

Estrada Cruz 1

1 Centro de Nanociencias y Nanotecnología - UNAM, Km 107 Carretera Tijuana-

Ensenada, Pedregal Playitas, CP 22860, Ensenada, Baja California 2 Universidad Michoacana de San Nicolas de Hidalgo, Posgrado en Ingeniería Química,

Francisco J. Mujica s/n col. Felicitas del Río, CP 58030, Morelia Michoacán, México.

The synthesis of one-dimensional single crystalline ZnO nanostructures has been a growing interest,

due to their promising applications in nanoscale devices. This comes from their interesting physical

properties; such as wide and direct band gap, large exciton binding energy, high electron mobility

and high thermal conductivity [1]. Doping ZnO with rare earth and 4d transition elements it’s an

interesting technique to tune up the optical properties of ZnO. In the present work, the structural and

electronic properties of ZnO and Eu-doped ZnO nanorods with hexagonal shape were investigated

through of Density Functional Theory (DFT) calculated trough Local Density Approximation (LDA)

and Perdew-Zunger for exchange and correlation. The relative stability after inclusion of elements

into the ZnO host lattice was studied. The ground state properties, equilibrium bond lengths, and band

structures of ZnO and doped-ZnO system has also been investigated.

References

[1] Giancarlo Cicero, Madani Samah Slimane Haffada, "Structural and electronic properties of ZnO

nanowires: a theoretical study ," SciVerce Sciencedirect , no. 10, pp. 128-137, 2011.

[2] Yuebin Zhang, Rong-Kun Zheng, Simon Peter Ringer and Sean Li Mohammad Hussein Naseef

Assadi, "Structural and electronic properties of Eu- and Pd-doped ZnO ," Nanoscale Research Letters

, 2011.

[3] Anderson Janotti and Chris G Van de Walle, "Fundamentals of zinc oxide as a semiconductor,"

REPORTS ON PROGRESS IN PHYSICS, pp. 1-29, 2009.

[4] Bin Wen, Roderick V.N. Melnik, Tingju Li Zhiwen Yang, "Geometry Dependent Current-Voltage

Characteristics of ZnO Nanostructures: A Combined Nonequilibrium Green’s Function and Density

Functional Theory Study ," APPLIED PHYSICS LETTERS , pp. 1921011-1921013, 2009.

[5] A. L. Rosa, Th. Frauenheim, R. Q. Zhang and S. T. Lee Hu Xu, "Density-functional theory

calculations of bare and passivated triangular-shaped ZnO nanowires ," APPLIED PHYSICS

LETTERS , pp. 0319141-0319143, 2007.

[6] Q. Jiang and G. W. Yang S. Li, "Uniaxial strain modulated band gap of ZnO nanostructures ,"

APPLIED PHYSICS LETTERS , no. 96, pp. 2131011-2131013, 2010.

[7] Philip B. Allen, James T. Muckerman, James W. Davenport, and Jin-Cheng Zheng Xiao Shen,

"Wire versus Tube: Stability of Small One-Dimensional ZnO Nanostructures ," NANO LETTERS ,

vol. 7, no. 8, pp. 2267-2271 , 2007.




29

[ ACS-64 ] Quantum chemical studies of biophysical systems

with interest in medical applications

Dolores Garcia Toral ([email protected]) 1 , María del Rosario

Melchor Martínez 1

1 FIQ-BUAP Prol 14 Sur s/n Cd Universitaria, 72570 Heróica Puebla de Zaragoza, Pue.

The main objective is to present a quantum chemical study for caffeine, dopamine, ephedrine,

phenytoin, primidone and norepinephrine, all of these in its molecular form, which are

involved in medical treatment for cardiovascular and nervous system primarily. It has a

ranking of the most relevant of each of the molecules, such as electronic molecular structure

as well as its use primarily physicochemical and medical and general information. The theory

used for this study is based on the density functional essentially report the values of hardness

and chemical softness, which were studied and were calculated for each above-mentioned

structure. Displaying the results graphically and numerically in terms of the highest occupied

molecular orbital and lowest unoccupied molecular orbital.

[ ACS-92 ] First principles equations and chemical synthesis of

yttrium oxide

S. Valdez ([email protected]) 3 , I.E. Diaz Ramos 3 , S. Robles C. 4 , Ociel

R.P. 3 , A. Bautista H. 2 , M.I. Pech-Canul 1

1 Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional

Cinvestav-Saltillo. Coahuila 25900, Mexico 2 Fac. De Ingeniería. Benémerita Universidad Autonoma de Puebla. Apdo. Postal. J-39.

Puebla Puebla. 72570 Mexico. 3 Instituto de Ciencias Físicas-UNAM Campus Morelos. Av. Universidad s/n. Col.

Chamilpa. CP 62210. Cuernavaca, Morelos México 4 Universidad Autonoma del Estado de Morelos, CIICAP. Av. Universidad 1001. Col.

Chamilpa. CP 62210. Cuernavaca, Morelos México.

Whereas yttrium oxide is a compound having good chemical stability, high dielectric

strength, and high resistance to electrochemical degradation, we have been studying their

structural properties. At the theoretical level, we have applied a method for calculating the

structural properties of yttrium oxide from first principles equations within the framework of




30

Density Functional Theory (DFT). The exchange-correlation functional used was the local

density approximation (LDA). From these calculations we have determined the lattice

parameter, the bulk modulus and Young's modulus. At the experimental level, we have

synthesized the particles of yttrium oxide by a chemical substitution reaction between yttrium

nitrate and ammonium hydroxide. The resulting precipitates of yttrium oxide were oxidized

at 800 ° C. The crystal structure of the yttrium oxide powder was obtained with X-ray

diffraction by the Rietveld method. The results were compared with those reported for the

yttrium oxide obtained by hot isostatic pressing.

[ ACS-130 ] Structural and electronic properties of doped

clusters: A DFT study.

David Mora-Herrera ([email protected]) 1 , Martín Salazar-

Villanueva 1

1 Facultad de Ingeniería, BUAP, Puebla Puebla

In this work clusters of transition metals were considered with different geometries. All of

them were optimized with a smart algorithm based on DFT (Density Functional Theory). The

total energy, HOMO-LUMO gap and vibrational frequencies have been obtained. The

HOMO-LUMO gap with Koopmans’s approximation was the criterion taken into account to

establish the chemical stabilities of these systems. The electronic properties like vertical

ionization potential, vertical electronic affinity and chemical hardness are discussed.




31

[ ACS-142 ] Vacancy Effects on the Electronic Properties of

Silicene Nanoribbons under Strain

J. Hernández-Tecorralco 2 , M. R. Chávez-Castillo

([email protected]) 1,2, L. Meza-Montes2 , M. A. Rodríguez-Meza 1

1 Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, 11801, México,

D.F, México 2 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Postal J-48,

72570, Puebla, Pue., México.

In the recent emergence of two-dimensional materials, scientists have shown great interest in

other graphene-like systems. Despite the fact that graphene possesses extraordinary physical,

chemical, and mechanical properties which make it attractive for wide range of applications

in the nanotechnology field, it has the disadvantage that it may be not easily integrated with

the actual silicon-based technology. Silicene, the silicon counterpart of graphene, has gained

much attention due to its similarity to graphene. As a result, silicene could be used for

applications not only in nano-electronics but also in nano-electromechanical systems. Since

nanoribbons (NRs) exhibit different edge geometries, i. e., armchair and zig-zag chiralities,

the properties could be determined by the width and chirality of the NR. Moreover, properties

could be manipulated by doping, strain and defects.

In this work, we study the response of electronic and mechanical properties of Silicene-NRs

to the presence of a monovacancy defect. The Quantum Espresso package is employed in

this study to perform calculations in the framework of Density Functional Theory method.

The structural parameters, band structure, and electronic density of states are analyzed in

both chirality directions in pristine and vacancy-defect Silicene-NRs without strain. As the

electronic properties could be affected by strain, we performed calculations for the case when

tensile strain is applied. We found our results are in good agreement with previous results

for the pristine case.




32

[ ACS-160 ] First principle calculations of the disorder double

perovskite Sr2FeMoO6

Abdul Mauricio Reyes Usuga ([email protected]) 1,2 , , Yesenia

Arredondo León 3 , Oracio Navarro Chavéz 4

1 Unidad Morelia, Instituto de Investigaciones en Materiales, Universidad Nacional

Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San

José de la Huerta, 58190, Morelia, Michoacán, México. 2 Facultad de Ciencias Físico Matemáticas, Universidad Michoacana de San Nicolás de

Hidalgo, Av. Francisco J. Mojica S/N, Ciudad Universitaria, Morelia, Michoacán, México 3 Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional


José de la Huerta, 58190, Morelia, Michoacán, México. 4 Unidad Morelia, Instituto de Investigaciones en Materiales, Universidad Nacional


José de la Huerta, 58190, Morelia, Michoacán, México

First principle calculations were done in the double perovskite Sr2FeMoO6 compound

regarding the effects of cationic disorder and the electronic correlation in the ground-state

properties like the spin polarization and the magnetic saturation. In the calculation we use

the formalism given by the Generalized Gradient Approximation (GGA) including the U

Hubbard term. The results show that the disorder breakdowns the half-metallic behavior of

the above compound and the magnetic saturation decreases.




33

[ ACS-186 ] Ideal strength and elastic stability of InX (X=N, P,

As, Sb, Bi) compounds with zinc-blende structure

Juan Carlos Moreno Hernandez 2 , Jose Humberto Camacho Garcia

([email protected]) 2 , Maria de Lourdes Ruiz

Peralta 2 , Alejandro Bautista Hernandez 1 , Martin Salazar

Villanueva 1

1 FI-BUAP 2 FIQ-BUAP

In this work, we present a study of hydrostatic compression ideal strength of InX

(X=N,P,As,Sb,Bi) compounds with a zinc-blende (ZB) structure by first principles

calculations. Lattice parameters, bulk, shear, and Young´s modulus, are obtained in the

ground state. The elastic constants are obtained as a function of applied stress. The results

shows a good agreement respect to theoretical and experimental data. The ideal strength of

each compound was calculated using the Born-Wang elastic stability criteria.

[ ACS-222 ] First principles calculations of phenol adsorption

on pristine and hydrogenated Al-doped boron nitride sheet.

Yuliana Elizabeth Avila Alvarado ([email protected]) 3 , María Teresa

Romero de la Cruz 2 , Gregorio Hernández Cocoletzi 1

1 Benemérita Universidad Autónoma de Puebla, Instituto de Física "Luis RiveraTerrazas" 2 Universidad Autónoma de Coahuila, Facultad de Ciencias Físico Matemáticas

3 Universidad Autónoma de Coahuila, Facultad de Ciencias Químicas

First principles total energy calculations have been performed to study the structural and electronic

properties of phenol adsorption on pristine (BN) and hydrogenated Al-doped (Al-BN) boron

nitride sheet. Calculations have been made within the periodic density functional theory as

implemented in the PWscf code of the QUANTUM ESPRESSO package. The exchange-

correlation energies were treated with the generalized gradient approximation (GGA).

Electron-ion interactions were modeled with pseudopotentials. The electron states were

expanded in plane waves with an energy cutoff of 30 Ry. A supercell with 4x4 periodicity

was used. In addition, the non-local correlation energies were accounted using the van der

Waals density functional (vdW-DF) method. The most stable configuration for BN-phenol




34

systems was the parallel orientation onto stacked site, in this case the molecule was placed

upon N atom. For hydrogenated Al-BN phenol system, Al doping induces a strong interaction

between the phenol molecule and doped layer yielding chemical adsorption. Also the

electronic band structure was calculated for the most stable configurations. The BN-phenol

system keeps the insulating property with an indirect band gap approximately 4.1 eV. These

results are in good agreement with previous reported results. Hydrogenated Al-BN system

shows a metallic behavior.

[ ACS-290 ] Solving the Schrödinger Equation for the Yukawa

potential in ideal circular and square Quantum Wires.

Reyna Méndez Camacho ([email protected]) 2 , Ramón Castañeda

Priego 1 , Esteban Cruz Hernández 2

1 2División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del

Bosque 103, León, Gto., México. 2 Coordinación para la Innovación y la Aplicación de la Ciencia y Tecnología, CIACYT-

UASLP, Sierra Leona 550, S. L. P., S. L. P., México.

The study of one-dimensional (1D) quantum confined systems is of great importance due to both, the

new phenomena triggered by the strong 1D electronic interactions and its inherent potential

applications as nanowire components. Semiconductor nanowires (NWRs) are 1D emerging materials

that, through controlled growth and organization, can be exploited in the fabrication of novel

nanoscale photonic and electronic devices [1]. Even when electronic confinement has been

theoretically studied by a variety of theoretical models and simulation methods, there is not a

methodic study of the problem of two electrons interacting under a Yukawa potential, which is a

potential frequently used to simplify the many-electron problem of diverse systems. In this work, we

present the solution of the Schrodinger equation for the case of two electrons confined into NWRs of

square and circular infinite potential barriers.

Correlation degree between pair of electrons are presented as a function of the electronic shielding

strength. In order to confirm the validity of our numerical method, the limit cases for the screening

parameter k were evaluated to recover the limit of two electrons interacting under: a) a Coulomb

potential (k tending to 0), b) into the bulk material (large cross section) and, c) free electron (k tending

to infinity). We report the dependence of both the energy levels and the charge density with the

geometry of the NWRs and the value of the k parameter.

[1] Yat Li, Fang Qian, Jie Xiang, and Charles M. Lieber, Materials today, Vol. 9, Issue 10, (2006),

18–27.




35

[ ACS-297 ] Numerical Solution of the Schrödinger Equation

for the Yukawa potential in an Al(x)Ga(1-x)As/GaAs

Quantum Wire

Reyna Méndez Camacho ([email protected]) 1 , Ramón Castañeda

Priego 2 , Esteban Cruz Hernández 1

1 Coordinación para la Innovación y la Aplicación de la Ciencia y Tecnología, CIACYT-

UASLP, Sierra Leona 550, S. L. P., S. L. P., México. 2 División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del

Bosque 103, León, Gto., México.

Semiconductor quantum wires (QWRs) offer many opportunities for the assembly of

nanoscale electronic and optoelectronic devices. In these one-dimensional (1D) systems,

discrete energy states and strong confinement of charge carriers, photons and phonons lead

to unique 1D properties that have potential in a wide range of applications, such as lasers,

solar cells or biological sensors. In order to deeply understand some of these unique

properties, many mathematical models and simulations have been proposed. In this work we

present a methodic study of the problem of two electrons into an AlxGa1-xAs/GaAs QWRs

interacting under a Yukawa potential (YP). The YP has been frequently used to simplify the

many-electron problem of diverse systems. In this work, we present the solution of the

Schrödinger equation for the case of two electrons confined into AlxGa1-xAs/GaAs QWRs of

square and circular potential barriers.

The proposed model is dependent on the temperature, the Aluminium concentration (by using

the Varshni model), the index of the substrate (implicit in the effective mass), the dopant

level (associate at the screening parameter κ in the YP), and the cross section geometry of

the QWR (circular or square). For the real case (experimental values), we take 1013-1017 e-

/cm3, the (631) Miller index, a temperature of T=300K, an Aluminium concentration

of x=0.23, an electron-electron distance the order of the laticce parameter of the GaAs

(a=0.56535nm) and a wall-electron potential in the conduction band of V=0.65 [Egap(AlxGa1-

xAs)-Egap(GaAs)]. We then report the dependence of both the energy levels and the charge

density with the geometry of the QWRs and the value of the k parameter.




36

[ ACS-330 ] Surface modes of a negative face velocity

Fibonacci multilayer structure

Xóchitl Ines Saldaña Saldaña ([email protected]) 1 , Gregorio

Hernández Cocoletzi 2

1 Instituto de Física, Benemérita Universidad Autónoma de México 2 Instituto de Física, Benemérita Universidad Autónoma de Puebla

Using the transfer matrix theory [1], we present a numerical study of the surface modes

propagating at the interface of a homogeneous medium in contact with a multilayer structure

constructed following the Fibonacci recurrence formula Sj+2 = Sj+1&Sj (j = 0,1,2,3,…) where

& means concatenation. Here S0 = B represent a dielectric homogeneous slab with refractive

index nb and thickness db and S1 = A represent a strongly anisotropic non-magnetic slab [2]

constructed with nanospheroids aligned and homogeneously distributed in an isotropic

dielectric host with thickness da. A criterion for the existence of the surface modes is

developed and compared with the periodic case.

[1] P.Yeh, Optical Waves in Layered Media, Wiley, New York (1988).

[2] P. H. Hernández, G. Martínez, G. H. Cocoletzi, H. A. Coyotecatl, and J. Díaz, J. Appl.

Phys. 101, p. 093103-1 (2007).

Acknowledgement:

Work partially supported by CA250 Materiales Avanzados, VD-BUAP, México




37

[ ACS-346 ] Molecular Dynamics Simulation of BSA

Adsorption on a Stepped Graphite Surface.

Yuliana Elizabeth Avila Alvarado1,2 , Pamela Rubio Pereda 1,3 , Perceval

Velosillo 1 , Pedro A. Serena ([email protected]) 1 , Rubén Pérez 4

, Guilherme Vilhena1,4 , María Teresa Romero de la Cruz 2

1 Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, Spain 2 Universidad Autónoma de Coahuila, México

3 Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE),

Ensenada, Baja California, México 4 Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid,

Spain

To obtain well-ordered immobilized biomaterial arrays for the integration of bio-sensing

units in the semiconductor device technology or to better comprehend protein adsorption

onto implant materials based on carbon substrates, certain properties of the substrate surfaces

such as surface topography, play a major role in biomedical engineering and biotechnology

applications. One main topographical feature is the presence of surface atomic-level

structures that in contact with protein solutions of different concentrations show, in

accordance with SPM studies, that protein adsorption occurs preferentially along step edges,

where a higher chemical reactivity is expected. To address this problem, we have studied the

adsorption of the model globular protein BSA onto a graphene surface with topographic

features via molecular-dynamics atomistic simulations. The level of detail in our simulations

such as the inclusion of explicit solvent, physiological ion concentrations and long time

dynamics, allow us to address with better detail this mechanism. Results show that initial

protein diffusion toward substrate occurs much faster with the presence of surface atomic-

level structures, followed by an initial biased protein diffusion when adsorbed onto atomic

structures with sizes over 10 Å height due to the lack of van der Waals short range

interactions. Moreover the low loss in a–helical contents of BSA adsorbed supports the

capability of biofunctionalization of graphene.




38

[ ACS-365 ] Ab initio calculation of the effect of Oxygen on the

electronic properties of hydrogenated [110] oriented SiC

Nanowires

Alejandro Trejo Baños ([email protected]) 1 , José Luis Cuevas

Figueroa 2 , Álvaro Miranda Durán 3 , Miguel Cruz Irisson 1

1 Instituto Politécnico Nacional, ESIME Culhuacán, Av. Santa Ana 1000 col. San Francisco

Culhuacán, C.P. 04430 D. F. México 2 Universidad Autónoma Metropolitana- Xochimilco Calzada del Hueso 1100 col. Villa

quietud Del. Coyoacán C. P. 04960 México D. F. 3 Universidad Nacional Autónoma de México, Instituto de Física, Apartado Postal 20-364,

México D. F., México

Silicon carbide nanowires (SiCNWs) have been of interest to many researchers due to their

attractive properties, such as: high mechanical strength, high thermal conductivity, chemical

inertness and wide gap energy for applications in electronics, optics, advanced engineering

and nanoelectromechanical switches. There are some theoretical and experimental

investigations of SiCNWs, mainly focused on the [001], [111] and [112] growth directions,

and none about [110] oriented nanowires due to their lower stability compared to the other

three directions. However, the [110] oriented SiCNWs could be interesting for applications

in microelectronics due to its peculiar symmetry which is similar to a nanotube. This work

studies the effects of hydrogen and Oxygen in the electronic band gap of Silicon Carbide

Nanowires (SiCNW) grown in [110] direction by means of Density Functional Theory. We

compare electronic properties of H passivated SiCNWs in comparison to a mixed passivation

of O and H by changing some of the surface dihydrides with Si–O–Si or C–O–C bonds. The

results show that regardless the diameter and passivation most of the nanowires have a direct

band gap which suggest an increased optical activity. The surface C–O–C bonds reduce the

electronic band gap energy compared to the H-terminated phase while the nanowires with

Si–O–Si bonds have a higher band gap. The calculation of formation energies show that the

oxygen increases the chemical stabilization. These results indicate the possibility of band gap

engineering on SiC nanostructures through the surface passivation.




39

[ ACS-394 ] Van der Waals interactions in the organic

molecules encapsulation within boron nitride zigzag nanotubes

Raúl Alfonso Vazquez Nava ([email protected]) 1 , Ramsés Valente Salazar

Aparicio 1 , Gregorio Hernández Cocoletzi 2

1 Departamento de Fotonica, Centro de Investigaciones en Óptica 2 Instituto de Física, Benemérita Universidad Autónoma de Puebla

First principles total energy calculations are performed to investigate the structural and

electronic properties of the organic molecule encapsulation within boron nitride nanotubes

(BNNTs) with zigzag chirality. Eight organic molecules are explored: glycine, serine,

cysteine, cytosine, thymine, uracil, adenine and guanine. Three different approaches are used;

Hartree-Fock, density functional theory (DFT) and DFT-D3 which includes dispersion

corrections. The finite length single wall BNNTs, with (12,0) chirality, are composed of six

BN bilayers which are terminated by nitrogen at one end and by boron at the other end.

Hydrogen atoms are used to saturate dangling bonds. Ground states structures are reported

which are used to determine the total density of states of the molecule encapsulation. Binding

energies calculations show chemical interactions between the molecule and the NT. The

energy gap of the bare NT is modified by the molecule encapsulation; in some cases this gap

increases while it decreases in others. The change in the bandgap size is produced by the

molecules and NT orbital hybridization. These results suggest the BNNT use in the drug

transportation within the human body to cure diseases.




40

[ ACS-395 ] Second-harmonic generation studies of

nanotubes: First principles calculations

Raúl Alfonso Vázquez Nava ([email protected]) 1 , Ramses Valente Salazar

Aparicio 1 , Gregorio Hernández Cocoletzi 2

1 Departamento de Fotonica, Centro de Investigaciones en Óptica 2 Instituto de Física, Benemérita Universidad Autónoma de Puebla

We present ab initio calculations to investigate the second harmonic generation (SHG)

response of single wall zigzag nanotubes. Studies have been performed using the density

functional

theory (DFT) within the local-density approximation (LDA) together with the GW Green

function method to determine the band gap. A length gauge approach has been used to

calculate the

nonlinear optical response with the scissors correction to obtain the nonlinear susceptibility

of the zigzag nanotubes. Our results show that, contrary to reports in the literature, the (5,0)

and

(9,0) nanotubes display non vanishing SHG response.




41

[ ACS-418 ] DFT STUDY OF THE ELECTRONIC AND

STRUCTURAL PROPERTIES OF A PbS QUANTUM DOT-

SUPPORTED TiO2 NANOPARTICLE

Tania Gabriela Diaz Rodriguez ([email protected]) 1 , Jesus Muñiz Soria2

, Mauricio Pacio Castillo 1 , Hector Juarez Santiesteban 1

1 CIDS,BUAP, Ciudad Universitaria, San Manuel, Código Postal 72570, Puebla,Mexico 2 IER, UNAM, Xochicalco, Azteca, 62588 Temixco, Mor.

The geometric and electronic structure were determined for a junction of two semiconductor

nanoparticles: (TiO2)38[1] and PbS, with different geometries reports experimentally for

PbS: Cubic and centering on plane [1 1 1][2,3]. Also different PbS

stoichiometries were verified into TiO2-PbS system to find the ideal gap sizes. These

predictions will be implemented in the laboratory. The structure of the ground electronic state

of both nanoparticles were determined using Density Functional Theory (DFT) calculations

using FHI-AIMS[4] package. The densities of states (DOS) of these particles were calculated

in vacuum. Next the atomic and electronic structure of their junction was determined. The

calculations were performed at the level of DFT, using a plane-wave basis set, and the

generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof for the exchange-

correlation energy [5]. The core electrons were described with Projector Augmented Wave

(PWA) method, also were included relativistic scalars effects (ZORA)[6] and Van Der Waals

interactions using Tkatchenko-Scheffler methodology[7]. Since the photocatalytic activity of

a system is determined by its atomic and electronic structures the results derived here provide

fundamental data to develop and design photocatalytic systems for hydrogen production.

[1]Xiabo Chen, Semiconductor-based Photocatalytic Hydrogen Generation, Chem. Rev., 110

(2010).

[2] K. Donghun, Impact of Stoichiometry on the Electronic Structure of PbS Quantum

Dots,Phys. Rev. Lett., (2013).

[3] B. Kiran, (PbS)32:A baby crystal,J. Chem. Phys., (2012).

[4]. V. Blum, R. Gehrke, F. Hanke, P. Havu, V. Havu, X. Ren, K. Reuter, M. Scheffler.

Comp. Phys. Comm. 180 (2009), 2175.

[5] J.P Perdew,Generalized Gradient Approximation Made Simple, Phys. Rev. Lett., (1996).

[6]R. Ahuja, A. Blomqvist, P. Larsson, P. Pyykkö, and P. Zaleski-Ejgierd, Relativity and the

Lead-Acid Battery. Physical Review Letters 106, 018301 (2011).

[7]. A. Tkatchenko and M. Scheffler, PRL 102, 073005 (2009)




42

[ ACS-452 ] DFT study of the interaction of amine group with

aflatoxin B1

Luis Angel Juárez-Morales 1 , Heriberto Hernández-Cocoletzi

([email protected]) 1 , Eva Águila-Almanza 1 , Ernesto Chigo-Anota 1

1 Facultad de Ingeniería Química, BUAP, Av. San Claudio y 18 sur S/N CU, San Manuel

Edif. 106A, C. P. 72570 Puebla México

Contamination by aflatoxin B1 (AfB1) affects food, especially cereal grains. Depending on the

exposition time the AfB1 may be carcinogenic, hepatotoxic, and teratogenic1. It is produced by the

Aspergillus flavus and Aspergillus parasiticus fungi2. To prevent damages associated with AfB1 it is

necessary its isolation and/or its mitigation. There are different approaches to face the problem,

ranging from the physical separation of contaminated grains to chemical treatments; the

nixtamilizacion process is also considered a good option. The former has led to the fungus and/or

aflatoxin more resistant, requiring larger amounts or concentrations, giving rise to some damage to

the grain and eventually to humans and animals, including the environment. Recently it has been

shown that synthetic chitosan is able to inhibit the growth of both the AfB1 and the fungus that

produces it3. There is an increasing interest on the use of antifungal compounds obtained from natural

resources such as chitosan obtained from shrimp exoskeletons4, which is non-toxic, biodegradable,

biocompatible3 and it has low cost. It has been shown experimentally that chitosan adsorb AfB15;

however, it is not known if the adsorption is chemical or physical, important feature for separation

process. The amine group of chitosan plays the fundamental role in the interaction, then, a theoretical

study is required. In this work we show that amine group is physically adsorbed on AfB1 by using a

DFT study. The GAUSSIAN 09 code is employed.

1. Kannewischer I., Tenorio A. M. G., White G. N., y Dixon J. B. (2006). Clay Science,

Japan. vol. 12(2):99-204.

2. Guzman de Peña D. (2005). Rev. Lat. de Microb. vol. 47(3-4):160-164.

3. Cota A. O., Cortez R. M. O., Rosas B. E. C., Burgos H. A., López F. Y. L. y

Plascencia J. M. (2011). Polymer International. vol. 40: 937-944.

4. Hernández C. H., Águila A. E., Flores A. O., Viveros N. E.L. y Ramos C. E. (2009).

Sup. y Vac., vol. 22(3):57-60.

5. Balseca-López D. M., Hernández-Cocoletzi H., Tenorio-Arvide M. G., Aguila-

6. Almanza E., Esparza-Ibarra E., Revista Latinoamericana el Ambiente y las Ciencias,

6, (2015) 2784.

Acknowledgements: This work has been partially supported by VIEP-BUAP.




43

[ ACS-482 ] Indigo and dehidroindigo encapsulation in

palygorskite clay: An ab initio study with VDW-DF

interactions

Francisco Sánchez Ochoa ([email protected]) 3 , Gregorio

Hernández Cocoletzi 3 , Gabriel Iván Canto Santana 1 , Noboru Takeuchi

Tan 2

1 Centro de Investigación en Corrosión, Universidad Autónoma de Campeche, 24039

Campeche, México. 2 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México,

Km 107 Carretera Tijuana-Ensenada, CP. 22800 Ensenada, B.C, México. 3 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J48,

72570 Puebla, México.

In this work we perform ab-initio calculations to investigate the structural, binding and

electronic properties of palygorskite clay housing organic molecules such as indigo (IND)

and dehidroindigo (DHI). This system is the well-known Maya blue pigment. Studies are

performed within the periodic density functional theory. The electron-ion interactions are

treated with pseudopotentials, and the exchange-correlation energies are modeled according

to the VDW-DF functional. Studies start by determining the structural parameters of the pure

paligorskite (Pbmn) clay and the isolated molecules, IND and DHI. The nano-hybrid

IND/DHI@clay was modeled with 1x1x3 and 1x1x5 supercells where the organic dyes are

housed. Binding energy profiles are calculated for the diffusion of dye(s) through the

nanotúnel with and without zeolitic water molecules in the same tunnel. Additionally we

have determined the total density of states and the partial density of states for the most stable

structures to show that, the electronic properties around the Fermi level are governed by the

guest dyes. Finally, charge density differences show the redistribution of charge when the

dispersion effect is included in the VDW-DF exchange-correlation functional.




44

ATOMIC LAYER DEPOSITION(ALD)

Chairman:

Pierre Giovanni Mani González (UACJ)

Oral Session

[ ALD-58 ] Chirality in Amino Acid Overlayers on Cu

Surfaces

Leonardo Morales de la Garza ([email protected]) 1 , David A.

King 2 , Stephen M. Driver 2 , Miriam L. Clegg 2

1 Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología.

Apdo. Postal 14, Ensenada, Baja California, MÉXICO, 22800. 2 University of Cambridge, Department of Chemistry. Cambridge CB2 1EW, UK

Chirality at surfaces has become a strong focus within the surface science community. A particular

motivation is the prospect of using heterogeneous catalysis over chiral solid surfaces for asymmetric

synthesis, a prospect which has clear relevance to the pharmaceutical industry. Small amino acids

adsorbed on Cu surfaces have emerged as important model systems for studying the interaction of

chiral molecules with metal surfaces. We review the current state of knowledge of these systems, and

present the results of new experimental studies of alanine overlayers on Cu311 and 531 surfaces.

Our work on Cu311 helps us to understand the interplay between different manifestations of

chirality, especially ‘‘footprint chirality’’, in the overlayers. Cu531 is an intrinsically chiral surface

orientation; our data reveal strongly enantiospecific alanine-induced restructuring of this surface. This

points the way towards a promising route for obtaining strongly enantiospecific interactions with

chiral adsorbates.

ACKNOWLEDGMENT

The authors thank Dr. M. Blanco Rey, Prof. R. Raval and Drs. A. Mark, M. Forster and S. J. Jenkins

for valuable discussions. The EPSRC is acknowledged for financial support, L. Morales de la Garza

acknowledged finantial support from DGAPA-UNAM.

REFERENCE

[1] Topics in Catalysis (2011) 54:1429–1444




45

[ ALD-271 ] Electrical characterization of ALD Al2O3/ZnO

nanolaminates

Jesús Martínez ([email protected]) 1 , Javier Lopez 1 , Roberto

Machorro 1 , David Domínguez 1 , Eduardo Murillo 1 , Mario Curiel 2 ,

Nikola Radnev 2 , Mario Farías 1 , Hugo Tiznado 1

1 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México,

Apdo. Postal 14, C.P. 22800, Ensenada, México 2 Instituto de Ingeniería, Universidad Autónoma de Baja California, Blvd. Benito Juárez y

calle de la Normal s/n Col. Insurgentes Este. CP. 21280 Mexicali, Baja California. México

Abstract: Atomic layer deposition (ALD) is an ideal technique in order to growth composite

thin films. The thickness and stoichiometry of thin films prepared using ALD is dependent

on the underlying surface chemistry during ALD film growth. Composite thin films

fabricated by co-depositing two or more different materials via ALD technics can be

combined to form alternating layers in order to obtain multilayered laminates. Alternatively,

the composite materials may be homogeneously mixed to form alloys. A wide range of

physical properties can be achieved by varying the relative proportions of the components;

this strategy has been used previously to control numerous thin film properties including

refractive index, dielectric constant, lattice parameter, hardness, charge storage capacity, and

surface roughness. We used zinc oxide for this research work how to main material, due to it

is a known material and used in electronic applications, which it is characterized by its low

cost and wide availability. Zinc oxide has new applications as semiconductor, luminescent,

and photoconductive materials respectively, while, the aluminum oxide (Al2O3) is one of the

most widely used materials in the family of ceramics. It is known as a material with good

chemical stability, extremely high hardness and relatively high thermal conductivity. Al2O3

thin films are used as dielectric gate in electronic devices, because it has a high - K dielectric

value, being a material with interesting physical properties useful in areas such as micro and

optoelectronics.

Deposited films were electrically characterized through measurements of the capacitance as

a voltage function. Also we made studies of current vs. voltage in order to obtain the electrical

properties of the material. Finally, the dielectric constant, equivalent oxide thickness (EOT)

and charge density were calculated by these measurements.

Keywords: High-K oxide, ALD, electrical properties, thin films.

Acknowledgments




46

This work was supported by research project PAPIIT - IN105114, PAPIIT - IN107715 and

CONACyT - 238402. The authors would like to thank Alex Tiznado, Enrique Medina,

Margot Sainz, Juan Peralta and Pedro Casillas,

References

1. Kattelus, H.; Ylilammi, M.; Saarilahti, J.; Antson, J.; Lindfors, S. Thin Solid Films

1993, 225, 296

2. Stromme, M.; Niklasson, G. A.; Ritala, M.; Leskela, M.; Kukli, K. J. Appl. Phys.

2001, 90, 4532.

3. Fujiwara, H.; Nabeta, T.; Shimizu, I. Jpn. J. Appl. Phys. 1994, 33, 2474.

4. Chu, X.; Wong, M. S.; Sproul, W. D.; Barnett, S. A. J. Mater. Res. 1999, 14, 2500.

5. Kukli, K.; Ritala, M.; Leskela, M. J. Appl. Phys. 1999, 86, 5656.

6. Elam, J. W.; Sechrist, Z. A.; George, S. M. Thin Solid Films 2002, 414, 43.

7. Khalid Omar, M. D. Johan Ooi & M. M. Hassin, Modern Applied Science, 2009,

Vol.3, No. 2.

8. Puurunen R. L. J. Appl. Phys, 2005, Vol. 97, pp. 121301.

9. Jiang Ran, Meng Lingguo, Zhang Xijian, Hyung-Suk Jung, and Cheol Seong Hwang.

Journal of Semiconductors, 2012, Vol. 33 (9), 093004.

[ ALD-274 ] Electrical characterization of ALD Al2O3/Y2O3

nanolaminates



Nikola Radnev 2 , Mario Farías 1 , Hugo Tiznado ([email protected]) 1




Abstract: Dielectric materials based on metallic oxides as ZrO2, Al2O3, Y2O3, TiO2, are very

interesting properties and exhibiting high - K dielectric constants which improve the

electrical properties in the different devices for microelectronic and optoelectronic

applications in nanotechnology specially for microchip-embedded that provides energy

storage in high-capacitance capacitors. Aluminum oxide (Al2O3) is one of the most widely

used materials in the family of ceramics. It is known as a material with good chemical

stability, extremely high hardness and relatively high thermal conductivity. Al2O3 thin films




47

are used as dielectric gate in electronic devices, because it has a high - K dielectric value, being a

material with interesting physical properties useful in areas such as micro and optoelectronics.

Yttrium oxide (Y2O3) is a material with several interesting diverse applications due to its thermal

stability with a high melting point (2439°C), optical transparency from 300 nm to ~11 µm range, high

refractive index, and useful electrical properties. In optical applications, its high refractive index can

be used in the manufacturing of optical waveguides and multilayer dielectric coatings that might

enhance the optical surfaces for optoelectronic applications in order to modify the transmittance and

reflectance properties of the materials to which are applied. Atomic layer deposition (ALD) is an ideal

technique for fabricate composite thin films. The thickness and stoichiometry of composite thin films

prepared using ALD is dependent on the underlying surface chemistry during ALD film growth.

Composite thin films may be fabricated by co-depositing two or more materials that may be combined

in alternating, discrete layers to form multilayered laminates. These composite materials can be

homogeneously mixed to form alloys. A wide range of physical properties may be achieved by

varying the relative proportions of the components. This strategy has been used previously to control

numerous thin film properties including refractive index, dielectric constant, lattice constant,

hardness, charge storage capacity, and surface roughness.

Deposited films were electrically characterized through measurements of the capacitance as a voltage

function. Also we made studies of current vs. voltage in order to obtain the electrical properties of the

material. Finally, the dielectric constant, equivalent oxide thickness (EOT) and charge density were

calculated by these measurements.

Keywords: High-K oxide, ALD, electrical properties, thin films

Acknowledgments


CONACyT 238402. The authors would like to thank Alex Tiznado, Enrique Medina, Margot Sainz,

Juan Peralta and Pedro Casillas.

References

1. Jiang Ran, Meng Lingguo, Zhang Xijian, Hyung-Suk Jung, and Cheol Seong Hwang. Journal

of Semiconductors, 2012, Vol. 33 (9), 093004.

2. Prodyut Majumder, Gregory Jursich, Adam Kueltzo and Christos Takoudis, Journal of The

Electrochemical Society, 155 (8) G152-G158 (2008)

3. Kattelus, H.; Ylilammi, M.; Saarilahti, J.; Antson, J.; Lindfors, S. Thin Solid Films 1993,

225, 296

4. Stromme, M.; Niklasson, G. A.; Ritala, M.; Leskela, M.; Kukli, K. J. Appl. Phys. 2001, 90,

4532.

5. Fujiwara, H.; Nabeta, T.; Shimizu, I. Jpn. J. Appl. Phys. 1994, 33, 2474.

6. Chu, X.; Wong, M. S.; Sproul, W. D.; Barnett, S. A. J. Mater. Res. 1999, 14, 2500.

7. Kukli, K.; Ritala, M.; Leskela, M. J. Appl. Phys. 1999, 86, 5656.

8. Elam, J. W.; Sechrist, Z. A.; George, S. M. Thin Solid Films 2002, 414, 43.




48

[ ALD-351 ] Soft nitridation of ALD-hafnium oxide by remote

plasma

Zeuz Montiel González ([email protected]) 1 , Yuri Lizbeth

Chipatecua Godoy 1 , Jorge Alejandro Torres Ochoa 1 , Oscar Ceballos

Sánchez 1 , Gustavo Gómez Sosa 1 , Andrés de Luna Bugallo 1 , Alberto

Herrera Gómez 1

1 Cinvestav-Queretaro, Libramiento Norponiente 2000, Real de Juriquilla, Queretaro

76230, México

Currently, there is an intensive search for high-k materials that can replace SiO2 as gate

dielectric in metal-oxide-semiconductor (MOS) devices. In this context, several deposition

methods and/or chemical treatments have been employed to improve their chemical and

electrical properties. The incorporation of nitrogen into the dielectric does not only improves

the value of the dielectric constant but it also reduces the leakage current, prevents interfacial

reactions and increases the crystallization temperature. Several approaches to the nitridation

of the dielectric have been studied, for instance the thermal exposure to N sources, direct

contact with N plasma, and treatment with a N remote plasma source (RPS). In this work, a

study of the remote plasma nitridation of HfO2 grown with atomic layer deposition (ALD) is

presented. The nitridation was carried out under a pressure of 0.1 Torr and with a flow rate

of 100 sccm of ultra-high purity N2 for 10 minutes. The degree of nitridation and the nitrogen

incorporation mechanism were evaluated as a function of the RPS power (0.5, 1.0 and 1.5

kW) and the dielectric temperature (300, 400 and 500 °C). The analysis of the structure of

the HfOxNy films was done with angle resolved X-ray photoelectron spectroscopy. The

results showed a strong dependence on the plasma power and dielectric temperature, and the

presence of different nitrogen species distributed along the HfO2 layer.




49

[ ALD-373 ] Application of ALD for the Research &

Development of Advanced Logic, Memory and Sensing

Technologies.

Joel Molina ([email protected]) 1 , Berni Manolo Perez Ramos 1 , Hector

Uribe 1 , Rene Valderrama 1 , Omar Lopez 1 , Oscar Pestaña 1

1 Instituto Nacional de Astrofisica, Óptica y Electrónica (INAOE), Grupo

de Microelectrónica.

We review the application of Atomic-Layer Deposition for development of advanced logic,

memory and sensing technologies being developed at INAOE. The focus is on the deposition,

processing and performance characterization of advanced MOSFET, FinFET,

ReRAM, ISFET and ISCAP devices along with the fundamental problems associated to the

deposition of ALD-dielectrics for these technologies.

[ ALD-400 ] Growth and Characterization of TiO2 Films

Grown by Atomic Layer Deposition for photocatalytic

applications

María Magdalena Montsserrat Contreras Turrubiartes

([email protected]) 1 , Aura Pedrosa Rodríguez 2 , Juan Carlos

Salcedo Reyes 2 , Pierre Giovanni Mani González 3 , Edgar López Luna 1

1 Coordinación para la Innovación y Aplicación de la Ciencia y la Tecnología, Universidad

Autónoma de San Luis Potosí, Av. Sierra Leona #550, Col. Lomas 2a. Sección 2 Pontificia Universidad Javeriana de Bogotá, Carrera 7 # 40-62, Bogotá, Colombia

3 Universidad Autónoma de Ciudad Juárez, Av. Plutarco Elías Calles 1210, Col. Fovissste

Chamizal, 32310 Ciudad Juárez, CHIH

Due to the current global needs of efficient processes for purification of waste waters has

recently been a significant increase in research, in particular, heterogeneous photocatalysis

by titanium dioxide , due mainly to its ability to induce chemical reactions of oxidation and

reduction of the oxygen molecules adsorbed on the semiconductor/medium interface ,

producing the proven effect biocide and sterilizing of TiO2 . Although studies have been

conducted with other semiconductor photocatalysis mainly CdS and CdSe , it has been




50

observed that with TiO2 the higher is obtained. In addition, the TiO2 material is inexpensive,

non-toxic

and chemically inert biological. The study of the photocatalytic properties of TiO2 were

performed with films formed from a suspension of titanium powder (in anatase phase) TiO2

thin films can be grow by other methods as: Sol- gel, sputtering, spray-pyrolysis and Atomic

Layer Deposition. In this paper we present the results for establish the parameters for the

growth of thin films of titanium dioxide (TiO2) in anatase phase by Atomic Layer Deposition

(ALD), their optical characterization through photoluminescence (PL) , and surface

characteristics by atomic force microscopy (AFM) . It also proposes a study of the efficiency

of photocatalytic TiO2 films grown by ALD, depending on the film thickness, by means of

the time-dependent decrease in the degradation of color units using as one model contaminant

solution of methylene-blue, for potential applications in sewage purification. Also shows the

results for inactivation test for E.Coli bacteries.

[ ALD-412 ] Determination of the surface saturation,

aperture-times and number of cycles of HfO2 and TiO2 on Si

(100) by ALD

Pierre Giovanni Mani González ([email protected]) 2 , María

Magdalena Montsserat Contreras Turrubiartes 1 , Edgar Lopez Luna 1 ,

Hugo Leos Méndez 2 , Heber Hernández Arriaga 1 , Jesús Alfredo

Hernández Márquez 2 , José Rurik Farías Mancilla 2 , José Trinidad

Elizalde Galindo 2 , Miguel Ángel Vidal Borbolla 1

1 Coordinación para la Innovación y Aplicación de la Ciencia y la tecnología (CIACyT),

Universidad Autónoma de San Luis Potosí 2 Instituto de Ingeniería y Tecnología, Departamento de Física y Matemáticas, Universidad

Autónoma de Ciudad Juárez

A systematic analysis was performed to determine the characteristic times of surface

coverage of oxidant-agent on silicon substrates (100) by the method of atomic layer

deposition (ALD) in order to ensure the saturation of the surface substrate for growth. The

aperture-times of the precursors have been studied due to stoichiometric impact of the layers

and also at the interface. The numbers of cycles were critical for the interface formation at

the early stage growth. This work emphasizes in the study and analysis of the growth surface

evolution (amount of free bonds) with respect to the aperture-times of hafnium or titanium

precursor remains open (saturation time) and with amount of cycles as function of layers and




51

interfaces (stoichiometry). Previous works complement with results obtained in study the

growth of hafnium oxide and titanium oxide by atomic layer deposition (ALD) demonstrating

the close relationship between the thickness and composition of the interface layer with the

number of cycles performed by the ALD and with the aperture-time of the precursors. This

analysis shows a base that will allow create hafnium oxide and titanium oxide nanofilms with

optimal characteristics.

[ ALD-422 ] ALD for the Development of Integrated Chemical

Sensors

Berni Manolo Pérez Ramos ([email protected]) 1 , Joel Molina Reyes 1

1 Departamento de Electrónica, Instituto Nacional de Astrofísica, Óptica y Electrónica,

Luis Enrique Erro 1, Tonantzintla, Puebla, México, 72000

The development driven by miniaturization in the electronics industry has raised the need for

technologies that enable film deposition thickness control at the atomic level. Also, the

requirements for the manufacture of structures with large aspect ratios make it necessary to

have deposition systems for production of very uniform and conformal films. This is why

atomic layer deposition (ALD) of films has become an essential tool for processing a wide

variety of materials in a wide range of different electronic applications. One area that has

taken advantage of ALD technology development is the manufacture of solid state chemical

sensors. This type of sensors employs dielectrics (usually metal oxides) to operate as ion-

sensitive gate materials. The presence of amphoteric sites on the surface of these dielectrics

makes the surface electrically charged due to adsorption of determining ions, and this in turn

causes a potential difference in the electrolyte-insulator-semiconductor system (EIS) which

can be detected, for example, as a change in the threshold voltage of a MOS transistor. All

these inorganic materials such as Si3N4, Al2O3, ZrO2, Ta2O5 and HfO2, can be processed by

ALD and are regularly employed in a wide variety of chemical sensors.

Specifically, the application of dielectrics deposited by ALD in solid state chemical sensors

provides significant advantages: manufacture of low-defect films, precise control of

thickness at the atomic scale, and conformal deposition on structures with a large aspect ratio.

Also, the self-limited sequential chemical reactions of the ALD process lead to highly

stoichiometric films that favor the generation of high densities of reactive sites on the

dielectrics surface, and improve the electrochemical sensor response. This is why we use

ALD dielectric films as sensitive areas in capacitive ion sensors (ISCAP) and extended gate

ISFET (EG-ISFET) sensors. Thin Al2O3 films (10nm) are deposited onto the gate sensitive

areas using TMA and water as precursor gases at a temperature of 250 °C. The chemical

characteristics of the films are determined by FTIR measurements, and a correlation has been




52

found between changes in the density of specific chemical bonds with temporal variations in

the sensitivity of these sensors. These devices have averages sensitivities of 54 [mVpH-1]

and 0.8 [pFpH-1], for EG-ISFETs and ISCAPS, respectively. In conclusion, the application

of films deposited by ALD, with all the advantages that this technology provides, allows us

to manufacture various kinds of chemical sensors with good sensitivity and stability

characteristics when compared to other reports.

[ ALD-423 ] ALD for development of Advanced Logical

Technology

Héctor Manuel Uribe Vargas ([email protected]) 1 , Joel Molina Reyes 1

1 INAOE

As the dimension of advanced electronic devices reach nanometric scales, high-k materials

(La2O3, Al2O3, HfO2) are used as gate oxides to achieve an EOT <1nm in state-of-the-art

Complementary Metal-Oxide-Semiconductor (CMOS) devices. These oxides need to have

some specific characteristics, such as low-deposit temperature (<300°C), a very accurate film

thickness (due to a small variation in the physical thickness could modify greatly the

electrical characteristics); a precise stoichiometry and a conformal deposition in 3

dimensions, which is the base for the new SOI technology (Partially Depleted and Fully

Depleted).

ALD technique fully complies with these characteristics, and that’s why is an important piece

in the continuous scaling of advanced electronic devices. For the particular case of Metal-

Oxide-Semiconductor Field-Effect Transistor (MOSFET) devices having nanometer

features, an exponential increase in its gate leakage current translates into continuous waste

of energy (in the form of overheating) which in turn, increases power consumption, also

present DIBL, which translates in a Vth shift and this is not desirable.

The heart of the MOSFET technology is the MOS capacitor and in this work, MOS capacitors

were fabricated using high-k gate oxides deposited with the Savannah-S100 of Cambridge

Nanotech ALD system. The gate oxides were HfO2 (4nm) and Al2O3 (10nm) which requires

the TDMAH and TMA precursors. Then, 40nm of aluminum were deposited as gate electrode

in ultra-high vacuum conditions using the Temescal BJD-1800 from Edwards E-beam

evaporation system.

Capacitors were electrically characterized in order to experimentally measure their

conduction properties regarding the gate leakage current. Experimental measurements of the




53

gate leakage current were compared with semi-empiric conduction models and with

simulations using Minimos NT.

Also 28nm MOSFET transistors (planar technology) were electrically characterized in order

to measure the gate leakage current and compare it with the devices fabricated at INAOE.

[ ALD-435 ] ALD for the Development of Emergent Non-

Volatile Memory Devices

Rene Valderrama ([email protected]) 1 , Joel Molina 1

1 Electronics Department, National Institute of Astrophysics, Optics and electronics

(INAOE), Tonantzintla, Puebla, 72000, Mexico.

FLASH memories had been in a technologic niche for a long time, but difficulties in their

scaling have led the research into resistive switching memories (ReRAM), which have a

simple structure (Metal-Insulator-Metal) therefore, they can be greatly scaled and integrated

into a three-dimensional arrangement. Due to the control at atomic level of the thickness and

the magnificent uniformity of the film, ALD (Atomic Layer Deposition) has emerged as a

crucial technique for the development of ReRAM memories. Here, the typical resistive

switching materials (RS) used are TiO2, NiO, ZrO2, HfO2, ZnO, Al2O3 [1]. They are the kinds

of materials that can be deposited easily by ALD. For the development of ReRAM memory

devices in INAOE, we have chosen HfO2 and Al2O3 as RS materials, because both are present

in commercial semiconductor devices, in addition, we take advantage of the low temperature

(<300°C) in the deposit process in order to study the possible integration of these memories

into the BEOL stage (Back-End of Line) of integrated circuits (ICs), which would increase

(at least one order of magnitude) the integration density. For the fabrication of these memory

devices (MIM structures), we have used Corning Glass and N-type Silicon wafers as

substrates. Tungsten and aluminum were deposited by E-beam Evaporation under ultra-high

vacuum conditions and they were used as metal electrodes. ALD system (Savannah-S100

from Cambridge Nanotech) is used to deposit ultra-thin layers of HfO2 and Al2O3, where

TDMAH and TMA along with H2O are the precursors for each condition respectively.

Photolithography and thermal treatments under different atmospheres are performed in order

to obtain final structures. From electrical characterization, resistive switching having a large

IOFF/ION relation as well as both unipolar and bipolar operation mode are shown in our

devices. Whit the latter we can conclude that, the ALD system allows us to development

emergent memory devices, which can be vertically integrated into the unexploited process

stages of the integrated circuits such as BEOL processing.

[1] R. Waser, R. Dittmann, G. Staikov, and K. Szot, Adv. Mater. 21, 2632 (2009).




54

[ ALD-443 ] IGZO transistors using HfO2 and Al2O3 as

dielectric layer by ALD

Eduardo Martinez-Guerra ([email protected]) 1 , Octavio

Luebbert-Larios 1 , Rodolfo Rodríguez Dávila 2 , Francisco Servando

Aguirre-Tostado 1 , Manuel A. Quevedo 2

1 Centro de Investigación en Materiales Avanzados, S.C.(CIMAV), Av. Alianza Norte #202,

Parque de Investigación e Innovación Tecnológica (PIIT), Nueva Carretera Aeropuerto

Km. 10, Apodaca, Nuevo León, México. C. P. 66600. 2 Department of Materials Science and Engineering, University of Texas at Dallas,

Richardson, Texas, 75080

Amorphous oxide semiconductors (AOS) have been widely investigated for flexible

electronics applications, such as flexible Thin Film Transistors (TFTs), due to their larger

field effect mobility in comparison with amorphous silicon TFTs, and also to the fact that

they can be obtained at room temperature [1]. Amorphous indium gallium zinc oxide (IGZO)

has several advantages among AOS, such as mobilities over 10 cm2/Vs and the possibility

to control carrier concentration with the variation of cations through the semiconductor [2].

We investigate the effect of oxygen Pressure on the electrical, optical and structural

properties of amorphous InGaZnO (a-IGZO) deposited by Puled Laser Deposition and RF

Ion Sputtering at room temperature. Films were prepared onto highly doped p-type silicon

<100>, glass and PET as substrates. The electrical resistivity and the carrier density showed

large variation with changes in the oxygen pressure. It was found a minimum resistivity for

those films deposited at 10 mTorr and a huge increment in those films deposited at 80 mTorr.

It was found by XRD that all films deposited at room temperature exhibit an amorphous

structure. On the other hand, the physical properties of the films like transparency, electron

mobility, and free-electron concentration were found to be correlated to the oxygen pressure

during the deposition and in turn to the possible oxygen vacancies or metallic interstitial in

the film. The energy gap estimated from the optical transmittance showed an increasing

tendency with increasing oxygen pressure. When carrier concentration was less than 1019 cm-

3, the temperature dependence of hall mobility showed thermally-activated behavior while

carrier concentration was independent of temperature, showed almost degenerated

conduction at Ne>1018 cm-3.

Films with better performance were used as active channel in TFT fabricated by shadow

mask and photolithography. For films deposited at low pressure, less than 20 mTorr,

transistors showed low ION/IOff ratio with high saturation current (ISat) which suggest low

resistivity. For those films deposited at pressures higher than 30mTorr, the ION/ IOff increase




55

up to 107 with ISat in range 10-3 to 10-5. Field Effect mobility is higher than 10 cm2/(V*s) for

those films with oxygen treatment. Our results suggest that oxygen pressure can be exploited

as key parameter to control the electrical and the optical properties of a-IGZO films deposited

by PLD and RF Ion Sputtering. Collagen is a biocompatible and biodegradable protein

abundant in mammals. This work also demonstrates the opportunity of using an Al2O3

dielectric layer on collagen substrate for new biosensor applications.

The authors gratefully acknowledge to The University of Texas at Dallas (UTD) through the

Flexible Electronics Research group headed by Dr. Manuel Quevedo for fruitful discussions

and technical facilities. The authors also thanks to N.Pineda, C. Leyva-Porras, L.G.Silva, E.

Longoria R. for their technical support.

[1] Kamiya, T., Nomura, K., & Hosono, H., Present status of amorphous In-Ga-Zn-O thin-

film transistors. Science and Technology of Advanced Materials, 2010. 11(4): p. 044305.

[2] Nomura, K., et. al., Room-temperature fabrication of transparent flexible thin-film

transistors using amorphous oxidesemiconductors. Nature, 2004. 432: p. 488-492.

[ ALD-489 ] Processing and Performance Simulation of

Advanced MOSFET and FinFET Devices based on Metal

Gate/High-k Materials

Omar López ([email protected]) 1 , Joel Molina ([email protected])

1

1 Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Grupo de

Microelectrónica. Tonanzintla, Puebla, 72840, México.

Processing and Performance Simulation of Advanced MOSFET and FinFET

Devices based on Metal Gate/High-k Materials

A simulation (CAD) analysis of advanced MOSFET devices is presented in this work, where

high k dielectric materials have been used as ultra-thin gate dielectrics. For these, the

deposition process of metallic oxides by atomic layer (ALD) instead of chemical vapor

deposition (CVD) represents a key step for device fabrication, this is, working with lower

processing temperatures compared to CVD method, as well as having an ideal conformal

deposition process in order to fully cover complex three-dimensional structures (with high-

aspect ratio) of an integrated circuit. The ALD method is quite compatible with the CMOS




56

advanced fabrication processing in order to deposit and/or process these materials while

maintaining their thermodynamic stability conditions (considering that after deposition of

these metallic oxides, the final devices are subjected to relatively high thermal treatments).

Some of these ALD materials are: Al2O3, ZrO2 and HfO2, and they are used in advanced

transistors like FD SOI-MOSFETs, FinFETs, etc. Using different structures for these oxides

the intention is to improve the carrier mobility in the advanced transistors channel and using

materials like Ge (for PFET channel) or III-V materials like InGaAs (for NFET channel). On

the other hand, use of high K dielectrics in MOSFETs has resulted in a reduction of the

equivalent oxide thickness (EOT), thus giving a better control of the OFF-ON states of

transistors. In state-of-the-art MOSFET devices, the EOT obtained is 20 Å (2nm). In this

work our simulations are developed in the Athena module for the design and virtual

fabrication of all deices; the Atlas module is also used for its characterization performance,

both belonging to SILVACO. Atlas allows us setting the metal’s effective work function

when used with these high k gate insulators; this is a charge neutrality level model, where

pre-set work function values can be used as well. From this work, it has been possible to

determine the main design parameters for advanced MOSFET devices, which are so

important in order to migrate from a planar MOSFET to a three-dimensional FinFET device.




57

Poster Session

[ ALD-206 ] Thickness Effect on the Optical, Morphological

and Physicochemical Properties in Al2O3/ZnO Nanolaminate

Thin Films Prepared by Atomic Layer Deposition

Javier López Medina ([email protected]) 1 , Jesús Martínez 1 ,

Noemí Abundiz 1 , David Domínguez 1 , Felipe Castillón 1 , Roberto

Machorro 1 , Mario H. Farías 1 , Hugo Tiznado 1

1 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México

In this work, we studied the optical, morphological and physicochemical properties in ultrathin

nanolaminate films based on bilayers of Al2O3/ZnO (AZ) deposited on Si (100) by thermal atomic

layer deposition (ALD) technique, changing the thickness between bilayers (0.1, 0.5, 1, 2, 5 and 10

nm). Through this technique it is possible to obtain control of the thickness of layers during the

growth, making this a self-limiting and self-controlling process to coating surfaces, which allows high

aspect ratio. Optical properties such as refractive index (n), extinction coefficient (k), broad bandgap

(Eg) and dielectric function (e) of each nanolaminate, were studied via spectroscopic ellipsometry,

and spectral reflectance UV – vis. The optical and electronic properties of nanolaminates are strongly

determined by its dielectric constant and therefore it is an important parameter to consider in order to

improve performance of electronic devices such as high - K dielectric constant capacitors. In order to

obtain information about the surface morphology and roughness parameters for the nanolaminates,

Atomic Force Microscopy (AFM) was used. Finally, we studied by X-Ray Photoelectron

Spectroscopy (XPS) to determine the chemical composition of the surface of each of the samples.

These kind of systems are considered materials with interesting technological applications in

nanotechnology, because it is expected that the combination of different dielectric materials in the

form of mixed oxides or nanolaminates, exhibit optical properties that enhance its dielectric response.

This behavior has great interest in nanoelectronics and optoelectronics.

Keywords: Nanolaminates films, Atomic Layer deposition, Dielectric Constant, high- K oxide films,

Optical properties.

Acknowledgements

This work was supported by research project PAPIIT - IN105114 and IN107715. J. López thanks

DGAPA for the postdoctoral fellowship position.




58

[ ALD-253 ] Design, assembly and control of an atomic layer

deposition system (ALD)

Hugo Leos Méndez ([email protected]) 1 , Pierre Giovanni

Mani González ([email protected]) 1 , Mario Eduardo Ruelas Corral 1 ,

Juan Francisco Hernández Paz 1 , Jose Trinidad Elizalde Galindo 1 , Jose

Rurik Farias Mancilla 1

1 Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, Universidad

Autónoma de Ciudad Juárez, Ave. Del Charro 450, Cd. Juárez. C.P. 32310, Chihuahua,

México.

The atomic layer deposition (ALD) is a technique of layer-by-layer growth at nano-metric

level in a controlled and highly accurate form. The purpose of this work is to describe the

basic features of the ALD system that is being built. The specific design of key parts of the

system allows to obtain certain fundamental properties during the cycle. The reactor is the

element that holds the growth process, also is the main stronghold of the structure. Made of

stainless steel, it features a design that allows optimize tasks that facilitate the accumulation

of cycles in the process. This has an input duct for the precursors and another for the output.

The growth zone of the films is at the center with a gap depth to prevent movement of the

product during the process. Just below the growth zone is found a hole which will hold a flat

circular resistance responsible to provide the required heat to the system. An important

feature to consider is the system protection against leakage during the cycle. This ALD

system has an O-ring in the reactor that provides a pressure seal that isolates the system of

large leaks. The skeletal of the system consists of pipe and stainless steel connectors with

standardized measures. To provide the low vacuum and purge required to the reactor during

the process is used a vacuum pump of medium power capable of providing a maximum

vacuum of 1 x 10 -4 tor. The use of electro-pneumatic valves 2/2 to control the flow of

precursors during the cycle. To control the system is used an embedded system Arduino

UNO. With a low cost and flexibility this controller uses a high-level language for creating

routines and subroutines with a specific purpose in the process. Capable of handling digital

inputs and outputs, also has a section aimed to analog inputs which allows to introduce

important variables for optimal control of the system such as temperature, pressure, flow, etc.

The ability to communicate with a platform of design and graphic control, such as Labview,

allows us to optimize and extend the control/monitoring of the ALD system.




59

[ ALD-270 ] Electrical characterization of Al2O3/ZrO2

nanolaminates



Nikola Radnev 2 , Mario Farías 1 , Hugo Tiznado 1




Abstract: With the density increase and the minimum feature size of dynamic random access

memory (DRAM), high-k dielectric materials in metal–insulator–metal (MIM) capacitor

have been investigated to obtain sufficient capacitance for refresh requirements. Metal-

Insulator-Metal capacitors, with ZrO2/Al2O3/ZrO2 (ZAZ) - nanolaminate thin-films as a

dielectric layer, exhibit reduced leakage currents compared to capacitors based on pure ZrO2

respectively. These systems providing a high dielectric constant suitable for DRAM

applications. ZAZ dielectric laminate grown by atomic layer deposition (ALD) has a mixture

of both crystalline and amorphous phases caused by the presence of ZrO2 and Al2O3 oxides

in order to coordinate the balance between capacitance and leakage current in the capacitor

performance. Although the crystallization of ZrO2 may induce the presence the leakage

current in the thin films, the dielectric constant of ZrO2 can be significantly enhanced, when

ZrO2 film it is remains in tetragonal phase (k=47), but the combination with another dielectric

that has higher bandgap as amorphous Al2O3 could avoid the leakage current in the material.

in addition, Al2O3 layer will produce capacitance loss due to its relatively lower dielectric

constant (∼9).

In this work, we studied the electrical properties in ultrathin nanolaminate films based on

bilayers of Al2O3/ZrO2 deposited on Si (100) by thermal atomic layer deposition (ALD)

technique, changing the thickness between bilayers (0.1, 0.5, 1, 2, 5 y 10 nm). Deposited

films were electrically characterized through measurements of the capacitance as a voltage

function. Also we made studies of current vs. voltage in order to obtain the electrical




Acknowledgments




60


CONACyT - 238402. The authors would like to thank Alex Tiznado, Enrique Medina,

Margot Sainz, Juan Peralta and Pedro Casillas.

References

1. Ming-Yen Li, Bin-Siang Tsai, Pei-Chuen Jiang, Hsiao-Che Wu, Yung-Hsien Wu,

Yu-Jen Lin, Thin Solid Films 518 (2010) 5272–5277

2. Dominik Martin, Matthias Grube, Wenke Weinreich, Johannes Müller, Walter

M.Weber, Uwe Schröder, Henning Riechert, and Thomas Mikolajick, JOURNAL OF

APPLIED PHYSICS 113, 194103 (2013)

3. D. Vanderbilt, X. Zhao, D. Ceresoli, Thin Solid Films 486 (2005) 125.

4. D.S. Kil, H.S. Song, K.J. Lee, K. Hong, J.H. Kim, K.S. Park, S.J. Yeom, J.S. Roh,

N.J. Kwak, H.C. Sohn, J.W. Kim, S.W. Park, Development of New

TiN/ZrO2/Al2O3/ZrO2/TiN Capacitors Extendable to 45nm Generation DRAMs

Replacing HfO2 Based Dielectrics, Honolulu, U.S.A., June 13–15, 2006, Symposium

on VLSI Technology, Digest of Technical Papers, , 2006, p. 38.

[ ALD-275 ] Electrical characterization of Y2O3/ZrO2

nanolaminates



Nikola Radnev 2 , Mario Farías ([email protected]) 1 , Hugo Tiznado 1




Abstract: Silicon dioxide (SiO2) has been used as the primary gate dielectric material in

field-effect devices since the advent of the first integrated circuit. However, this kind of

material has limitations when applied as gate dielectrics due to the exponential increase in

tunneling current with decreasing its thickness. Currently, different investigations carried to

improve the limitations caused for the silicon oxide thickness, have suggested the use of

several materials that can replace the SiO2. For example, gate dielectrics, such as Ta2O5,

TiO2, Y2O3, and ZrO2 can be used. Unfortunately, most of these materials are not thermally

stable on silicon. However, often occurs the possible formation of SiO2 or metal silicides

when these materials are deposited on silicon or during subsequent annealing. It is known




61

that SiO2 has a lower dielectric constant; therefore an underlying SiO2 layer can reduce the

effective capacitance of the film. Yittria-stabilized zirconia oxide (YSZ, with dielectric

constant 25–29.7), It is a material with interesting dielectric properties that can be used as

alternative gate dielectrics due to it is considered as one of the few materials that can be

thermodynamically stable in contact with silicon at 1000 K.

In this work, we studied the electrical properties in ultrathin nanolaminate films based on

bilayers of Y2O3/ZrO2 deposited on Si (100) by thermal atomic layer deposition (ALD)

technique, changing the thickness between bilayers (0.1, 0.5, 1, 2, 5 y 10 nm). Deposited

films were electrically characterized through measurements of the capacitance as a voltage

function. Also we made studies of current vs. voltage in order to obtain the electrical




Acknowledgments


CONACyT 238402. The authors would like to thank Alex Tiznado, Enrique Medina, Margot

Sainz, Juan Peralta and Pedro Casillas.

References

1. Roy P K and Kizilyalli I C 1998 Appl. Phys. Lett. 72 2835.

2. Campbell S A, Kim H S, Gilmer D C, He B,Ma T and GladfelterWL 1999 IBM J.

Res. Dev. 43 383.

3. Choi S C, Cho M H, Whangho SW, Whang C N, Kang S B, Lee S I and LeeMY 1997

Appl. Phys. Lett. 71 903.

4. Copel M, Gribelyyuk Mand Gusev E 2000 Appl. Phys. Lett. 76 436.

5. SJ Wang, Semicond. Sci. Technol. 16 (2001) L13–L16.




62

[ ALD-276 ] Study of the optical, electrical and

physicochemical properties in dielectric nanolaminate thin

films based on Al2O3/ ZrO2 prepared by Atomic Layer

Deposition

Javier A. López Medina ([email protected]) 1 , Jesús Martínez 1 ,

Noemí Abundiz 1 , David Domínguez 1 , Felipe Castillón 1 , Roberto

Machorro 1 , Mario H. Farías 1 , Hugo Tiznado ([email protected]) 1


Nanolaminates of different mixed oxides bilayers, exhibit high-K dielectrics constants that

makes them interesting materials for applications in microelectronics and optoelectronics. In

this work, we studied the optical, electrical, morphological and physicochemical properties

in ultrathin nanolaminate films based on bilayers of Al2O3 – ZrO2 (AZ) deposited on Si

(100) by thermal atomic layer deposition (ALD) technique, changing the thickness between

layers 0.1 to 10 nm). Through this technique it is possible to obtain the thickness control of

the atomic layers during the growth, making this a self-limiting and self-controlling process

to coating surfaces which allows high aspect ratio. Optical properties such as refractive index

(n), the extinction coefficient (k), bandgap (Eg) and the dielectric function (e) of each

nanolaminates, were studied via spectroscopic ellipsometry, and spectral reflectance UV –

vis. The optical and electronic properties of nanolaminates are strongly determined by its

dielectric constant and therefore it is an important parameter to consider in order to improve

performance of electronic devices such as high - K dielectric constant capacitors. In order to

obtain information about the surface morphology and roughness parameters for the

nanolaminates, Atomic Force Microscopy (AFM) was used. Finally, we studied by X-Ray

Photoelectron Spectroscopy (XPS) to determine the chemical composition of the surface of

each of the samples. These kinds of systems are considered materials with interesting

technological applications in nanotechnology, due it is expected that the combination of

different dielectric materials in form to nanolaminates exhibit optical properties that enhance

its dielectric response, this behavior have great interest in nanoelectronics.

Keywords: Nanolaminates films, Atomic Layer deposition, Dielectric Constant, high- K

oxide films, Optical properties.

Acknowledgements

This work was supported by research project PAPIIT - IN105114 and IN107715. J. López

thanks DGAPA for the postdoctoral fellowship position.




63

[ ALD-383 ] STUDY OF THE DIELECTRIC CONSTANT OF

HfO2 GROW BY ALD DETERMINED IN Ni/HfO2/c-Si MOS

STRUCTURES

Jorge Alejandro Torres-Ochoa ([email protected]) 1 , Zeus Montiel-

Gonzalez 1 , Yuri Lizbeth Chipatecua-Godoy 1 , Gustavo Gomez-Sosa 1 ,

Gabriela Molar-Velazquez 1 , David Salvador Garcia-Saleta 1 , Andres De

Luna-Bugallo 1 , Alberto Herrera-Gomez 1

1 CINVESTAV-QUERETARO

Hafnium oxide (HfO2) is nowadays widely employed in metal-oxide-semiconductor (MOS)

devices. Since the independent characterization of the interface layer is difficult, the precise

quantitative correlation between the structure of the device and the effective dielectric

constant still represent an open problem. In this work we evaluate the behavior of HfO2 films

grown on crystalline silicon (c-Si), both hydrogen-terminated and with a thin thermal oxide.

Nickel was employed as gate metal.

Hafnia films of different thicknesses (2, 4, 8 and 16 nm) were grown at 250 °C by atomic

layer deposition (ALD) using tetrakisdimethylamido hafnium and water as precursors.

Metallic Ni (200 nm) contacts are deposited using a sublimation system with base pressure

of ~5x10-8 Torr and working pressure of ~5x10-3 Torr. Angle resolved X-ray photoelectron

spectroscopy (ARXPS) measurements were carried out to determine chemical and structural

composition. Finally, MOS electrical properties were measured through C-V characteristics

to correlate the electric, structural and chemical properties of the Ni/HfO2/c-Si films.

Keyword: Hafnium, MOS device, dielectric constant.

[ ALD-401 ] Manufacture of a Growth Chamber for a ALD

equipment

María Magdalena Montsserrat Contreras Turrubiartes

([email protected]) 1 , José Nieto Navarro 1 , Edgar López Luna

1

1 Coordinación para la Innovación y Aplicación de la Ciencia y la Tecnología, Universidad

Autónoma de San Luis Potosí, Av. Sierra Leona #550, Col. Lomas 2a. Sección




64

In this work we present the fabrication for an ALD growth chamber. The design, selection of

the right materials and the subsequent manufacture of the necessary connections for proper

operation. The corresponding images of the process and the results are presented.

[ ALD-444 ] Crystallographic study of vertically aligned and

doped ZnO nanorods growth using textured ZnO films

produced by ALD

José Luis Cervantes 2 , Ricardo Rangel 2 , Eduardo Martínez-Guerra

([email protected]) 1

1 Centro de Investigación en Materiales Avanzados, S.C., Parque de Investigación e

Innovación Tecnológica (PIIT), Apodaca, Nuevo León, México. 2 Facultad de Ingeniería Química, Universidad Michoacana de S.N.H., Morelia,

Michoacán, México.

The synthesis of one-dimensional single crystalline ZnO nanostructures has been of

increasing interest due to their promising applications in nanoscale devices. Doped and

vertically aligned ZnO nanorod arrays with different aspect ratios were synthesized by hybrid

wet chemical route. In this study, it was possible to obtain vertically aligned ZnO nanorods

using a method that consists in two steps: i) the growing of a textured ALD film to grow a

ZnO seeded surface on glass and silicon single crystals ii) and the nanorod array growth by

hydrothermal synthesis. ZnO thin films are firstly produced by means of ALD deposited on

glass substrates. Subsequently a hydrothermal method is employed to grow vertical-aligned

doped-ZnO nanorod arrays on ZnO films. A textured ZnO layer with preferential direction

in the normal c-axes is formed on substrates by the decomposition of diethylzinc (DEZn) to

provide nucleation sites for vertical nanorod growth. Doped ZnO nanorods (ZnO-NRs)

growth over the substrates was performed by wet chemical procedure in which Zn(NO3)2

and hexamethylenetetramine were used as the main precursors. C6H9O6In, Ru3(CO)12 and

Ce(C2H3O2)3 • 1.5H2O compounds were used for doping. Crystallographic orientation of

doped ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis.

XRD results indicate that the nanorods are high-quality single crystals growing along [0001]

direction with a high consistent orientation perpendicular to the substrate which is quantified

through the texture coefficient. Composition, morphologies, length, size and diameter of the

nanorods were studied using a scanning electron microscope, energy dispersive x-ray

spectroscopy (EDS) analyses and atomic force microscopy (AFM). Length and thickness of

the ZnO-NRs ranged between 40 and 90 nm and 300 and 600 nm, respectively. It is

demonstrated that crystallinity of the ZnO-ALD films plays an important role on the vertical-

aligned doped ZnO nanorod growth. SEM images in plane and tilted view show that the




65

nanorods have smaller average diameters when compared with conventional hydrothermal

synthesis. The possible growth mechanism concerning the growth of the different doped ZnO

nanorods morphologies through the hybrid method is also discussed. The nanorod arrays

synthesized in solution had a diameter, length, density, and orientation desirable for a

potential application as nanostructured sensor devices and solar cells.

[ ALD-448 ] Fabrication of a flexible dye sensitized solar cell

using Atomic Layer Deposition

Manuel Meléndrez 2 , Francisco Solís-Pomar 4 , Miguel José Yacamán 3 ,

Eduardo Pérez-Tijerina 4 , Eduardo Martinez-Guerra


1 Centro de investigación en Materiales Avanzados (CIMAV), Unidad Monterrey-PIIT,

Apodaca, Nuevo León, México 66600. 2 Department of Materials Engineering (DIMAT), Faculty of Engineering, University of

Concepcion, 270 Edmundo Larenas, Casilla 160-C, Concepcion, Chile 4070409. 3 International Center for Nanotechnology and Advanced Materials (ICNAM), Department

of Physics & Astronomy, University of Texas at San Antonio, One UTSA Circle, San

Antonio, TX 78249, USA. 4 Universidad Autónoma de Nuevo León, Facultad de Ciencias Físico-Matemáticas, San

Nicolás de los Garza, Nuevo León 66451, México.

Flexible and rigid dye sensitized solar cells (flex-DSSCs) were built using hexagonal-shaped

small ZnO nanorods synthesized on PET (Polyethylene terephthalate)/ITO and Glass/FTO

substrates. In the synthesis, Atomic Layer Deposition (ALD) was used to deposit a textured

ZnO film which acts as seed layer. ZnO nanorods growth was carried out by a chemical

method assisted by ultrasound using Zn(NO3)2 and hexamethylenetetramine (HMT) as

precursors. The reaction was carried out in two steps: i) ZnO textured film deposition and ii)

ultrasound-assisted growth. After, synthesis, aligned ZnO nanorods (ZnO-NRs) with lengths

and thicknesses between (240-350 nm) and (25-80 nm) on substrates were obtained and

characterized by HRTEM, SAED, EF-SEM, UV-Vis and Raman spectroscopy. Structural

analysis revealed that the ZnO nanorods are well crystalline, possessing a perfect hexagonal

structure characteristic of Wurtzite zinc oxide with preferential growth in [0001] direction.

ZnO-NRs/(PET/ITO) and ZnO-NRs(Glass/FTO) transmittance ranged between 50% and

80%, this variation depended on the synthesis conditions. Optical band-gap of the

synthesized materials was approximately 3.3 eV and this value was independent of the

nanorods dimensions. Through EF-SEM, it is evidenced that the nanorods grew on ZnO seed

layer of 200 nm, which allowed good contact with the conducting surface of the substrate.




66

Analyses on the effect of synthesis parameters on NRs growth, fabrication of solar cell

prototype using working electrode and collector electrode were formed by (Glass/FTO/ZnO-

film/ZnO-NRs/ruthenium-dye) and (Glass/FTO/Pt-layer) respectively. Experimental details,

structural, electrical and optical characterization details are discussed.It is confirmed that

these nanorods synthesized by hybrid methods are single crystals of ZnO hexagonal wurtzite

type (also seen in the XRD). The observed planes have an inter-planar distance of 0.26 nm

corresponding to the (0002) plane. Atomistic models correspond to ZnONRs which are seen

from different zone axes. The UV–Vis spectra of glass/FTO/ZnO-ALD-film and

glass/FTO/ZnO-ALD-film/ZnO-NRs substrates were recorded. From the UV–Vis spectra, it

is observed that when the reaction times increased the percentage of transmittance decreased

owing to ZnO-NRs size (diameter and length) increase as well as the ZnO-film on glass/FTO

substrates. Higher reaction times both the nanorods size and the protective ZnO-ALD film

are greater, this leads to decrease the substrates transmittance and also loss on linearity at

energy values near the optical absorption due to increase in the light scattering phenomena.

Optical absorption edges of the films did not showed blue shift due to quantum size effect.

In addition, experimental results confirmed that the optical absorption depends mainly on the

ZnO-NRs deposited on the electrode more than the ZnO-ALD film absorption. Electrical

performance for flexible and rigid dye sensitized solar cells (flex-DSSCs) were developed

and it will be discussed through presentation.




67

[ ALD-497 ] Synthesis and characterization of TiO2 and HfO2

nanofilm compounds by ALD

Heber Hernández-Arriaga ([email protected]) 1 , Eliseo Garcia-

Ramirez 1 , Pierre Giovanni Mani-Gonzalez ([email protected]) 4 , Joel

Molina-Reyes 3 , Eduardo Martinez-Guerra 2 , Edgar Lopez-Luna 1 , Miguel

Angel Vidal-Borbolla 1

1 Centro de Aplicación de la Radiación Infrarroja, Energías Alternativas y

Materiales, Coordinación para la Innovación y Aplicación de la Ciencia y

la Tecnología, Sierra Leona 550, Lomas 2a. Sección, San Luis Potosí, C.P.

78210, San Luis Potosí, México 2 Centro de Investigación en Materiales Avanzados Monterrey, Alianza

Norte 202. Parque de Investigación e Innovación Tecnológica. Apodaca,

C.P. 66600, Nuevo León, México. 3 Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro

1, Tonantzintla, C.P. 72840, Puebla, México. 4 Instituto de Ingeniería y Tecnología, Departamento de Física y

Matemáticas, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro

450, Cd. Juárez. C.P. 32310, Chihuahua, México.

Hafnium Oxide (HfO2) and Titanium oxide (TiO2) films are being studied for their high-k

constant in CMOS applications. Atomic layer deposition (ALD) is a novel technique used to

deposit oxides, metals and nitrides with high quality and control thickness. Some applications

for HfO2 and TiO2 are optical coatings, sensors and MOSFETs. The HfO2-TiO2 nanofilm

compounds were synthetized through Tetrakis(dimethylamido)hafnium(IV) and

Tetrakis(dimethylamido)titanium(IV) as precursors and H2O as oxidant-agent varying

substrate temperature (120 °C, 200 °C and 250 °C). X-Ray Reflectivity (XRR) and

Spectroscopic Ellipsometry (SE) were used to determine HfO2 and TiO2 compound thickness

and dielectric function respectively. Stoichiometric films were studied with X-Ray

Photoelectron Spectroscopy (XPS). Leakage current and dielectric constant were studied

through I-V, C-V measurements respectively.




68

ADVANCED AND MULTIFUNCTIONAL

CERAMICS (AMC)

Chairman:

Jesus Heiras Aguirre (CNYN-UNAM)

Sesión Oral

[ AMC-81 ] Synthesis and characterization of

ferroelectric films polymer- ceramic composite (PMMA -

PZT, BZT,BNT)

Tonatiuh Escamilla Díaz ([email protected]) 1 , José Martín Yáñez Limón

([email protected]) 1 , Rafael Ramírez Bon 1

1 CINVESTAV Unidad Querétaro

There is currently a great interest in organic and inorganic hybrid materials due they present

very interesting structural, optical and electrical properties. Other materials of great interest

are the piezo – composites based in ferroelectrics, which consists of two phases: a matrix and

other dispersed. The effective properties depend on a variety of factors such as chemical

composition, distribution, microstructure, etc. and they are a function of the constituent

phases.

In this work we synthesized hybrid materials films of PMMA – TiO2 - PZT, by sol-gel, which

is a quite convenient method to prepare this class of materials. It is possible obtain a high

control of the chemical composition of the hybrid at low temperatures and a large area. The

films were deposited on glass for optical characterization, and ITO-glass for electrical

measurements. Methods for depositing the hybrid materials were spin coating and dip

coating. In case of spin – coating the speed was 1500rpm during 1 minute, on the other hand

the speed for dip coating was 6cm/min.

Similarly composite thin films were synthesized with a matrix of PMMA - TiO2 plus an

aggregate of PZT particles at different concentrations. Structural characterization, optical and

electrical were also performed using different techniques such as X-ray diffraction (XRD),

scanning electron microscopy (SEM), UV-VIS spectroscopy, etc.

The purpose of this study was to evaluate the optical and dielectric properties at different

concentrations in volume in the case of hybrid materials. That at low concentrations resulting




69

PZT, between 10 and 30%, they have poor optical properties, whereas at high (50 to 60%)

concentrations improve their properties.

In the case of composite material PMMA – TiO2 with PZT particles the aim it is to evaluate

its ferroelectric and dielectric properties, between dielectric and ferroelectric phase with

different PZT concentrations: 0, 2.5, 5, 7.5 and 10% by weight . Best results have been

observed in films deposited by dip-coating in both uniformity and dispersion of the particles

with size between 80 and 90nm. Also interesting results have been observed in the hysteresis

loops measured at different electric fields and polarization increases according increases the

field due to the influence of PZT´s particles.

[ AMC-214 ] Effect of CdO in the structure and optical

properties of germanate-tellurite glasses

Carlos Guadalupe Pérez-Hernández 3 , María Elena Zayas 4 , Josefina Alvarado-Rivera

([email protected]) 2 , David Alejandro Rodríguez-Carvajal 3 , María Betsabé

Manzanares-Martínez 3 , Mario Enrique Álvarez 3 , Rosendo Lozada-Morales 1

1 Benemérita Universidad Autónoma de Puebla, Postgrado en Física Aplicada, Facultad de

Ciencias Físico-Matemáticas, Av. San Claudio y Av. 18 Sur, Col. San Manuel, Ciudad

Universitaria, Puebla, Pue C. P. 72570, México. 2 Cátedras Conacyt, Departamento de Investigación en Física, Universidad de Sonora,

Blvd. Encinas y Rosales S/N, Col. Centro, C. P. 83000, Hermosillo, Sonora, México. 3 Departamento de Física, Universidad de Sonora, Blvd. Encinas y Rosales S/N, Col.

Centro, C. P. 83000, Hermosillo, Sonora, México 4 Departamento de Investigación en Física, Universidad de Sonora, Blvd. Encinas y

Rosales S/N, Col. Centro, C. P. 83000, Hermosillo, Sonora, México.

Germanate and tellurite glasses are widely known materials for its applications in

telecommunications and mid-infrared fibers. These oxides display properties like high linear

and nonlinear index, broad band transmission from the visible into the infrared, low phonon

energy, high refractive index, which are very desirable for IR technologies, non-linear optics

and design of laser devices. In this work, glasses from the novel CdO-TeO2-GeO2 ternary

system are investigated. A set of samples varying the cadmium oxide content from 10 to 80%

wt was fabricated by conventional melt-quenching method at 1350°C. Glasses of different

colorations from yellowish to brilliant orange were obtained, the later corresponded to the

glass with the highest content of cadmium oxide. X-ray diffraction results demonstrated the




70

amorphous nature of the samples and evidenced that only two glasses presented partial

crystallization of CdTeO3 and Cd3 Al2 (GeO4)3 phases. Infrared spectra analysis shows the

characteristic absorption peaks of GeO6 (520-470 cm -1) and Cd-O (440-420 cm-1) bonds

vibration; and in the range of 800-600 cm-1 a broad and weak band related to Te-O-Te bonds

vibration. Raman spectra displays two main bands at 980-670 cm-1 and 640-370 cm-1, which

are related to stretching vibrations Te-O of TeO4 units and Ge-O-Ge bonds in 4- and 3-

membered GeO4 rings, respectively. CdO is a modifier oxide that will influence structural

changes in the glass matrix, this effect is noticed in the shift to lower wavenumber values of

the band at 980-670 cm-1 corresponding to TeO3/TeO3+1 units. For a more thorough analysis

of the structural changes, X-ray photoelectron spectroscopy of the glasses with the lowest

and highest contents of cadmium oxide was performed. High resolution analysis of the O 1s,

Ge 3d, Cd 3d and Te 3d photoelectron lines was realized to determined changes in

coordination and oxidation states of the cations. Moreover, non-bonding and bonding oxygen

ratio of the glasses was estimated. Finally, optical absorption spectra of the glasses and

estimation of the energy band gap of all samples were carried out. Results show that as the

content of CdO increase the energy band gap of the glasses decrease.

[ AMC-269 ] Influence in luminescence of type of doped

in perovskite.

María Dolores Durruthy-Rodriguez ([email protected]) 1

1 CINVESTAV-Querétaro, IPN, Libramiento Norponiente 2000, Fracc. Real de Juriquilla,

CP 76230, Santiago de Querétaro, Querétaro, México. Applied Physic Department,

Cybernetic, Mathematics and Physics Institute, CITMA, 15 # 551, Vedado, La Habana,

Cuba,

The ferroelectric materials have been recognized by their multifunctional physical properties;

inside them, their optic properties are investigation object due to their possible applications,

the photoluminescence is a very interesting phenomenon that appears in these materials.

In this work interesting results are presented from the luminescent emission to room

temperature of perovskitas ABO3, in the systems doped PZT and KNN, in A and B site of

the structure. The main emission bands in PZT appear around 1.73, 1.87, 2.5, 2.66 and 3.03

and at 1.86, 2.19, 2.31 and 2.5 eV for the system KNN, the excitement bands in all the cases

were 373, 457, 500 and 680 nm. The so much voltages of the lamp were measured like of the

samples to the different longitudes of excitement wave. The perovskitas free of lead presents

a promissory increment of the luminescent emission.




71

[ AMC-292 ] Nanostructured cerium oxide thin films

deposited by ultrasonic spray pyrolysis.

Mario Fidel García Sánchez ([email protected]) 2 , Ismael Ponce Rosas 1

, Guillermo Santana Rodríguez 1 , Betsabée Marel Monroy Peláez 1

1 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México.

A.P. 70-360, Coyoacán, C.P. 04510, México D.F. 2 Unidad Profesional Interdisciplinaria de Ingeniería y Tecnologías Avanzadas, Instituto

Politécnico Nacional, Av. IPN No 2580, Gustavo A. Madero, C.P. 07340, México D.F.

Nanostructured thin films of cerium oxide have been prepared on single-crystalline silicon

substrates by ultrasonic spray pyrolysis using cerium acetylacetonate as metallo-organic

precursors dissolved in anhydrous methanol. The morphology, structure and electrical

properties were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM),

atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), ellipsometry, and

impedance spectroscopy (IS). The substrate temperature was optimized for obtaining smooth,

dense and homogeneous nanocrystalline films with grains sizes as small as 10 nm. XPS

measurements shows a mix of Ce4+ and Ce3+ into the as grown samples, regardless of the

substrate temperature. The influence of thermal annealing on structural properties of films

was evaluated. The small grain size decrease the activation energy and the conductivity of

these obtained materials.

Acknowledgements

This work has been partially supported by IPN with research project 201500044. The authors

want to thank to C. Flores, O. Novelo, J. Romero, L. Lartundo and J. A. Andraca for technical

assistance.

Keywords: ceria thin films, nanostructure, ultrasonic spray deposition.




72

[ AMC-329 ] Synthesis of lanthanum nickelite based

perovskite by mechanosynthesis and urea combustion

methods

Luis Alberto Mendoza de la Rosa ([email protected]) 2 ,

Antonia Martínez Luévanos ([email protected]) 2 , Martín A.

Hernández Landaverde 1 , Sergio J. Jiménez-Sandoval 1 , Brenda R. Cruz

Ortiz 2

1 Cinvestav-IPN; Unidad Querétaro 2 Materiales Cerámicos; Universidad Autónoma de Coahuila; Blvd. V. Carranza s/n, Rep.

Ote., Saltillo, Coah. México. CP 25280

In this work the synthesis of lanthanum nickelite (La1-xMxNiO3±δ) by the methods of

mechanosynthesis and urea combustion was investigated. The characterization technique of

X-ray diffraction was used to evaluate the effect of temperature and thermal treatment time

on perovskite formation and on its purity. According to the XRD patterns of the samples

obtained by mechanosynthesis, the better result was obtained at 900 ° C, using a time of 10

hours; in the other hand, by combustion method it found that the perovskite phase was

obtained at 900 °C, but using a time of 5 hours. The best result was obtained by the urea

combustion method.




73

[ AMC-335 ] Evaluation of Corrosion on Borided and

Non-borided alloy Co-Cr-Mo ASTM F75 immersed in

Hanks’ solution.

Maria Guadalupe Rosas Becerra ([email protected]) 1 , Ivvone

Mejía Caballero 1 , Jose Martinez Trinidad ([email protected]) 1 ,

Manuel Palomar Pardave 2 , Ivan Enrique Campos Silva 1

1 Instituto Politécnico Nacional, Grupo Ingeniería de Superficies, SEPI-ESIME, U.P.

Adolfo López Mateos, Zacatenco, 07738 México, DF, México 2 Universidad Autónoma Metropolitana, Av. San Pablo No. 180, Azcapotzalco, 02200

México, DF, México

The corrosion resistances of borided and non-borided cobalt alloy immersed in a simulated

body fluid were evaluated in this study. The boriding process was performed using the

powder-pack method at a 1223 K with 6 h of exposure. The corrosion tests were assessed

using Potentiodynamic Polarization technique, in which the samples were evaluated during

10 days of inmersed in the Hanks’ solution. After the tests, borided and non-borided samples

were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray

Spectrometry (EDS) to determine the corrosion mechanisms and the chemical composition

over the surfaces, respectively.

According to the polarization resistance curves, the boride cobalt alloy provided a reasonable

corrosion resistance notwithstanding, the non-borided cobalt alloy exhibited higher

resistance value. The main corrosion mechanism was pitting corrosion observed on the

borided cobalt alloy by SEM technique and the principal of alloy elements of boronized

samples from surface was determined using EDS. It was concluded that the decrease of

corrosion resistance of boride cobalt alloy was caused by presence of sulfates and phosphates

over the materials surface, which were contained in provides the Hanks’ solution.




74

INVITED TALK

[ AMC-484 ] Second harmonic generation in Lithium

Niobate nanoparticles

Oswaldo Sanchez Dena 1 , Emma García-Ramírez 1 , Jose Trinidad

Elizalde-Galindo 3 , Pierre Giovanni Mani-Gonzalez 3 , Enrique Vigueras-

Santiago 2 , Jorge Alejandro Reyes-Esqueda 1 , Rurik Farías


1 Instituto de Física, Universidad Nacional Autónoma de México, 04510, México, D. F.,

México 2 Laboratorio de Investigación y Desarrollo de Materiales Avanzados, Universidad

Autónoma del Estado de México, Paseo Colón esquina Paseo Tollocan, Toluca, Estado de

México, 50000, México 3 Universidad Autónoma de Ciudad Juárez, Av. Del Charro 450 Norte, Ciudad Juárez,

Chihuahua, 32310, México

We study second harmonic generation (SHG) in lithium niobate (LiNbO3) nanoparticles as a

function of the fundamental wavelength (800-1300 nm) and polarization angle. LiNbO3

nanocrystals were synthesized by means of a mechanochemical reaction using lithium

carbonate and niobium oxide; three different samples were obtained by this method. Structure

as well as composition of all the samples was verified by means of non-destructive

characterization techniques such as X-Ray Diffraction (XRD) and Raman spectroscopy.

Results of SHG show a maximum conversion efficiency of 1.37%, which corresponds to the

harmonic intensity at a fundamental wavelength of 1070 nm, also was not found a clear

dependency upon polarization angle of the incident light.




75

Sesión Poster

[ AMC-37 ] Hot corrosion analysis of NiCoCrAlY/7YSZ

coatings deposited by air plasma spray (APS) on a nickel

based superalloy

Nathalia Diaz Vallejo ([email protected]) 2 , Oscar Sanchez 2 , Julio

Cesar Caicedo 3 , William Aperador 1 , Gustavo Zambrano 2

1 Departament of Engineering, Universidad Militar Nueva Granada, Bogotá-Colombia 2 Thin Films Group, Department of Physics, Universidad del Valle, Cali-Colombia

3 Tribology, Powder Metallurgy and Processing of Solid Recycling Research Group,

Universidad del Valle, Cali-Colombia

In this study, hot corrosion performance and the damage mechanism of air plasma-sprayed

(APS) yttria-stabilized zirconia (YSZ) in contact with corrosive salts (vanadium pentoxide

V2O5 and sodium sulfate Na2SO4) were investigated at 700°C evaluated using

electrochemical impedance spectroscopy (EIS) and Tafel analysis. The EIS data were

interpreted based on proposed equivalent electrical circuits using a suitable fitting

procedure elaborated by Echem Analyst™ Software. The EIS spectra were fit to the

traditional model for metal coated with a porous, non-conductive coating where the

capacitors were replaced with constant-phase elements. The impedance measurement of YSZ

ceramic at 700°C in this test gives impedance spectra with a single semicircle. The resistance

of YSZ coat comes from the contribution of the YSZ grain. Phase transformations

and microstructural development were examined using X-ray diffraction (XRD), with

Rietveld refinement for quantitative phase analysis, and scanning electron microscopy

(SEM) that indicated that the reaction between sodium vanadate (NaVO3) and yttrium

oxide (Y2O3) produces yttrium vanadate (YVO4) and leads to the transformation of tetragonal

to monoclinic zirconia phase.




76

[ AMC-88 ] Effect of thermal treatment on the

luminiscence of Eu3+ doped ZnO-CdO-TeO2 glasses

Iveth Viridiana García Amaya ([email protected]) 3 , María

Elena Zayas Saucedo 4 , Josefina Alvarado Rivera 2 , Mario Enrique Álvarez

Ramos 3 , Rosendo Lozada Morales 1

1 Benemerita Universidad Autónoma de Puebla, Postgrado en Física Aplicada, Facultad de

Ciencias Físico-Matemáticas, Avenida San Claudio y Avenida 18 Sur, Colonia San

Manuel, Ciudad Universitaria, 72570 Puebla, PUE, México 2 Cátedras Conacyt, Departamento de Física, Universidad de Sonora, 83000 Hermosillo,

SON, México 3 Departamento de Física, Universidad de Sonora, 83000 Hermosillo, SON, México

4 Departamento de Investigación en Física, Universidad de Sonora, 83000 Hermosillo,

SON, México

A series of europium doped glasses in the ternary system 10ZnO·30CdO·60TeO2 have been

synthetized by the conventional melt-quenching method at 1000°C by 30 minutes, varying

the concentration of europium nitrate (Eu(NO3)3.6H2O) from 0.3 to 1.5 % mol. In this work

a study of the optical and structural differences of the as-cast and heat-treated glasses is

presented. The structural studies reveal the presence of amorphous phase for both set of

samples detected by DRX. FT-IR spectra of the as-cast glasses shows the decomposition

of TeO4 units in TeO3+1/TeO3, while in the heat-treated glasses the TeO4, units are

reconstituted. This effect can be probably caused by the reincorporation of O2 molecules

trapped in the interstices into the glass matrix. The intensity of the band localized around

1556 cm-1 in Raman spectra decrease considerably after the thermal treatment..

Photoluminescence spectra of both set of glasses exhibit emissions from the transition of

Eu3+ ion: 5D2→7F0 (468 nm), 5D2→

7F2 (490 nm), 5D2→7F3 (511 nm), 5D1→

7F1 (536 nm), 5D1→

7F2 (554 nm), 5D0→7F0 (579.5 nm), 5D0→

7F1 (592 nm), 5D0→7F2 (613 nm), 5D0→

7F3

(652 nm), y 5D0→7F4 (490 nm). It is noticeable, the presence of the band associated with the

5D0→7F0 transitions, which it is only permitted when Eu3+ ions are occupying positions of

low symmetry. This, together with the fact that the band corresponding to the transitions 5D0→

7F2 dominated the emission spectra, excludes the possibility that it Eu3+ ions are in a

position of high symmetry.




77

[ AMC-228 ] STRUCTURAL STUDY AND

PHOTOLUMINESCENCE OF Cd3Al2Ge3O12 PHASE

IN GLASSES OF CdO-TeO2-GeO2 SYSTEM

Carlos Guadalupe Pérez Hernández ([email protected]) 1 ,

Josefina Alvarado Rivera ([email protected]) 1

1 Unison

A series of glasses of the CdO-TeO2-GeO2 system varying CdO and GeO2 composition were

fabricated. Reagent grade oxide powders of high purity were used for glass preparation by

melt-quenching method in high alumina crucibles at 1350°C. Some of the obtained glasses

presented crystallization of a white phase identified by XRD as a cadmium-aluminum

germanate (Cd3Al2Ge3O12). The formation of this compound is attributed to the crucible

corrosion during fusion leading to an incorporation of aluminum in the melt. It was

previously reported that the cadmium-aluminum germinate doped with Dysprosium

displayed phosphorescence under UV light excitation. In this work, a structural study and

luminescence properties of the cadmium-aluminum germanate were studied by means of X-

ray diffraction (XRD), Raman spectroscopy and photoluminescence. XRD confirmed the

formation of this phase in the samples with higher contents of cadmium oxide. Raman

spectroscopy was performed with both 488 and 632 nm laser lines, it revealed that the

material is excited with the red laser and shows a wide emission band in the infrared region.

Photoluminescence measurements were carried using a UV excitation light of 254 nm.

Results show that the emission chromatic coordinates are located near the white light region

in the CIELAB chromaticity diagram. This material has potential applications as white-light

emitting diodes.




78

[ AMC-305 ] Influence of La doping in multiferroic

properties of LiNbO3 nanoparticles

Carlos Alejandro Diaz Moreno ([email protected]) 2 , Abel Hurtado-

Macias 1 , Jorge Portelles 3 , Jesús Heiras 4 , Enrique Ramirez 2 , Jorge Lopez

2

1 Centro de Investigación en Materiales Avanzados S.C., Laboratorio Nacional de

Nanotecnología, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua,

Apdo. Postal 31109 México 2 Department of Physics of University of Texas at El Paso, 500 W. University Ave, El Paso

TX 79968 3 Facultad de Física, Universidad de La Habana, San lázaro y L, 10400, Cuba

4 Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología,

Km 107 Carretera Tijuana-Ensenada, Ensenada, B.C. 22860

In this work we reported an enhancement of the ferroelectric and ferromagnetic properties

when LiNbO3 doped with lanthanum. Lithium niobate doped with lanthanum

(La0.05Li0.85NbO3) was prepared by mechanical milling method using lithium carbonate,

niobium oxide and lanthanum oxide as precursors [1]. After 12 hours of alloying, the sample

was calcinated at 900ºC in order to remove carbonate residues. A second milling of 8 hours

was done to reduced particle size obtaining an average size of 70±5 nm. Result from X-ray

diffraction indicates the formation of ferroelectric phase obtained in air atmosphere with

spherical shape as confirmed by TEM micrographs. Raman and X-ray fluorescence

spectroscopy were performed in order to indicate new vibrations modes and elemental

analysis quantification respectively. To investigate the ferroelectric properties, the

nanoparticles were binded with PVA and pressed at 105 kg/cm2 to conform pills with a

diameter of 11.7 mm and a distance between plates of h=1 mm. The ferroelectric properties

were obtained at room temperature using a RADIANT RT-66ª equipment. The hysteresis

loops show a Ps= 0.235 μC/cm2, Pr= 0.141 μC/cm2 and Ec= 1.35 kV/cm values for

La0.05Li0.85NbO3 sample. And the values for Ps= 0.0701 μC/cm2, Pr= 0.0382 μC/cm2 and Ec=

391 kV/cm when compared to pure lithium niobate. The ferromagentic curves, measured in

a 9T Quantum Design VSM PPMS at room temperature. The measured mass sample was of

24.3 mg for both samples. The values for saturation magnetic moment are of 2.5 × 10−3 emu

for La0.05Li0.85NbO3 and 1.4 × 10−3 emu when compared to pure lithium Niobate.

[1] Díaz-Moreno, C.; Farias, R.; Hurtado-Macias, A.; Elizalde-Galindo, J.; Hernandez-Paz,

J. Multiferroic response of nanocrystalline lithium niobate. J. Appl. Phys. 2012, 111,

doi:10.1063/ 1.3673434.




79

[ AMC-341 ] Thermal Stability and Sinterability of

Ce0.8Sm0.2O2- δ, Ce0.8Sm0.15Ca0.05O2-δ and

Ce0.8Sm0.19Cu0.01O2-δ ionic conductors

César Gustavo Mendoza Serrato ([email protected]) 1 , José Ortiz

Landeros 1 , Carlos Gómez Yáñez 1

1 Departamento de Ingeniería en Metalurgia y Materiales Escuela Superior de Ingeniería

Química e Industrias Extractivas, IPN, UPALM Av. Instituto Politécnico Nacional S/N CP

04510, México D.F.

Ceria-based ceramic oxides are utilized as automotive exhaust catalysts, as catalysts in fuel

cells and as cathode, anode, and electrolyte materials in solid oxide fuel cells among others

[1-2]. The present work is a detailed study on the preparation and characterization of a series

of Ceria-based ceramic materials having ionic conductivity properties at intermediate

temperatures between (700-900 ° C). In this sense, materials with chemical formula of

Ce0.8Sm0.2O2-δ, Ce0.8Sm0.15Ca0.05O2-δ and Ce0.79Sm0.2Cu0.01O2-δ were synthesized by the

citrate complex precursor method and then were subjected to thermal and chemical stability

tests under CO2 rich atmosphere.

The structural and microstructural characterization of the different samples was conducted

by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), scanning electron microscopy

(SEM), thermogravimetric analysis (TGA) and ionic conductivity measurements. The

thermal stability study was conducted under a CO2 atmosphere at high temperature (900-

1300 oC).

The results suggest the effectiveness of citrate precursor method to incorporate the dopant

(Ca+2, Cu2+) in the fluorite structure of the Ceria. Additionally, results show a remarkable

effect of doping on both, the ionic conductivity, and stability properties. For example, it was

observed that incorporation of Ca2+ in the material increases the ionic conductivity values

and sinterability properties thereof. On the other hand the addition of Cu2+ cation has an effect

on the microstructural features of the material by reducing the mean grain size obtained after

sintering process.

[1] Masatomo Yashima, Some recent developments in the atomic-scale characterization of

structural and transport properties of ceria-based catalysts and ionic conductors, Catalysis

Today, 253 (2015) 3-19.

[2] F. Rahmawati, W. Fajriati, E. Heraldy, D. Gustaman-Syarif, Oxygen Ion-Conductivity

and Chemical Stability of Ceria Based-Electrolyte in Composite with Sodium Carbonate as

Electrolyte for Direct Biodiesel-Fuel Cells, Procedia Chemistry, 14 ( 2015) 164-170.




80

[ AMC-392 ] CO2 sorption-desorption analyses on

different of Li2O-Bi2O3 ceramics

Eva Marina Briz Lopez ([email protected]) 1 , Jose Ortiz

Landeros 1 , Issis Caudette Romero Ibarra 2 , Cesar Gustavo Mendoza

Serrato 1

1. Departamento de Ingeniería en Metalurgia y Materiales, Escuela Superior de Ingeniería

Química e Industrias Extractivas, IPN, Av. Instituto Politécnico Nacional s/n, CP 07738

México DF, México

2. Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, México

D.F., México. Av. San Rafael Atlixco # 186 Col. Vicentina C.P. 09340

Ceramic sorbents from the Li2O-Bi2O3 system have been studied as potential CO2 captors.

In the present research, ceramic sorbents were synthesized by the conventional solid state

reaction method. The different sorbents were synthesized from Bi2O3 and Li2O oxides and

completing the reaction between oxides in dry air stream at 700 ° C. The influence of the

different experimental conditions, such as temperature and CO2 partial pressure on the CO2

absorption capacity, were studied. The structural and microstructural characterization of

materials was conducted by X-ray diffraction (XRD) and scanning electron microscopy

(SEM) techniques. Furthermore, the CO2 absorption capacity and reaction rate as well as

thermal stability of the different materials were evaluated by thermogravimetric analysis

(TGA).

The obtained results showed the obtaining of the pure phase of differents lithium bismuthates

Li7BiO6, Li5BiO5, Li3BiO4 and LiBiO3. Specifically, Li7BiO6 shows a theoretical CO2

capture of 9.8 mmolCO2 g-1 in a temperature range of 275 to 575 ° C. Additionally, Li7BiO6

shows the capability to capture CO2 at very low CO2 partial pressure values.

[1] M. J. Ramírez-Moreno, I. C. Romero-Ibarra, J. Ortiz-Landeros, H. Pfeiffer, Alkaline and

alkaline-earth ceramic oxides for CO2 capture, separation and subsequent catalytic chemical

conversion. In: Claudia do Rosario Vaz Morgado and Victor Paulo Pecanha

Esteves, editors, CO2 Sequestration and Valorization, InTech Open Acces; 2014.

[2] Ke Wang, Pengfei Zhao, Xin Guo, Yimin Li, Dongtai Han, Yang Chao; Enhancement of

reactivity in Li4SiO4-based sorbents from the nano-sized rice husk ash for high-temperature

CO2 capture; Energy Conversion and Management; 2014.




81

[ AMC-459 ] Structure and optical studies of perovskite

Bi2Fe2Ga2O9

V. L. Medina-Llamas ([email protected]) 1 , M. F. Jasso-

Jasso 1 , J. J. Ortega-Sigala 1 , F. Puch-Ceballos 1 , A. Puga 1 , L. Pérez-

Arrieta ([email protected]) 1

1 Unidad Académica de Física. Universidad Autónoma de Zacatecas. Calz.

Solidaridad Esq. Paseo La Bufa s/n. C. P. 98060. Zacatecas, Zac.

The phase diagram of system pseudo-ternary (Bi2O3–Fe2O3-Ga2O3) provides

condition of composition and temperature for the growth of single crystal such as

BiFe1/2Ga1/2O3 and Bi2Fe2Ga2O9. In this work a single crystals of Bi2Fe2Ga2O9 of

perovskite structure were grown with dimensions greater than 1 mm from a Bi2O3 flux

by Crystal Growth from High-temperature Solutions Method. It is known that

Bi2Fe2Ga2O9 mixed oxide crystals have a habit and orthorhombic symmetry (Pbam).

However, we obtained crystals of brown-dark color with monoclinic habit in the same

conditions reported for other authors. The X-ray diffractometry method was used in

this compound in powder form to refine the structure by the Rietveld method. The

monoclinic structure parameters obtained are: a = 9.739 Å, b = 11.941 Å, c = 7.122 Å

and beta = 93.382o Å, V = 826.80 Å3, and Space grupo P2/m. Structural data already

published are compared with our results, also measurement results by means of optical

and electron microscopy are presented.




82

[ AMC-465 ] Structural and morphological

characteristics of compounds in the partial phases

diagram of Bi2O3–Fe2O3–Ga2O3 system

B. Villaneda-Saldívar ([email protected]) 2 , J. J. Araiza-Ibarra 2 , A.

B. Soto-Gúzman 1 , E. García-Jaramillo 2 , A. Puga 2 , L. Pérez-Arrieta


1 Departamento de Física. CINVESTAV-IPN. Av. Instituto Politecnico Nacional 2508,

Delegación Gustavo A. Madero, Col.San Pedro Zacatenco,C. P. 07360 Ciudad de México,

D.F. 2 Unidad Académica de Física. Universidad Autónoma de Zacatecas. Calz. Solidaridad

Esq. Paseo La Bufa s/n. C. P. 98060. Zacatecas, Zac.

Novel ferroelectric materials base on oxides Bi2O3 are specially important due to the electric

and magnetic properties they exhibit and make them useful to as a data storages devices. In

this work, we search for the powder formation of Bi2(Fe1/2Ga1/2)O3 (BFGO). The typical

temperatures, structural and morphological characteristic in Bi2O3–Fe2O3-Ga2O3 pseudo-

ternary phase diagram were evaluated with high-purity starting materials. The synthesis

starting from a simple oxides is carrying out by applying the Solid State Chemical Reaction

method. We focus in partial region of mole composition from 90:5:5 to 50:25:25. The X-ray

diffraction of samples demonstrated the presence of different phases based in Bi2O3 ( and

) and perovskites structures analogous to BiFeO3 (113) y Bi2Fe4O9 (249) when are doped

with Ga+3, Bi(Fe1/2Ga1/2)O3 y Bi2Fe2Ga2O9. Differential thermal and thermo-gravimetry

analysis (DTA-TGA) data makes it possible to present phase changes in the sample when the

temperature and chemical compositions is changed. Finally scanning electron microscopy

shows the morphological changes in the crystals. The sintered specimen with 11.5 mol %

Fe2O3 and 11.5 mol % Ga2O3 in the Bi2O3-Fe2O3-Ga2O3 system showed a 113-phase in its

as-sintered specimen.




83

[ AMC-473 ] CeO2-based mixed oxides for the catalytic

soot combustion for diesel engines

Wendy Téllez-Salazar ([email protected]) 1 , José Ortiz-Landeros

([email protected]) 1 , César Mendoza-Serrato 1 , Carmen Mertínez-Mancilla

1 , Heriberto Pfeiffer 1

1 Departamento de Ingeniería en Metalurgia y Materiales Escuela Superior de Ingeniería

Química e Industrias Extractivas, IPN, UPALM Av. Instituto Politécnico Nacional S/N CP

04510, México D.F

Diesel engines have high energy efficiency, but emit particulate carbonaceous material

commonly known as soot, which is responsible for severe issues of environmental pollution

and health damage. For example, such a material may be causing the development of cancer,

cardiovascular and respiratory effects as well as air, water and soil pollution [1].

The technology of particle filters, in combination with oxidation catalysts appears to be one

of the most efficient techniques for treating this issue. The challenge is to find a catalyst in

which soot combustion takes place at a lower oxidation temperature. Several types of

catalysts for soot combustion have been extensively studied. Catalysts containing precious

metals, alkali metal oxides, perovskites and most recently ceria-based catalyst are examples

of the aforesaid. In fact, the metal oxides based on ceria have been widely used as oxidation

catalysts due to its oxygen storage capacity [2].

In the present research work, a series of CeO2-based oxides were synthesized and proposed

as possible catalysts for soot combustion. Binary and ternary mixed oxides with composition

Ce/Zr, and Ce/Zr/Y with different proportions were obtained via the citrate precursor

method. Prepared materials were characterized by X-Ray Diffraction (DRX), BET and

Infrared spectroscopy (FT-IR) and TPD techniques. Additionally the oxidation ability of

these materials for soot combustions was evaluated by thermogravimetric analyses (TGA).

[1] R. Prasad, V. Rao, A Review on Diesel Soot Emission, its Effect and Control, Bulletin of

Chemical Reaction Engineering & Catalysis, 5 [2] (2010) 69 – 86.

[2] Y. Wei and Z. Zhao, Preparation of ultrafine Ce-Based oxide nanoparticles and their

catalytic performances for diesel soot combustion, Journal of Rare Earths, 32 [2] (2014) 124-

130.




84

[ AMC-479 ] Ultrasonic Spray Pyrolysis Deposition of

BiFe1-xCrxO3 Thin Films

César Gustavo Mendoza Serrato ([email protected]) 1 , Alexis Esteban

López López 1 , José Ortiz Landeros 1 , Carlos Gómez Yáñez 1

1 Departamento de Ingeniería en Metalurgia y Materiales Escuela Superior de Ingeniería Química

e Industrias Extractivas, IPN, UPALM Av. Instituto Politécnico Nacional S/N CP 04510, México

D.F.

Multiferroic materials have a great potential to the design of electronic devices. The more interesting

features of a multiferroic material is the ability to shows parallel several properties such as

ferromagnetism, ferroelectricity, ferroelasticity etc.[1]

Recently, there are exhaustive research studies regarding the bismuth ferrite (BiFeO3), which is a

multiferroic material showing magnetic behavior. These interesting properties are able to be improved

through the structural and microstructural control of the material. An example of the aforesaid is the

material´s doping with different metal cations such as Cr, Ni and Co among others. [2]. Several

synthesis pathways have been reported to obtain both powders and thin films made of the pure phase

of bismuth ferrite such as sol-gel, sputtering, Pechinni and hydrothermal crystallization methods [3-

4].

The present work shows a systematic study regarding the fabrication of BiFeO3 thin films via Spray

Pyrolysis method. A series of homogeneous, crystalline and submicrometric

films of bismuth ferrite with general formula BiFe1-xCrxO3 were prepared with 0.02<x< 0.1 values.

The effect of different processing variables such as precursor concentration, temperature of

deposition, precursor concentration, flow rate of the carrier gas and spray to substrate length on the

film characteristics were studies by applying a Taguchi robust design. The obtained thin films were

characterized by DRX, SEM and AFM techniques among others.

Results suggest the potential of this simple and affordable spray pyrolysis technique to the fabrication

of good quality BiFeO3 thin films.

[1] Samar Layek, H. C. Verma, Magnetic and dielectric properties of multiferroic BiFeO3

nanoparticles synthesized by a novel citrate combustion method, Adv. Mat. Lett., 3 [6] (2012) 533-

538.

[2] Amit Kumar, K.L. Yadav,Magnetic, magnetocapacitance and dielectric properties of Cr doped

bismuth ferrite nanoceramics, Materials Science and Engineering: B, 176 [3] (2011) 227–230.

[3] D. Wang, M. Wang, F. Liu, Y. Cui, Q. Zhao, H. Sun, H. Jin, M. Cao, Sol–gel synthesis of Nd-

doped BiFeO3 multiferroic and its characterization, Ceramics International, 41 [7] (2015) 8768–

8772.

[4] Chao Chen, Hydrothermal synthesis of perovskite bismuth ferrite crystallites, Journal of Crystal

Growth, 291 [1] (2006) 135–139.




85

[ AMC-511 ] Studies on the thermal stability of

Ce0.85Sm0.15O2-Sm0.6Sr0.4Al0.3Fe0.7O3- carbonate

composites for possible use in the fabrication of ceramic-

carbonate dual phase membranes

Oscar Ovalle ([email protected]) 2 , José Ortiz-Landeros 1 ,

Heriberto Pfeiffer 3

1 ESIQIE, IPN 2 IIM, UNAM 3 IIM,UNAM

Emissions of greenhouse gases, mainly carbon dioxide (CO2), have increased excessively in recent

years mainly due to the burning of fossil fuels causing climate change. Some studies are oriented to

implement strategies to mitigate CO2 emissions to the atmosphere [1-2]. For example, a novel

mechanism that has been developed in recent years is based on the use of a dual phase ceramic-

carbonates membranes. These composite membranes have high CO2 selectivity and high temperature

stability. Briefly, the CO2 diffusion through the membranes involves the transportation of O2- ions

through the crystalline ceramic phase where the O2- ions react with the CO2 to form CO32- ions;

parallely, the CO32- ions will be transported through molten carbonates of the ceramic-carbonate

composite. The main issues to design this kind of membranes are the thermal stability and low ionic

conductivity of the ceramic phase. Actually, oxygen ionic conductivity is the limiting process for the

CO2 permability [3]. Based on the above, the aim of this work is to study the chemical and thermal

stability in CO2 atmosphere at high temperature as well as the ionic conductivity properties of the

Ce0.85Sm0.15O2-Sm0.6Sr0.4Al0.3Fe0.7O3-Carbonate composite. Recent studies involving this composite

have shown that it is a good ionic conductor at high temperatures making it an excellent candidate to

prepare dual phase membranes for high temperature CO2 permeation.

Composites materials were prepared via citrate precursor method and subsequently characterized

by XRD, SEM and Thermogravimetric (TGA) analyses. Thermal stability and sinterability of the

material in the temperature range of 700-1300 ºC was studied. Additionally, the prepared material

was subject to a long-term stability test under CO2 atmosphere. The obtained results suggest the high

potential of the proposed composite material to be used for the preparation of dual phase membranes.

[1] C. W. Jones et al. ChemSusChem (2009), 2, 796 – 854

[2] Pfeiffer, H., 2010. Advances on alkaline ceramics as possible CO captors. In: YunHang, H. (Ed.),

Advances in CO2 Conversion and Utilization. ACS Symposium Series, vol. 1056. American

Chemical Society, Washington DC, USA.

[3] J. Ortiz-Landeros et al. Chemical Engineering Science 104 (2013) 891–898




86

[ AMC-517 ] New Approach To The Synthesis of Lithium

Niobate Nanoparticles

Isis Maria Cota-Martínez 2 , Karina Patricia De La Torre Saenz 2 , Oswaldo

Sanchez-Dena 1 , José Trinidad Elizalde-Galindo 2 , Pierre Giovanni Mani-

Gonzalez 2 , Rurik Farías ([email protected]) 2

1 Instituto de Física, Universidad Nacional Autónoma de México, 04510, México, D. F.,

México 2 Universidad Autónoma de Ciudad Juárez, Av. Del Charro 450 Norte, Ciudad Juárez,

Chihuahua, 32310, México

A facile hybrid physical/chemical approach is reported to synthetizing lithium niobate

nanoparticles (LNNs). The approach involves mechanic activation of each precursor

(Lithium Carbonate and Niobium Oxide) until amorphization; followed by a chemical

dissolution in H2O at 90°C of amorphized precursors. The resulting solution was evaporated

obtaining a dry and amorphous powder that was annealed at 850°C for 2 h in room

atmosphere. The crystallization process from the amorphous state to the crystalline

LiNbO3 was followed by thermal analysis. The amorphus and annealed powders were

characterized by Raman spectroscopy, X-ray diffraction (XRD) and their morphology

examined by high-resolution transmission electron microscopy (HRTEM). XRD and Raman

confirmed that calcined powders are pure LiNbO3.




87

[ AMC-523 ] Optical and magnetic properties of

LiNbO3:Fe

Cesar D. Fierro Ruiz ([email protected]) 1 , Eva Maria Cabral

Larquier 1 , Jose Trinidad Elizalde Galindo 1 , Jose Rurik Farias Mancilla 1

1 Departamento de Física y Matemáticas, Universidad Autónoma de Ciudad Juárez, Av.

Charro 450 Nte. Col. Partido Romero CP 32310

Powders of LiNbO3:Fe were obtained by mechanosynthesis with different concentration of

Fe2O3. The process was realize in two steps. First, was mechano-active the Li2CO3 and Nb2O5

in high energy ball milling to obtain LiNbO3. Then the powder was calcined whit a ramp of

1.4 C per minute until 850 C, and it remained in isotherm for 2 hours. Second, mixed the

LiNbO3 obtained and Fe2O3 for 30 minutes in the high energy ball milling. Later, calcined

for 60 hours to 850 C for diffuse Fe atoms into the structure. The powders was

characterization for XRD, Raman spectroscopy, FT-IR spectroscopy and Vibration sample

magnetometer. Diffraction pattern show that LiNbO3 structure remains with the doped, also,

relative intensity of peaks related with [0 1 2] and [1 1 0] planes changes in function of doping

concentration. FT-IR spectrums did not show significant changes in the vibrational mode

related with Niobium and Oxygen octahedron. Raman spectrums present a change in the area

under curve corresponded to the regions between 210-295 cm-1 and 500-700 cm-1, this

vibrational modes are the lithium ions displacement and extension Nb-O, respectively.

Absorption edge, exhibit a change in function to the concentration of dopant. Powders had a

ferromagnetic behavior, and the magnetic moment net increases quadratically as a function

of doping concentration.




88

[ AMC-525 ] Synthesis and characterization of

polycaprolactone fibers with LiNbO3 nanoparticles

Eva Maria Cabral Larquier ([email protected]) 2 , Simon

Yobanny Reyes Lopez 1 , Cesar David Fierro Ruiz 2 , Jose Trinidad Elizalde

Galindo 2 , Pierre Giovanni Mani Gonzalez 2 , Jose Rurik Farias Mancilla 2

1 Departamento de Ciencias Químico Biológicas, Universidad Autónoma de Ciudad

Juárez, Av. Benjamin Franklin 4650 Zona PRONAF CP 32315 2 Departamento de Física y Matemáticas, Universidad Autónoma de Ciudad Juárez,

Av. Charro 450 Nte. Col. Partido Romero CP 32310

The electrospinning technique is one of the most technique used for fabrication of

nanofibers, these fibers are made from a conductor polymer, as polycaprolactone

(PCL). The LiNbO3 nanoparticles are mixed with PCL to achieve dispersion of

nanoparticles. Actually, there are no bibliography of fibers based on LiNbO3

nanoparticles embedded in PCL. For this reason we are developing a research, with a

possible applications in the development of waveguide. The nanofibers structure and

chemistry were characterized with x-ray diffraction (XRD), Raman and FT-IR

spectroscopies, and SEM.




89

[ AMC-561 ] Structural effects on sandy soils by adding

functionalized resins

Delia Cristina Altamirano-Juárez ([email protected]) 3 , Pedro

Montes-García 1 , Margarito Ortiz-Guzmán 1 , José Ernesto Domínguez-

Herrera 3 , Efraín Rubio-Rosas 2

1 Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional,

Unidad Oaxaca. Instituto Politécnico Nacional. Calle Hornos Núm. 1003. Col.

Nochebuena, Santa Cruz Xoxocotlán, Oaxaca, México. C. P. 71230 2 Centro Universitario de Vinculación y Transferencia de Tecnología; Prolongación

de la 24 Sur y Av. San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla,

Puebla, México. C. P. 72570 3 EP Nanotecnología, Universidad Tecnológica del Centro de Veracruz. Av.

Universidad Núm. 350, Localidad Dos Caminos, Cuitláhuac, Veracruz, México. C.

P. 94910

Novel composites were obtained from two types of soils with high silica content (>

60%) using as agglutinants different dosages of fatty acids and natural resins in both

low and high density. Both, the variations in the signal of X-Ray diffraction patterns

analyzed and changes observed by scanning electronic microscopy for the different

relationships of the agglutinants, reveal that it is possible to induce the formation of

compounds that it favors the mechanical resistance of adobe compacted blocks in

absence of cementing admixtures. The low cost of production and the environmental

benefit of not adding commercial cements allow recommending it as an appropriate

material for the residential construction industry, which fulfills the corresponding

standards.




90

BIOMATERIALS AND POLYMERS

(BIO)

Chairman:

Roberto Olayo (UAM-IZTAPALAPA)

Oral Session

[Invited-Talk] Development of Hybrid Biomaterials to Be

Implanted in Living Organisms to Fulfill Different

Functions

Rogelio Rodríguez

Centro de Física Aplicada y Tecnología Avanzada

Campus UNAM, Juriquilla

Biomaterials of different types were designed in our lab to be implanted to fulfill different

functions. Some of them were implanted for bone ingrowth in cases of traumatism; they

have the morphology of real bone. Others were designed as bio-package to protect sensor

devices that, once implanted, can provide valuable information of some conditions of the

host; this allows detecting, prematurely, some illness conditions to be treated from the early

stage, increasing the probability of success; in this case the morphology depends of the

implantation place. Finally, other biomaterials were designed for controlled drug release; in

this case the pore size should be small and the pore volume fraction as large as possible to

storage the large amount possible of medicament; this device was specifically designed as

biomarker to provide the position of the cancerous tumor and to release, in a controlled way

the medicament near the position of the tumor; the selected medicament was cis-platinum.




91

[ BIO-68 ] A composite made with a metakaolin based

geopolymer and rice husks in high proportions as an

alternative to concrete and wood

José de Jesús Pérez Bueno ([email protected]) 1 , Coraquetzali

Magdaleno Lopez 1

1 Centro de Investigación y Desarrollo Tecnológico en Electroquímica, S.C. Parque

Tecnológico Querétaro s/n Sanfandila, Pedro Escobedo, Qro., México. 76703.

The alkaline activation of aluminosilicates is a technology called geopolymerization, which

has no direct CO2 emissions. Geopolymers exhibit good physical porosity, at micro- and

nano-scale, low shrinkage, high mechanical strength, good thermal stability, durability,

surface hardness, chemical resistance and fire resistance.

In this work, a geopolymer composite is presented based on metakaolin as a matrix with

aggregates of agro-industrial waste in high ratio (with around 80-85% of rice husk – not

carbonized). The geopolymeric matrix covered the rice husks, which were found attached to

the matrix. The analysis of Confocal Laser Scanning Microscopy and SEM helped to identify

husks distribution within the matrix without being observed segregation or even distribution

of any component.

The materials obtained had values similar to those of the concrete resistance, which are

specifications searched in construction issues. Heat treating these materials become very

lightweight, without incorporate a lightweight aggregate or a chemical foaming agent. Their

strength properties did not change significantly when exposed to ambient or elevated

temperatures. The heat treatment given to these materials allowed obtaining a porous

structure and not soluble in water.

The high rates of rice husk in these materials, with compressive strengths similar to concrete,

particularly exceeded expectations and potentially become an alternative to concrete

providing an option to solve their disposal problem.




92

[ BIO-73 ] Preparation of polyallylamine as a drug

carrier for spinal cord lesions

Maribel González-Torres 1 , Maribel González-Torres 4 , Ma. Guadalupe

Olayo González ([email protected]) 2 , Guillermo J. Cruz

Cruz 2 , Lidia Ma. Gómez Jiménez 2 , Lidia Ma. Gómez Jiménez 4 , Francisco

González-Salgado 2 , Francisco González-Salgado 3 , Rodrigo Mondragón

Lozano 2

1 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Carr. México-

Toluca Km 36.5, Ocoyoacac, Edo. Mex., CP 52750, Mexico. 2 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Carr. México-

Toluca Km 36.5, Ocoyoacac, Edo. Mex., CP 52750, México. 3 Departamento de Posgrado, Instituto Tecnológico de Toluca, Av. Tecnológico s/n, Col. La

Virgen, Metepec, Edo. Mex., CP 52140, México. 4 Posgrado en Ciencia de Materiales, Facultad de Química, Universidad Autónoma del

Estado de México, Paseo Tollocan y Colón, Toluca, Edo. Mex., CP 52000, México.

Polyallylamine (PAl) synthesized by plasma was prepared as a drug carrier of dapsone to be

used as an implant in the spinal cord after a severe injury. PAl has been studied in the central

nervous system in areas with severe injuries to reduce secondary destruction of healthy tissue.

Dapsone on its part has been used subcutaneously with the same objective. In this work they

are prepared to be used together as implants directly in the lesion site. Once synthesized, PAl

films were lyophilized with water in order to induce porosity and to separate light fractions.

The dapsone uptake was done with different mass ratios: 1-1, 1-10, 1-100, by immersing the

polymer in dapsone and ethanol solutions with the result that the drug adheres to the polymer

forming non-homogeneous core shell structures. The release of dapsone from the polymer

was performed in two different solutions: water, and Krebs Ringer, two different models

were considered: dynamic and static simulating the similar conditions in the human fluids.

The desorption was measured by UV-Vis spectroscopy. Morphology and chemical structures

were studied before and after adding the drug.




93

[ BIO-75 ] Electromagnetic absorption and electric

interaction in hybrid structures of titanium oxide and

thiophene

Francisco González-Salgado 1 , Francisco González-Salgado 2 , Guillermo

J. Cruz Cruz ([email protected]) 1 , Ma. Guadalupe Olayo

González 1 , Genoveva García Rosales 2 , Maribel González-Torres 1 ,

Maribel González-Torres 4 , Lidia Ma. Gómez Jiménez 1 , Lidia Ma. Gómez

Jiménez 3




Estado de México, Paseo Tollocan y Colón, Toluca, Edo. Mex., CP 52000, México. 4 Posgrado en Ciencia de Materiales, Universidad Autónoma del Estado de México, Paseo

Tollocan y Colón, Toluca, Edo. Mex., CP 52000, México.

Organometallic hybrid structures of titanium oxide and thiophene (TiOx-Th) were

synthesized by plasma with the objective to design a photo-collector capable to absorb

electromagnetic energy in the visible solar irradiation interval. Titanium tetrapropoxide

(TTP) and thiophene (Th) were used as precursors with a 1:1 mass ratio, which chemically

reacted in a vacuum tubular glass chamber under rf resistive electrical glow discharges of

water vapor plasmas. Films and particles were formed with diameter in the 220-470 nm

interval, decreasing as the power of synthesis increased. The synthesized TiOx-Th

compounds absorbed electromagnetic radiation in two regions, 270-370 and 370-850 nm,

which could be related with the TiO and thiophene fractions respectively. The electrical

conductivity increased as a function of temperature as a volumetric effect sensitive to incident

beams on the surface. The activation energies of the electromagnetic absorption and the

transference of charges was calculated between 0.11 and 7.4 eV and compared. The presence

of particles on the surface is related with the absorption process and their capacity to transfer

electrical charges.




94

[ BIO-116 ] Particle size effect on thermal and

mechanical properties of PP filled with nano CaCO3

from eggshell.

Diana Samantha Villarreal Lucio ([email protected]) 1 ,

José Luis Rivera Armenta 1 , Ana Luara Martínez Hernández 2 , Ivan Alziri

Estrada Moreno 3 , Ulises Páramo García 1 , Ana María Mendoza Martínez 1

1 Departamento de Estudios de Posgrado e Investigación, Instituto Tecnológico de

Cd. Madero, Juventino Rosas S/N, Los Mangos, 89440 Cd Madero, Tamps., 2 Departamento de Estudios de Posgrado e Investigación, Instituto Tecnológico de

Querétaro, Av. Tecnologico S/N, Centro, 76000 Santiago De Queretaro, QRO 3 División de Ingeniería y Química de Materiales, Centro de Investigación de

Materiales Avanzados, Ave. Miguel de Cervantes 120, Industrial Chihuahua, 31109

Chihuahua, CHIH

Thermal and mechanical properties of a PP reinforced with three different particle

sizes of CaCO3 from eggshell were evaluated. Nanoparticles were obtained using two

mechanical attrition technics and an ultrasonic treatment: the eggshell was ground in

a blender, the second grinding was made in ball mill and finally the particles were

subjected to an ultrasonic treatment using three different sonication media. The

particle size diminished in every step, obtaining nanosized particles during the

ultrasonic treatment, using liquid media with different vapor pressures it is possible

to get distinct nano-sizes. Compounding was carried out in a mixer chamber. The

optimal PP-CaCO3 formulation according to particle size was investigated.

Thermogravimetric behavior, dynamic mechanical analysis and morphology of

resulted composites were analyzed.




95

[ BIO-129 ] Implantation of composite scaffold of pla-ha

coated with polypyrrole for the generation of bone

neotissue in rabbit: biological and mechanical evaluation.

María Guadalupe Flores Sánchez ([email protected]) 1 , Roberto

Olayo González 1 , Juan Morales Corona ([email protected]) 1 ,

Atlántida Raya Rivera 2 , Ricardo Esquiliano Rendón 2 , Raquel González

Pérez 2

1 Departamento de Física, Área de Polímeros, Universidad Autónoma Metropolitana,

Unidad Iztapalapa 2 Tissue Engineering Laboratory, Infantile Hospital of Mexico, Federico Gómez

Bone tumors such as osteosarcoma are the seventh leading cause of cancer death in Mexico.

Osteosarcoma originates in bone cells and occurs primarily in the metaphysis of long bones

like the distal femur, the proximal end of the tibia and humerus. Osteosarcoma affects people

between 2 and 60 years old and is more common in males.

Generally, a graft or bone substitute to help repair a skeletal deficiency due to this type of

disease is required. Tissue Engineering is an alternative to generate synthetic bone tissue,

using the combination of biomaterials, cells and biological factors, in order to give the patient

preservation in gait, functional recovery and mobilization.

Biomaterials that can be used as bone substitutes should possess biocompatibility,

biodegradability, and have to be osteoinductive, with proper mechanical properties. The

combination of polymers with ceramic materials meets most of the properties of bone. In this

work, the electrospinning technique was used to produce porous scaffolds of poly(lactic acid)

(PLA) and hydroxyapatite (HA), which serve as support for the growth of bone cells,

osteocytes. To induce cell adhesion and stimulation, a thin film of polypyrrole (PPy-I) doped

with iodine is deposited by plasma polymerization on the scaffolds. The scaffold made of

PLA-HA-PPy/I underwent in vivo cell culture in rabbits for 30 days. The newly formed tissue

was characterized by scanning electron microscopy, histology studies and mechanical stress

tests.




96

[ BIO-147 ] Plasma polimeized semiconductor polymers

as cell growth materials

Roberto Olayo ([email protected]) 1 , Nancy Cecilia Islas-Arteaga 3 ,

Juan Morales-Corona 1 , Odín Ramírez-Fernández 3 , Rafael Godinez-

Fernández 2


Unidad Iztapalapa. 2 Departamento de Ingeniería Eléctrica, Lab. de Ingeniería de Tejidos, Universidad

Autónoma Metropolitana, Unidad Iztapalapa. 3 Posgrado en Ingeniería Biomedica, Universidad Autónoma Metropolitana, Unidad

Iztapalapa.

Polymers such as polyaniline, PAn, polypyrrole, PPy, the polyallylamine, PAlly, and

polythiophene, PTh, may have semiconductor properties when are plasma polymerized and

on the surface have functional groups as amines or sulfurs of the thiophene ring. This makes

them suitable for testing in cell culture. Glass substrates coated with the four materials, PAn,

PPy, PAlly, and PTh, were prepared Through the plasma polymerization technique, at powers

of 15W, 30W and 50W and polymerization times of 15 min and 30 min. These materials

were characterized by contact angle, SEM, FT-IR-ATR and Raman spectroscopy. Human

hepatocyte cells, HepG2, were cultured on the substrates, with approximately 1x106 cells per

material. The cell culture was followed for 11 days and photomicrographs of each sample

were taken. The evolution of cell growth was followed in all materials (anchorage,

reproduction and monolayer formation).




97

[ BIO-284 ] Surface characterization of titanium surfaces

before and after exposition to an hydrogen peroxide

ambient

Abril Fonseca García ([email protected]) 3 , Abril Fonseca

García 4 , Jonatan Peréz Alvaréz 3 , Mauro Giorcelli 1 , Argelia Almaguer

Flores 2 , Sandra Elizabeth Rodil Posada ([email protected]) 3

1 Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi

24, Torino 10129, Italy. 2 División de estudios de posgrado e investigación, Facultad de Odontología, Universidad Nacional

Autónoma de México, Circuito exterior s/n, Ciudad Universitaria, 04510 México D. F. Mexico. 3 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito

Exterior s/n, CU, México D.F. 04510, Mexico 4 Posgrado en Ciencia e Ingeniería de Materiales, Universidad Nacional Autónoma de México.

The most important property of materials used for fabricating implants is the biocompatibility,

followed by corrosion resistance. In implantology and orthopedics, the metal more used is titanium

(Ti) due to its excellent osseointegration properties which lead to a successful recovery and

improvement in quality of life of patients. Nevertheless, from the fundamental point of view, it is not

clear why Ti is the most suitable metal for biomedical applications.

In this work, we studied the behavior of Ti surfaces in inflammatory environmental. For this aim, we

created an environment rich of oxidizing species that simulate a body inflammatory response after

the implantation of a foreign body. The response of the Ti surfaces is compared to medical grade

stainless steel (AISI316L) and titanium oxide thin films deposited on Ti substrates. The films were

deposited by magnetron sputtering using a pure Ti target and an argon-oxygen environment. The three

materials; Ti, AISI316 and TiOx films, were immersed in a physiological solution (Hartman) with

the addition of 50 mM of hydrogen peroxide to simulate the foreign body reaction environment. The

surfaces were kept in immersion for 7 days, refreshing solution every 24 hours in order to keep the

hydrogen peroxide in reactive conditions. The surfaces were characterized before and after 7 days of

immersion by X ray diffraction, atomic force microscopy to study roughness and topography, X-ray

photoelectron spectroscopy for studying the chemical composition, contact angle to evaluate the

surface energy and finally, potentiometric titration to obtain the surface charge.

Acknowledgements: To CONACyT for the PhD scholarship and economical support to both and

PAPIIT-UNAM IN118814, IN118914, IG100113 grants.




98

[ BIO-454 ] Effects of cooling rate, morphological and

structural propierties of BIO-HAP from bovine bone

Cristian Felipe Ramirez Gutierrez 1 , Anderzon Felipe Palechor Ocampo 1 ,

Sandra Milena Londoño Restrepo 1 , Beatriz Millan Malo 1 , Mario Enrique

Rodriguez Garcia ([email protected]) 1

1 Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de

Mexico Campus Juriquilla, Qro., Mexico

Hydroxyapatite (HAp) is a ceramic material with chemical formula: Ca10(PO4)6OH2. Hap is

the major mineral component of the vertebrate bone and tooth. Other mineral phases present

in the bone are calcium phosphate, dicalcium phosphate, tricalcium phosphate, and others.

Further, Hap contains mineral traces, such as, Na, Mn, K, Li, Cr, Mg, Fe, and others, that are

important in the bio-mineralization process. The effect of cooling rate after calcined on

physicochemical properties of biohydroxyapatite (Bio-Hap) from bovine bone was studied

in this investigation. Calcination process was carried out in furnace in air atmosphere to 900

°C at 5 °C/min. The samples studies were: HAP-CW (Hap cooled in water at room

temperature), Hap-Fair (Hap cooled into the furnace), Hap-CAir (Hap cooled out furnace),

and Hap-N2 (Hap cooled in liquid nitrogen). The samples were characterized thermally by

thermogravimetrical analysis (TGA), morphologically by scanning electron microscopy

(SEM), and structurally by X-ray diffraction (XRD). The results indicate that low cooling

rate for Hap cooled into the furnace produce single crystals with high crystalline quality.

Keywords: Bio-hydroxyapatite, cooling rates, crystalline quality.

1. Giraldo-Betancur AL, Espinoza-Arbelaez DG, del Real-Lopez A, Millan-Malo BM,

Rivera-Muñoz E, Gutiérrez-Cortez E, Pineda-Gomez P, Jimenez-Sandoval SJ,

Rodriguez-Garcia ME. Comparison of physicochemical properties of bio and

commercial hydroxyapatite. Curr Appl Phys 2013; 13:1383–1390.

2. Krishna SR, Chaitanya CK, Seshadri SK, Kumar TSS. Fluorinated hydroxyapatite by

hydrolysis under microwave irradiation. Trends Bio-matter Artif Organs 2002;

16:15–17.

3. Bahrololoom ME, Javidi M, Javadpour S, Ma J. Characterization of natural

hydroxyapatite extracted from bovine cortical bone ash. J Ceram Process Res 2009;

10:129–138.




99

[ BIO-502 ] Growth of silver particles with different

morphology on hydroxyapatite

Yosemik Arjuna León Nataret 2 , Aarón Israel Díaz cano 2 , Efraín Rubio

Rosas 1 , Edith Bravo González ([email protected]) 2

1 Benemérita Universidad Autónoma de Puebla, San Manuel, 72570, México 2 Instituto Politécnico Nacional, UPIITA, Gustavo A. Madero, 07340, México

The synthetic hydroxyapatite (HA) has a similar mineral phase with the bone and with

excellent characteristics of biocompatibility and osseointegration in a biological medium.

Although exist problems in connection with bacterial infections when these implants are

inserted into the human body; One antibacterial agent proposed is the silver and his alloys,

these has been studied extensively, showing that had antibacterial effects through interaction

of proteins and enzymes of the bacteria causing structural damage in to the cell wall and in

the membrane, the investigations show that at low concentrations of silver is not toxic to

mammals, but in high concentrations cans cause argyria and cytotoxicity.

In this paper was determined the influence of the growth of silver nanostructures on the

surface of structures of bovine hydroxyapatite with different morphology. The silver particles

were obtained by chemical reduction, taking as precursors Silver Nitrate (AgNO3), Sodium

Citrate (Na3C6H5O7) and ammonium hydroxide (NH4OH). The characterization was

performed by scanning electron microscope (SEM), X-ray diffraction (XRD) and Atomic

Force Microscope (AFM). The results showed that the bone lamellae are an important factor

on the growth and morphology of silver nanoparticles, even when the chemical composition

of the substrate is the same.

One sample observed by scanning electron microscope showed the growth of nanostructures

on the surface of the bone lamellae, also shows that in the surface of this bone has smaller

structures with low dimensions in nanometric scale. When it used high concentrations, the

silver particles grow up into lamellae boundaries as nucleation centers.




100

[ BIO-539 ] Osteogenic Differentiation of Human

Mesenchymal Stem Cells by Porous Bovine Bone Matrix

Nayeli Rodríguez Fuentes ([email protected]) 2 , Luz E Alcántara

Quintana 1 , Javier R Ambrosio Hernández 3 , Cristina Piña Barba 2

1 Aplicaciones en Terapia Celular, S. A. de C. V., Santa Barbara. Col. Jardines de Santa

Rosa. Puebla, México 2 Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en

Materiales, Universidad Nacional Autónoma de México. Mexico City 04510, Mexico 3 Departamento de Microbiología y Parasitología, Facultad de Medicina-UNAM, Mexico

City 04510, Mexico

The differentiation of mesenchymal stem cells (MSCs) in vitro, is a processes that depends

on the culture conditions. Soluble compounds such as grow factors and numerous reagents,

result in a chondrogenic, adipogenic, neurogenic or osteogenic differentiation. Osteogenic

differentiation of MSCs in vitro is induced by the presence of dexamethasone, ascorbic acid

and β-glycerol phosphate, however, the role of the insoluble compounds such as the

biomaterials in regulating the osteogenic differentiation of MSCs are unclear.

In this study we delineate the role of the porous bovine bone matrix (NKB) in the osteogenic

induction of MSCs in an in vitro model, through the measurement of expression of the gene

key markers in the osteogenic differentiation such as transcriptional factor CBFA-1 and

Osteocalcin.

The results shown that NKB has osteoinductive properties in MSCs cultures, because induce

the activation of CBFA-1 and Osteocalcin, without the addition of the soluble inductors. In

addition, the NKB promote cell adhesion and proliferation similarly to the positive control,

which is a culture of MSCs without NKB but with osteoblastic inductors as ascorbic acid, B-

glycerophosphate and dexamethasone. This osteoinductive property of NKB, as well as its

full characterization might favour its best use in regenerative medicine.

Acknowledgements. The authors acknowledges to DGAPA/UNAM for financial support

received as a postdoctoral grant and would like to thank the PAPIIT program for the financial

support through the IG100114 project, CONACyT through project 214128. Also to thank the

DGAPA IN201510 and DGAPA IXTLI IX200610.




101

[ BIO-554 ] CHEMICAL DERIVATIZATION OF

PLASMA POLYMER FILMS FOR

QUANTIFICATION OF AMINE, HYDROXYL AND

CARBOXYL GROUPS BY HR-XPS

Juan-Carlos Ruiz-Bucio ([email protected]) 1

1 División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana

Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 Mexico City, Mexico

Plasma-assisted modification- and deposition-processes have been used for creating

bioactive polymer surfaces in biomedical and cell-culture applications. Plasma-polymerized

Allylamine (pp-AA) or Nitrogen (N)-rich organic thin-deposits are particularly advantageous

because N-containing functional groups, specifically primary amines (-NH2), can readily be

incorporated [1, 2]. Oxygen-rich plasma films obtained with different precursors, e.g. gas

mixtures of oxygen-ethylene or acrylic acid and allylalcohol monomers, are of interest as a

biomaterial as well [3]. It is not possible to quantify –NHx and –OH groups in a polymer

containing both functionalities when chemical derivatization (CD) with survey-XPS or high

resolution X-ray photoelectron spectroscopy (HR-XPS) are performed, but together with CD

reactions and HR-XPS. The use of CD and HR-XPS for labeling of the desire functional

groups is a powerful tool for quantification of -NHx, -OH and COOH groups, among others

[3,4].

The present work describes the use of different derivatization reactions for quantification of

-NHx, -OH and COOH groups present in different plasma polymer films deposited by a

PECVD method. XPS spectra, before and after derivatization, will be present for discussing

their chemical characterization.

References:

1. R. Förch, A. N. Chifen, A. Bousquet, H. L. Khor, M. Jungblut, L.-Q. Chu, Z. Zhang, I.

Osey-Mensah, E.-K. Sinner, W. Knoll (2007); Chem. Vap. Deposit. 13, 280.

2. J. C. Ruiz, A. St-Georges-Robillard, C. Thérésy, S. Lerouge, M. R. Wertheimer (2010);

Plasma Process. Polym. 7, 737.

3. J.-C. Ruiz, P.-L. Girard-Lauriault, M. R. Wertheimer (2015); Plasma Process. Polym. 12,

225.

4. J.-C. Ruiz, S. Taheri, A. Michelmore, D. E. Robinson, R. D. Short, K. Vasilev, R. Förch

(2014); Plasma Process. Polym. 11, 888.




102

[ BIO-559 ] Analysis of the biocidal efficacy of Neem oil

embedded in nanostructured reservoirs of Titanium

Oxide

Héctor de Jesús Andrade-Tomas ([email protected]) 2 , Delia

Cristina Altamirano-Juárez ([email protected]) 2 , Octavio

Maldonado-Saavedra 2 , Efraín Rubio Rosas 1 , Juan Manuel Padilla-Flores

2

1 Centro Universitario de Vinculación y Transferencia de Tecnología; Prolongación de la

24 Sur y Av. San Claudio, Ciudad Universitaria, Col. San Manuel, Puebla, Puebla, México.

C. P. 72570 2 PE Nanotecnología, Universidad Tecnológica del Centro de Veracruz. Av. Universidad

Núm 350; Localidad Dos Caminos. Cuitláhuac, Veracruz, México. C. P. 94910

In recent years there has been increased the interest in the use of natural extracts as an

alternative to the control of microorganisms pathogenic in humans. Neem oil has become

important because its active ingredient Azadirachta indica is associated with beneficial

effects against infectious diseases. Microparticles of Neem oil were impregnated following

a hydrothermal route, over wafers of Titania elaborated from powders previously synthesized

by the Sol-Gel Technique.

The concentration and degree of diffusion of Neem oil on the surface of the tablets were

evaluated using optical and scanning microscopies; two lots of impregnated tablets were

randomly selected to develop bacterial cultures of Escherichia Coli both in the surface as

immersed in the composite powder of Neem/TiO2. It was observed that the effectiveness of

Neem oil was greatest with powdered samples, therefore it is proposed that the intensity of

the bactericidal reactivity of Neem oil microparticles is influenced by the increase surface

porosity of Titanium Oxide.




103

Sesión Poster

[ BIO-6 ] Surface roughness and hardness evaluation of

some base metal alloys and denture base acrylics used for

oral rehabilitation

Gabriela Cortés Sandoval ([email protected]) 2 , Juan Pablo Loyola

Rodríguez 4 , Rita Elizabeth Martínez Martínez 4 , Pánfilo Raymundo

Martínez Rodríguez 3 , Vladimir Alonso Escobar Barrios 1

1 División de Materiales Avanzados, Instituto Potosino de Investigación Científica y

Tecnológica, A.C., Camino a la Presa San José # 2055, Lomas 4a. sección, CP 78210, San

Luis Potosí, SLP, México 2 Doctorado Institucional en Ingeniería y Ciencia de Materiales, Universidad Autónoma de

San Luis Potosí, Av. Dr. Manuel Nava # 6, Zona Universitaria, CP 78290 San Luis Potosi,

SLP, México 3 Instituto Tecnológico Superior de Irapuato, carretera Irapuato-Silao km 12.5, Irapuato,

Guanajuato, México 4 Master Degree in Advanced Education in General Dentistry, San Luis Potosi University,

Av. Dr. Manuel Nava # 2, Zona Universitaria, CP 78290 San Luis Potosi, SLP, México

Dental materials for clinical use are considered medical devices that have to meet stringent

safety and efficacy requirements. The aim of this study was to evaluate and compare, basal

and after polishing, surface roughness, topography, and hardness of some dentures base

materials and base metal alloys used in oral rehabilitation by using atomic force microscopy

(AFM), scanning electron microscopy (SEM), and Vickers hardness test (VHN),

respectively. For each study group, 10 cylindrical specimens measuring 3 mm in diameter

and 20 mm thick were prepared following the manufacturer's instructions. All specimens

were subjected to basal measurements for subsequent comparisons and then samples

were polished by the standard polishing procedure for each material used. To determine the

difference between the variables before and after polishing, the Student t test (dependent

samples) was used. The comparison between the study groups was performed using ANOVA

one-way and Tukey–Kramer test. Significant differences between basal roughness values and

after a polishing process were observed. Mainly there appears to be a relationship between

the content of the material that confers the hardness and the surface roughness values. The

SEM analysis showed significant changes in surface topography of base metal alloys.

Thermosetting acrylic presented the lowest roughness value before (93 nm) and after (48

nm) polishing technique, and apparently did not show any visual surface topography change.




104

[ BIO-10 ] Comparison of physical and mechanical

properties of three base metal alloys used in restorative

dentistry.

Gabriela Cortés Sandoval ([email protected]) 2 , Juan Pablo Loyola

Rodríguez 3 , Rita Elizabeth Martínez Martínez 3 , Vladimir Alonso Escobar

Barrios 1

1 División de Materiales Avanzados, Instituto Potosino de Investigación Científica y

Tecnológica, A.C., Camino a la Presa San José # 2055, Lomas 4a. sección, CP 78210, San

Luis Potosí, SLP, México 2 Doctorado Institucional en Ingeniería y Ciencia de Materiales, Universidad Autónoma de

San Luis Potosí, Av. Dr. Manuel Nava # 6, Zona Universitaria, CP 78290 San Luis Potosi,

SLP, México 3 Master Degree in Advanced Education in General Dentistry, San Luis Potosi University,

Av. Dr. Manuel Nava # 2, Zona Universitaria, CP 78290, San Luis Potosi, SLP, México

The purpose of the present study was to evaluate and compare some physical and mechanical

properties of three base metal alloys commonly used in oral rehabilitation: cobalt-chromium

(R-800®), nickel-chromium (Verabond®) and copper-aluminum (NPG®). Tests were

performed in accordance with the ADA specification no. 14 for dental base casting alloys.

Thirty specimens of 40 mm in length and 3 mm diameter were prepared according to the

manufacturer’s instructions. The following characteristics were analyzed: flexural strength,

flexural modulus, fracture toughness, surface hardness and surface roughness. The

mechanical properties were performed using a three-point bending test on a universal testing

machine. The span distance between two supports was 32 mm and the crosshead speed during

the test was 20 mm/min. Vickers harness test was performed using a microhardness tester

with an applied load of 9.8N at 10 seconds dwell time; three Vickers indentations were

conducted for each specimen and standard deviation was recorded. All roughness

measurements were obtained by atomic force microscopy in contact mode calibrated to 49.5

mm2 sample surface; three measurements were performed for each specimen and the average

for Ra values was used for the statistical analysis. The mean and standard deviation are

reported. After analyzing the obtained results important features were observed. The alloys

containing copper-aluminum exhibited the lower mechanical properties compared to alloys

containing chromium. In the case of physical properties, it appears to be a relationship

between the content of material that confers the hardness and the surface roughness values.




105

[ BIO-23 ] multiscale polymer composites for aircraft

industry, based on functionalized carbon nanotubes:

processing and characterization

Juan Manuel Hernandez Andrade 1,2 , Carlos Rubio Gonzalez 1 , Carlos

Velasco Santos ([email protected]) 2

1 Centro de Ingeniería y Desarrollo Industrial (CIDESI), Av. Playa Pie de la Cuesta No.

702. Desarrollo San Pablo, C.P. 76130, Santiago de Querétaro, Querétaro, México. 2 División de Estudios de Posgrado e Investigación, Maestría en Ingeniería, Instituto

Tecnológico de Querétaro, Av. Tecnológico s/n esq. Gral. Mariano Escobedo, Col. Centro

Histórico, C.P. 76000, Santiago de Querétaro, Querétaro, México.

The use of carbon fiber- reinforced polymers (CFRP) in the aircrafts and automobile industry

is well known, these materials possess excellent mechanical properties of high strength and

stiffness, in addition to low density in comparison to the metals which lightens the final

weight. However, the weakness of these materials is related with the zones where the resin

prevails over carbon fiber and the fracture can be propagated there. On the other hand, in the

last decade, carbon nanotubes (CNTs) have shown be excellent reinforcement to polymer

matrices to develop polymer nanocomposites. Thus, it has been proposed recently, the

combination of carbon fiber (micro level) and nanomaterials to processing multiscale

composites in order to take advantage of both levels (micro and nano). Therefore, in this

research are processed laminated CFRP, these are modified with CNTs to improve the

mechanical properties of the final component. Functionalization of CNTs achieved in a

microwave generates chemical groups that are useful in the dispersion of the polymer matrix

and then in the properties of multiscale composites. Functionalized and unfunctionalized

CNTs were dispersed using an epoxy resin between prepreg plies of CFRP and cured in

autoclave. Different concentrations (0.1 wt%, 0.3 wt%, and 0.5 wt%) of CNTs were added

in epoxy resin matrix. The composite materials were characterized by Dynamical Mechanical

Analysis (DMA), tension, flexion and compression tests to evaluate thermal and mechanical

properties. The resin employed to disperse nanomaterials presents lower thermal properties

and softens the composites. However, it is observed that resin improves dispersion of

nanomaterials. Also, the functionalization is useful to improve the mechanical properties in

some concentrations. Hence, multiscale polymer composites using functionalized nanotubes

could be contributing to diminish the low-impact fracture and improve the thermo-

mechanical properties when a correct resin is used to disperse nanomaterials.




106

[ BIO-74 ] Using plasma to improve adhesion of

polyallylamine coatings on metallic implants for the

circulatory system

Lidia Ma. Gómez Jiménez 1 , Lidia Ma. Gómez Jiménez 3 , Guillermo J. Cruz

Cruz ([email protected]) 1 , Ma. Guadalupe Olayo González 1 ,

Maribel González-Torres 1 , Maribel González-Torres 3 , Francisco

González-Salgado 1 , Francisco González-Salgado 2 , Rodrigo Mondragón

Lozano 1




Estado de México, Paseo Tollocan y Colón, Toluca, Edo. Mex., CP 52000, México.

One major causes of death in the population is the decrease of blood flow in the circulatory

system caused by blockage of veins and arteries. An alternative to solve this problem is the

implantation of a metallic mesh in the obstructed section to enlarge the diameter of the

obstructed duct to partially restore the blood circulation. However, most metallic surfaces

cause rejection reactions of different magnitude in the circulatory system which generate

clots and obstructions again. Trying to avoid the post-implant reobstruction, the metallic

devices have been coated with compatible biomaterials strong enough to resist the forces of

the blood flow.

In this area, this work presents a study of polyallylamine (PAl) coatings synthesized by

plasma on nitinol and stainless steel substrates capable to resist the blood flow forces in

Phosphate-Buffered Saline solutions (PBS) similar to the blood. Erosion, oxidation and

sensitization with Argon and hydrogen peroxide plasmas were used on the metallic surfaces

before and during the synthesis of the polymers. To simulate the conditions of the blood

pumping and the heart's chamber contractions, the coatings were placed in tubes at a solution

rate of approximately 66.5 cm/s at 37°C. The results showed that the coatings resisted up to

two months without apparent degradation. SEM, XPS and contact angle analyses were used

to follow the process.




107

[ BIO-80 ] Structural Characterization of Protein

Microsensors Array by Mean of Optical Profilometry

and AFM

Claudia Mendoza-Barrera 1 , Victor Altuzar ([email protected]) 1 ,

Miguel A. Meléndez-Lira 2 , Julio C. Tinoco-Magaña 1 , Severino Muñoz-

Aguirre 3

1 Centro de Investigación en Micro y Nanotecnología, Universidad Veracruzana 2 Departamento de Física, CINVESTAV-IPN

3 Facultad de Ciencias Físico-Matemáticas, BUAP

A microarray is a matrix containing from hundreds to thousands of microscopic sensory

elements or spots printed on a flat functionalized surface which allows a specific interaction

of multiple biomolecules including proteins. Some examples of reading this technology

include the surface plasmon resonance and variable wavelength scanners used to determine

the superficial density of biomolecules interacting with the microsensors. Nevertheless, none

of these techniques provides the information relative to the structure of the interaction of the

microsites fabricated for the biosensing. As a result, in this work we propose the combined

use of the Atomic Force Microscopy (AFM) and optical profilometry to determine the

structure and density of the interaction of microsite lines of bovine serum albumin (0.1, 0.5,

0.75 and 1.0 mg/ml) fabricated on the previously functionalized gold/glass substrate. For

this purpose, we utilized solutions of bovine serum albumin (1.0 mg/ml) as the analytes

during the protein-protein interaction. The negative control microsites corresponded to a line

of white solutions of fibrinogen of human serum (1.0 mg/ml) which proved that the surface

density (molecules/area) of the not-washed BSA spots is correlated to their thicknesses: 957.9

nm (1.0 mg/ml), 636.6 nm (0.75 mg/ml), 639.7 nm (0.5 mg/ml), and 490.4 nm (0.1 nm),

whereas after the interaction with anti-BSA (1.0 mg/ml) they corresponded to 508.6, 218.0,

170.7, and 130.8 nm, respectively. In this way we proved that, before and after the protein

interaction, the average spot roughness decreased with the concentration of the protein used

for the fabrication of microsensors.




108

[ BIO-86 ] Synthesis and toxicity of Europium-doped

nanohydroxyapatite for biomedical applications

Paulina Guadalupe Miranda Meléndez ([email protected]) 1 ,

Gabriel Alejandro Martínez Castañón 2 , Nuria Patiño Marín 2 , Nereyda

Niño Martínez 1 , Norma Verónica Zavala Alonso 2 , Facundo Ruiz 1

1 Doctorado Institucional en Ingeniería y Ciencia de Materiales 2 Doctorado en Ciencias Odontológicas

In this study europium- doped nanohydroxyapatite was synthetized using a simple aqueous

precipitation method. Calcium nitrate tetrahydrate, Ammonium dihiydrogenphosphate and

Europium nitrate, were used, respectively, as Ca, P and Eu precursors with a Ca:P ratio 1.67.

The nanohydroxyapatite was doped with 3, 5, 10 and 20 wt% of europium. Powders obtained

were studied after they were dried at 70°C and hydrothermal treated at 120°c by 2 hours. The

samples were analyzed by (Transmission Electron Microscopy) TEM, (X-ray diffraction)

XRD, (Fourier transform infrared spectroscopy) and FT-IR, (Photoluminiscence) PL. The Eu

concentration toxicity effects of nano Eu:HAP were studied on human fibroblasts cells in

vitro.

The sizes of the crystallites were about 10-70 nm with irregular morphology and present the

(P63/m space group) phase corresponding to the JCPDS card 9-0432.The Eu-doped samples

present photoluminescence lines at 590, 615, and 699 nm. The results of the toxicity

experiments indicated that the powders were biocompatible and would not cause toxic

reactions. This work provides an interesting view of the role of nanohydroxyapatite as ideal

biomedical materials in future biomedical applications.

Keywords: nanohydroxyapatite, synthesis, toxicity.

References:

Carmen Steluta Ciobanu, S. L. (2012). Synthesis, Structure, and Luminescent Properties of

Europium- Doped Hydroxyapatite Nanocrystalline Powders. Journal of Nanomaterials, 1-9.

Sangeeta Dey, Mitus Das, Vamsi Krishna Balla (2014). Effect of hydroxyapatite particle size,

morphology and crystallinity on proliferation of colon cancer HCT116 cells. Materials

Science and Engineering C336-339

Presenting author’s email: [email protected]




109

[ BIO-101 ] Determination of Lead Ions Removed from a

Flowing Electrolyte in Presence of a Magnetic Field

Using Raman Spectroscopy

Rogelio Rodriguez Talavera ([email protected]) 1 , Maykel González

Torres 1 , Susana Vargas Muñoz 1 , Blanca Huerta 2 , Guadalupe Méndez 2

1 Centro de Física Aplicada y Tecnología Avanzada. Universidad Nacional Autónoma de

México. 2 Centro de Investigación en Química Aplicada

Purpose: The removal of lead ions in a flowing electrolyte is a difficult problem, mainly

because the ions distribute homogeneously in the fluid due to their mutual electrical

repulsion. In this work is reported a new and non-invasive method to remove efficiently metal

ions in aqueous solution flowing in a tubing, using a magnetic field to deflect the ions

trajectories and concentrate these in one side of a specially designed cell; once the ions are

concentrated, they can be removed. This technique could be used to remove toxic ions in the

interior of arteries and veins in patients intoxicated by the ingestion of these metal ions.

Method: Raman spectroscopy was used to prompt determination of removed metal ions. The

presence of a magnetic field in an aqueous electrolyte flowing in a rectangular cell, allows

an increment in the ions concentration due to the deflection effect of the ions trajectory.

Results: It is possible to increase, in a region of the cell, the ions concentration in more than

80% respect to the average concentration; the removed ions are taken from this region. This

is a rapid, efficient and non-invasive method for the removal of ions in aqueous solution.

Raman spectroscopy was found to be a suitable technique to determine the amount of

removed ions.

Conclusion: The results indicated that it is possible to increase the ions concentration more

than 80% in a region where it is possible to remove them. The increment in ions concentration

produced by the deflection due to the magnetic field, together with the use of Raman

spectroscopy, allows a rapid analysis of the removed ions without any previous preparation,

suggesting that is a useful method for metal ions separation of interest to medical physicists.




110

[ BIO-103 ] Surface modification of poly (3-

hydroxybutyrate-co-3-hydroxyvalerate) by direct

plasma- radiation-induced graft polymerization of

hydroxyethyl-acrylamide

Maykel González Torres 2 , Rogelio Rodríguez Talavera 2 , Susana Vargas

Muñoz 2 , Alicia del Real López 2 , Gabriel López Calzada 2 , Efrain Rubio

Rosas 1 , Eric Reyes Cervantes 1

1 Benemérita Universidad Autónoma de Puebla, Prolongación de la 24 Sur y Ave San

Claudio. Ciudad Universitaria, Col San Manuel, C.P 72570, Puebla, Pue, México. 2 Centro de Física Aplicada y Tecnología Avanzada. Universidad Nacional Autónoma de

México. Campus Juriquilla, Boulevard Juriquilla 3001, Santiago de Querétaro, Querétaro,

C.P 76230, México

A new type of cell-carrier-scaffold based on the surface modification of poly(3-

hydroxybutyrate-co-3-hydroxyvalerate) by direct plasma- radiation-induced graft

polymerization of N-hydroxyethyl-acrylamide was prepared. Parameters as: membrane

position for plasma treatment, delivering power and exposure time were varied. The yields

over the films surface, the chemical changes, the morphology and roughness, were surveyed.

The results indicate that the tailoring is more favourable at 10 W for 10 minutes because at

lower values, low degrees of grafting are obtained, and at higher values, there is an increment

of the film degradation. It was found that the use of 30% v/v of HEAA/ethanol (etching

agent) leads to the formation of a coral like structure with greater average roughness than the

pristine biomaterial. The modified surface slightly increased their hydrophilicity. .




111

[ BIO-127 ] Effects in clinical chemistry and hematology

of rats exposed to silver nanoparticles using

intraperitoneal administration

Diana Peralta Álvarez ([email protected]) 5 , León Francisco

Espinosa Cristóbal ([email protected]) 2 , Gabriel Alejandro

Martínez Castañón 4 , Maribel Cervantes Flores 3 , Alejandro Donohue

Cornejo 1

1 Departamento de Estomatología, Instituto de Ciencias Biomédicas, Universidad

Autónoma de Ciudad Juárez 2 Departamento de Estomatología, Instituto de Ciencias Biomédicas, Universidad

Autónoma de Ciudad Juárez. 3 Facultad de Ciencias Químicas, Universidad Juárez del Estado de Durango.

4 Laboratorio de Nanobiomateriales, Facultad de Estomatología, Universidad Autónoma

de San Luis Potosí 5 Maestría en Ciencias Estomatológicas, Facultad de Odontología, Universidad Juárez del

Estado de Durango.

The bacterial effect of silver nanoparticles (SNP) has allowed their application in several

areas, including the biomedical field; very few studies in the nowadays has evaluated the

toxic effect of this nanomaterials using intraperitoneal way in vivo. This study evaluated

clinical chemistry and hematology test in Wistar rats exposed al SNP by intraperitoneal way.

Were prepared and characterized two sizes of SNP using dynamic light scattering (DLS) and

transmission electron microscopy (TEM). Three concentrations of SNP were administrated

intraperitoneal way (133.75µg/ml, 535µg/ml, 1070µg/ml) in periods of 96 hours to females

Wistar rats for 30 days. Blood samples were collected before of SNP administration (0 days),

in the middle of study (15 days) and in the end of exposition (30 days) for clinical chemistry

and hematology evaluation.

The size, distribution end shape of SNP (7.1 nm and 17.5 nm) was evaluated by DLS and

TEM. The clinical chemistry values showed differences in urea nitrogen, uric acid, creatinine

and triglycerides in the different sizes of SNP; in hematology monocytes and neutrophils

values were found increased in both sizes of SNP used.

The alterations found suggest a toxic effect of SNP administrated intraperitoneal way at

Wistar rats causing kidney functions and inflammatory responses which can be related with

size, shape, concentration and administration way used.




112

[ BIO-128 ] Biocompatible scaffolds based in

polyhydroxybutyrate for tissue engineering applications.

Emma Cortés Ortiz 2 , Maykel González Torres 1 , Susana Vargas Muñoz 1 ,

Roberto Olayo-Valles 2 , Juan Morales-Corona ([email protected]) 2 ,

Rogelio Rodriguez Talavera 1 , Roberto Olayo 2

1 Centro de Física Aplicada y Tecnología Avanzada. Universidad Nacional

Autónoma de México. Campus Juriquilla 2 Departamento de Física, Área de Polímeros, Universidad Autónoma

Metropolitana, Unidad Iztapalapa

An ideal scaffold for tissue engineering must allow for three-dimensional cell culture,

have high porosity, and must be biocompatible and biodegradable. The decomposition

products should not be toxic to the host, should act as a temporary substitute for the

extracellular matrix, and must provide a suitable chemical environment for the proper

development of the cells. In this work, the preparation of a scaffold from

polyhidroxybutyrate (PHB) is presented. This material is biodegradable and its

degradation products can be metabolized by the host through enzymatic processes.

PHB polymeric scaffolds were obtained by the electrospinning technique. The

scaffolds were characterized by ATR-infrared spectroscopy, small angle X-ray

scattering at, confocal Raman-microscopy, differential scanning calorimetry and

scanning electron microscopy.




113

[ BIO-131 ] Scaffolds produced by electrospinning and

modified by plasma for the regeneration of articular

cartilage tissue.

Nancy Cecilia Islas-Arteaga ([email protected]) 3 , Xinah Herón

Gutiérrez García 3 , Atlántida Raya Rivera 2 , Juan Morales-Corona

([email protected]) 1 , Roberto Olayo 1

1 Departamento de Física, Universidad Autónoma Metropolitana, Unidad

Iztapalapa 2 Hospital Infantil de México Federico Gómez, Depto. de Urología, Laboratorio de

Ingeniería de tejidos 3 Posgrado Ingeniería Biomédica, Universidad Autónoma Metropolitana, Unidad

Iztapalapa

In this work scaffolds for tissue engineering were generated by electrospinning

poly(lactic acid) (PLA) and polycaprolactone (PCL). The surface of the scaffolds was

modified with polypyrrole-iodine (PPy-I) by plasma polymerization. The scaffolds

were tested for treatment of chondral generation, showing encouraging results in in

vitro cell growth experiments. The results were evaluated by scanning electron

microscopy (SEM) showing that the pore size and pore size distribution are suitable

for tissue engineering. To improve oxygen diffusion in the scaffolds, aggrecan (AG),

an important component of the extracellular matrix of native cartilage, was added.

The incorporation of AG in the scaffolds was confirmed by attenuated total

reflectance FT-IR and SEM; SEM images show small crystals on the surface of the

scaffolds which we attribute to the sugar content of AG. The scaffolds with AG were

tested both in in vitro cultures and in vivo. The results show cellular growth and

excellent biocompatibility. The mechanical properties of the scaffolds were measured

by tensile tests and the results show promising characteristics for treatment of

chondral defects or injuries.




114

[ BIO-132 ] Comparison study between two pyrrole

polymers synthesized by plasma for biomedical

applications

Omar Fabela-Sánchez ([email protected]) 6 , L. Medina-Torres 2 , S.

Sánchez-Torres 6 , H. Salgado–Ceballos 5 , Axayacatl Morales Guadarrama

1 , Laura Álvarez 6 , Rodrigo Mondragón 6 , Guadalupe Olayo-Gonzalez 4 ,

Guillermo Cruz-Cruz 4 , Araceli Díaz–Ruiz 3 , Camilo Rios-Castañeda 3 ,

Juan Morales-Corona ([email protected]) 6 , Roberto Olayo 6

1 Centro Nacional de Investigación en Imagenología e Instrumentación Médica,

Universidad Autónoma Metropolitana 2 Depto. Ingeniería Química, Universidad Nacional Autónoma de México

3 Depto. Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel

Velazco Suárez S.S.A. 4 Depto. Síntesis y Caracterización, Instituto Nacional en Investigaciones Nucleares

5 Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de

Especialidades, Centro Médico Nacional Siglo XXI 6 Universidad Autónoma Metropolitana, Unidad Iztapalapa

A biomaterial is a material designed to interact with tissues and fluid components of

a host organism. The surface characteristics of biomaterials are key to establish

optimal interactions and to avoid rejection. Our research group has synthesized

plasma-polymerized pyrrole doped with iodine (PPy-I); which has shown excellent

results of biocompatibility in in vitro and in vivo tests. In this work, we vary the

conditions for PPy-I synthesis and analyze the resulting materials measuring contact

angle, XPS, SEM, TEM and the rheological behavior of a suspension of the materials

in bovine albumin. The results of this characterization are discussed with the

perspective of the possible use of the materials as implants.




115

[ BIO-134 ] Scaffolds for artificial skin

Graciela Ruiz-Velazco ([email protected]) 2 , Francisco Martínez-

Flores 1 , Juan Morales-Corona ([email protected]) 2 , Roberto Olayo 2

1 Banco de Tejidos y Piel, CENIAQ-Instituto Nacional de Rehabilitación 2 Departamento de Física, Universidad Autónoma Metropolitana, Unidad

Iztapalapa

Skin injuries may be repaired by treatments that require skin grafts and strict medical

care. The development of these treatments has created a high demand for healthy skin

to be grafted onto the lesions; there is, however, a very limited availability. Tissue

engineering is an alternative that may solve this problem; the combination of

polymeric biomaterials and cell cultures that develop skin-like tissue may be used to

heal or help recover a damaged area. This work presents the development of

poly(lactic acid) scaffolds coated with plasma-polymerized pyrrole doped in situ with

iodine. The scaffolds were characterized by a variety of techniques. Biological

characterization was made by cell cultures of keratinocytes and human fibroblasts

derived from skin.




116

[ BIO-135 ] Biodegradable scaffolds used in endothelial

cell culture

Mario Ramirez-Baez ([email protected]) 3 , Rafael Godínez-

Fernandez 2 , Juan Morales-Corona ([email protected]) 1 , Roberto

Olayo 1

1 Departamento de Física, Universidad Autónoma Metropolitana 2 Departamento de Ingeniería Eléctrica, Universidad Autónoma Metropolitan

3 Posgrado en Ingeniería Biomedica, Universidad Autónoma Metropolitana, Unidad

Iztapalapa

Aliphatic polyesters such as poly(lactic acid) (PLA) and polycaprolactone (PCL) are

used for their biocompatibility and ease of processing in the development of tissue

engineering scaffolds. In this work, these biopolymers were electrospun with a device

that allows for injection in coaxial configuration. Using this configuration we

prepared scaffolds of fibers of PCL and PLA with 50/50 composition. The scaffolds

were characterized by scanning electron microscopy, thermogravimetric analysis,

differential scanning calorimetry, X-ray diffraction, and confocal-raman microscopy.

The scaffolds were also used for growing endothelial cells in a bioreactor.

[ BIO-136 ] Polymeric scaffolds for applications into the

glandular system

Juan Morales-Corona ([email protected]) 1 , Omar Uribe 3 , Rafael

Godinez-Fernández 2 , Atlantida Raya-Rivera 4 , Diego Esquilano-Rendon 4 ,

Roberto Olayo 1

1 Departamento de Física, Área de Polímeros, Universidad Autónoma

Metropolitana, Unidad Iztapalapa 2 Departamento de Ingeniería Eléctrica, Universidad Autónoma Metropolitan

3 Posgrado en Ingeniería Biomédica, Universidad Autónoma Metropolitana 4 Tissue Engineering Laboratory, Infantile Hospital of Mexico, Federico Gómez

Much of the body's organs and their functions are regulated by the glandular system,

is responsible for hormones production. Any alteration in the hormones production




117

can alter or compromise the individual health. In this paper the use of scaffolds

modified by plasma polymerization for use in the glandular system is presented.

Scaffold of polylactic acid and polyglycolic acid coated with a thin film of polypyrrole

doped in situ with iodine, PPy-I, and synthesized by plasma polymerization were

cultured in vitro with both Leydig and Certoli cells to test the production of

characteristic hormone, testosterone. The results indicate that in 1 to 81 days of the

experiment, the cells continue to secrete the appropriate hormone. In another

experiment, PPy-I nonoparticles were synthetized with atmospheric plasma.

Agglomerates of PPy-I nanoparticles were tested in a culture of beta cell in vitro. The

results indicate that beta cells are functional and attached to the PPy-I nanoparticles

support.

[ BIO-137 ] Nanomaterials incorporated into PCL to

modify the biocompatibility.

Erika Fragoso-Pérez ([email protected]) 1 , Roberto Olayo-Valles 1 , Juan

Morales-Corona ([email protected]) 1 , Roberto Olayo 1


Unidad Iztapalapa.

Polymeric scaffolds electrospinning of polycaprolactone, PCL, allow the growth of different

cell types such as hepatocytes, keratinocytes, neurons, etc. To mimic the extracellular matrix

appropriate for the specific cell type to be cultivated should be incorporated into scaffolding

that the cell must be able to use, such as proteins, magnetic nanoparticles or carbon nanotubes

these may give mechanical reinforcement sensibility to electromagnetic signals, a great deal

of work has been done in this direction lately. In this work, the addition of nanomaterials

(carbon nanotubes and magnetic nanoparticles) into PCL electrospun fibers, for increased the

mechanical properties and biocompatibility is presented, samples were characterized by

SEM, Xray diffraction (SAXS and WAXS) and DSC.

Through of electrospinning technique, polymeric PCL scaffolds were prepared with different

concentrations of carbon nanotubes and magnetic nanoparticles embedded in the electrospun

fibers. Once these scaffolds prepared were characterized by XRD, infrared spectroscopy in

ATR mode, the crystallinity was analyzed by DSC, the Confocal- Raman signal is studied

and electron microscopic analysis was performed (SEM).

The authors thank the partial support from CONACyT through project CONACyT-15523

and Electron Microscopy Laboratory of the UAM-Iztapalapa.




118

[ BIO-173 ] Composite fibers of PLA-hydroxyapatite-

carbon nanotubes for biomedical applications

Ramon Román Doval ([email protected]) 2 , Mauricio Ortega

López 3 , Juan Morales Corona 1 , Roberto Olayo Gonzalez 1

1 Departamento de Física Universidad Autónoma Metropolitana, Ave. San

Rafael Atlixco No 186, Iztapalapa, Vicentina, México D. F. CP 09340,

México. 2 Programa de Doctorado en Nanociencias y Nanotecnología. Centro de

Investigación y de Estudios Avanzados del IPN. Av. IPN 2508, San Pedro

Zacatenco, México D.F. C. P. 07360, México. 3 Sección de Electrónica del Estado Solido-Departamento de Ingeniería

Eléctrica. Centro de Investigación y de Estudios Avanzados del IPN. Av.

IPN 2508, San Pedro Zacatenco, México D. F. C. P. 07360, México

The synthesis of carbon nanotubes (CNT) was made in an experimental reactor by the

pyrolysis method. The CNT were purified by oxidation to eliminate the impurities. CNT were

then functionalized to integrate carboxyl groups on the surface. Subsequently composite

fibers were prepared by electrospinning from a solution containing functionalized CNT, poly

(lactic acid) and hydroxyapatite. The composite fibers were characterized by TEM, SEM,

FTIR, SAXS, and Raman-Confocal study. The composite fibers that were prepared could be

used for biomedical applications.




119

[ BIO-174 ] Compatibilizers Use in Silicone-Ceramic

Composites for High Voltage Applications

Daniel Mendoza Gonzalez ([email protected]) 1 , Carlos

Gómez Yáñez 1 , Fermín Pascual Espino Cortés 2

1 Department of Metallurgical and Materials Engineering, ESIQIE. National Polytechnic

Institute, U. P. Adolfo López Mateos, Zacatenco, Mexico City, 07738, Mexico. 2 Graduate Section, Electrical Engineering, ESIME-Zacatenco. National Polytechnic

Institute, U. P. Adolfo López Mateos, Zacatenco, Mexico City, 07738, Mexico.

Nowadays electrical insulators are made of polymer composites because they offer greater

lightness and the processing cost is low, because they not need high energy for the processing,

respect made of ceramic for electrical power systems. Simulations about the distribution of

electrical field in high permittivity non-ceramic insulator shows an important decreasing of

the gradient of electrical field on insulator’s surface, the same that causes the appearance of

leakage current and partial discharges, thus causing the dielectric breakdown of the insulator.

Commonly BaTiO3 (BT) used as filler in silicone matrix due high dielectric constant and

ferroelectric properties. Dispersion of BT particles in silicone and incompatibility of two

surfaces of BT and silicone represents obstacle for obtaining high permittivity composite. On

the one hand the incompatibility causes electric charge gradient interfase between the filler

and the matrix, and their surfaces nature (hydrophilic and hydrophobic respectively) prevent

the increasing of the dielectric constant of the composite to higher values, because there is

no-connection between the ferroelectric filler and the polymer matrix.

The using of Cetyl Trimethyl Ammonium Bromide (CTAB) and Sodium Dodecyl Sulfate

(SDS) as compatibilizers can be a solution to create a connection between the ferroelectric

particles and the polymer matrix for breaking the antagonist condition between both surfaces.

On the other hand maintain a better dispersion of the BT particles can improve the dielectric

constant following the Lichteneker´s law of composites.

In this work a series of settling experiments were conducted in Water/BT/Surfactant systems;

varying the surfactant concentration at fixed values of pH, all according the z potential of the

inorganic filler. Results were analyzed and discussed to determinate the optimal process

coating of BT particles. Studies with TGA-DTA and IR Spectrometry give information and

evidence of the ceramic particles coating with surfactant selected. Furthermore, electrical

simulations in COMSOL were performed to prognosticate the composite´s permittivity by

effect of integration of a compatibilizer; results were analyzed conducting the composite

manufacturing at fixed values of %Vol for BT. Results of electrical characterization was

performed properly, showing an increase in composite’s permittivity due surfactant using




120

without sacrificing high resistivity that the polymer matrix having pure. SEM micrographs

show the perfect integration of the ferroelectric particles in the polymer matrix.

Keywords: Compatibilizer, No-ceramic outdoor insulator, Silicone-ceramic composite.

[ BIO-180 ] Surface functionalization of magnetic

nanoparticles by plasma polymerization

Luis E. González-Calderón ([email protected]) 1 , Anilú Saucedo-

Sariñana 3 , Omar E. Uribe-Juárez 2 , Roberto Olayo 1 , Roberto Olayo-

Valles ([email protected]) 1

1 Departamento de Física, Universidad Autónoma Metropolitana - Unidad Iztapalapa 2 Posgrado en Ingeniería Biomédica, Universidad Autónoma Metropolitana - Unidad

Iztapalapa 3 Universidad Autónoma de Baja California

There is wide interest in the use of magnetic nanoparticles for biomedical applications. The

interaction of magnetic nanoparticles with tissues and cells can be mediated by modifying

the surface of the nanoparticles. Typical methods for surface functionalization of magnetic

nanoparticles include ligand grafting (either chemically or physically) and surface-initiated

polymerization. In this work we demonstrate the possibility of modifying the surface of

magnetic nanoparticles by plasma polymerization. Iron oxide nanoparticles were

functionalized in a low-pressure reactor with a variety of monomers to obtain diverse surface

functionalities. The interaction between the nanoparticles and cells was studied in vitro.

Functionalized magnetic nanoparticles could be used for magnetic separation of cells from

complex mixtures such as blood, and for magnetic fluid hyperthermia treatment of malignant

tissues such as tumors.




121

[ BIO-183 ] Study of the photobactericide properties of

psi layers infiltrated with Ti02 nanoparticles

Karla M. Osorio-Alcántara ([email protected]) 2 , E. Gomez

Barojas 1 , J. Carlos Benitez Serrano 2 , J. Albino Moreno Rodriguez 2 , E.

Sanchez Mora 3 , R. Silva Gonzalez 3

1 CIDS-IC. Ed. 103-C, C.U. BUAP. Puebla, Pue. 72570. 2 Facultad de Ciencias Químicas, BUAP. Puebla, Pue. 72570.

3 Instituto de Física, BUAP. Apdo. Postal J-48, Puebla, Pue. México 72570.

Since Sunada et al [1] discovered the photocatalytic destruction of microorganisms by the

TiO2 the photocatalytic activity of many semiconductors compounds about the pathogenic

micro organisms inhibition effect has been studied. In this work, we studied the

photobactericide properties of porous silicon (PSi) layers infiltrated with TiO2 nanoparticles,

using the E. coli as a biological model. The TiO2 nanoparticles were prepared by the sol-gel

method with a solution that contained 100 mL of 2-propanol (Sigma-Aldrich 99.5%), 10 mL

of deionized water and 5 g of polyvinylpyrrolidone (Sigma Aldrich 10-500G). Then, the

solution was poured into a glass reactor three-ways and it was heated to T=40°C with constant

agitation. Then, the titanium isopropoxide was drop by drop added, heated to 40°C and kept

in agitation for 14 h. The solvent was extracted with a rotary vapor under reduced pressure.

Then, the TiO2 powder was treated thermally at 45°C for 12 h. Furthermore, the TiO2 powder

was grind in a mortar until becoming a fine powder. By SEM the diameter of the TiO2

particles were determined and are of the order of 20 nm. The energy band gap of TiO2

nanoparticles was determined from UV-Vis spectra and the value is of the order of 3.1 eV.

To evaluate the antimicrobial activity of PSi infiltrated with TiO2 nanoparticles some

bioautography trials were done. In agar Müller-Hinton plates, the matrices of proof were

positioned. Later on, the bacterial strain suspension Escherichia coli ATCC 25922 adjusted

to 0.5 of the MacFarland standard was added and incubated at 37°C for 24 h then, the halo

inhibition zone was observed.

Reference

[1] Sunada K, Watanabe T, Hashimoto K. Bactericidal activity of copper-deposited TiO2 thin

films under UV illumination. J. Environ. Sci. Technol. 37 (2003) 4785-4789.

Acknowledgement. This work has been partially supported by VIEP-BUAP, Project GOBE-

EXC15-I.




122

[ BIO-212 ] Synthesis and characterization of N-doped

reduced graphene oxide

Rebeca Ortega Amaya ([email protected]) 3 , Yasuhiro Matsumoto 4 ,

Manuel Alejandro Perez Guzman 2 , Roberto Olayo Gonzalez 1 , Juan

Morales Corona 1 , Mauricio Ortega Lopez 3

1 Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, Apto. Postal 55-534,

CP 09340, México D.F., México 2 Programa de Doctorado en Nanociencias y Nanotecnología. CINVESTAV IPN, Av. IPN No. 2508,

CP 07360, México D.F., México. 3 Sección de Electrónica del Estado Sólido, Departamento de Ingeniería Eléctrica, CINVESTAV, .

Av. IPN No. 2508, CP 07360, México D.F., México 4 Sección de Electrónica del Estado Sólido, Departamento de Ingeniería Eléctrica, CINVESTAV.

Av. IPN No. 2508, CP 07360, México D.F., México

Now a days, graphene-based materials, including graphene oxide (GO), the oxidized forms of

graphene, are under study because of their biocompatibility and unique physicochemical properties

[1]. They are currently studied for applications in the technological areas of biomedicine, energy

production, electronics and environmental remediation[2]. Reduced GO (rGO) has been applied in

bone implants and bone tissue engineering, due their exceptional mechanical properties[3], and

recently, nitrogen doped graphene was successfully proven as a useful sensing and electronic

biomaterial, particularly, as a glucose biosensor[4].

In this work, we report our results on the synthesis and characterization of nitrogen (N) doped reduced

graphene oxide (N-rGO). GO was first obtained by Hummer´s method and the resultant product was

treated under a N2(g) plasma at different times. The samples were characterized by Raman

spectroscopy and X-ray photoelectron spectroscopy (XPS).

The XPS spectrum displays characteristics bands corresponding to quaternary N (or graphitic N),

pyridinic N, and pyrrolic N. Remarkably, the N2 plasma processing simultaneously promotes the GO

reduction and the N-doping.

[1] W. Choi, I. Lahiri, R. Seelaboyina, and Y. S. Kang, "Synthesis of Graphene and Its Applications:

A Review," Critical Reviews in Solid State and Materials Sciences, vol. 35, pp. 52-71, 2010/02/11

2010.

[2] C. Chung, Y.-K. Kim, D. Shin, S.-R. Ryoo, B. H. Hong, and D.-H. Min, "Biomedical Applications

of Graphene and Graphene Oxide," Accounts of Chemical Research, vol. 46, pp. 2211-2224,

2013/10/15 2013.

[3] L. Bacakova, I. Kopova, L. Stankova, J. Liskova, J. Vacik, V. Lavrentiev, et al., "Bone cells in

cultures on nanocarbon-based materials for potential bone tissue engineering: A review," physica

status solidi (a), vol. 211, pp. 2688-2702, 2014.




123

[4] M. M. Barsan, M. David, M. Florescu, L. Ţugulea, and C. M. A. Brett, "A new self-assembled

layer-by-layer glucose biosensor based on chitosan biopolymer entrapped enzyme with nitrogen

doped graphene," Bioelectrochemistry, vol. 99, pp. 46-52, 10// 2014.

[ BIO-213 ] Synthesis and characterization of

superparamagnetic cubical magnetite nanoparticles

Manuel Alejandro Pérez Guzmán ([email protected]) 3 , Jaime

Santoyo Salazar 1 , Enrique Campos Gonzalez 1 , Rebeca Ortega Amaya 4 ,

Yasuhiro Matusmoto 4 , Omar Felipe Fabela Sanchez 2 , Roberto Olayo

Gonzalez 2 , Juan Morales Corona 2 , Mauricio Ortega Lopez 4

1 Departamento de Física, CINVESTAV IPN. Av. IPN No. 2508, CP 07360, México D.F.,

México. 2 Departamento de Física, Universidad Autónoma Metropolitana Iztapalapa, Apto. Postal

55-534, CP 09340, México D.F., México 3 Programa de Doctorado en Nanociencias y Nanotecnología. CINVESTAV IPN. Av. IPN

No. 2508, CP 07360, México D.F., México. 4 Sección de Electrónica del Estado Sólido, Departamento de Ingeniería Eléctrica,

CINVESTAV IPN, . Av. IPN No. 2508, CP 07360, México D.F., México

Magnetite nanoparticles are under study due their biocompatibility, physicochemical and

magnetic properties, they have applications in many technological areas like biomedical,

electronics, energy and environmental remediation1. This work presents our recent advances

on the synthesis and characterization of oleic-stabilized cubical magnetite nanoparticles

prepared via an organic synthetical method. The nanoparticle morphological, structural and

magnetic properties were characterized by TEM, XRD, and VSM. TEM revealed well-

crystallized and monodisperse 12 nm in size magnetite nanoparticles. The magnetite phase

was corroborated by XRD. The hysteresis loop revealed the superparamagnetic character of

our nanomaterial.The nanoparticles are suitable to be used on catalysis, bioremediation and

hyperthermia cancer treatment2.

1. Lu, A., Magnetic Nanoparticles: Synthesis, Protection, Functionalization, and

Application. Angewandte Chemie, 2007(46): p. 1222-1244.

2. Reiss, G., Magnetic Nanoparticles, in Handbook of Nanophysics: Nanoparticles and

Quantum Dots. 2010, CRC Press. p. 2-1-2-13.




124

[ BIO-231 ] Electrospinning process optimization in

obtaining nanofibers by response surface methodology

(RSM) for applications in tissue engineering skin

Josué Jiménez Vázquez ([email protected]) 1 , Eduardo San Martin

Martinez 1

1 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del Instituto

Politécnico Nacional, Legaria 694. Colonia Irrigación, 11500 México D. F.

The electrospinning enables the production of polymeric nanofibers with diameters ranging

from 3nm to 5um. Potential applications of the nanofibers produced by electrospinning

include filtration membranes, catalytic nanofibers, fiber-based biosensors, and scaffolds for

tissue engineering. For the study of the factors in the synthesis of nanofibers biopolymer

(gelatin type B) through electrospinning, varying the parameters of solution concentration

(% w / v), voltage (kV), distance from the tip of the needle to the collector (cm) and flow (ml

/ h). A central composite design (CCD) was used and diameter nanofibers variation was

evaluated in each experiment by means of scanning electron microscopy (SEM). With data

obtained a statistically adjusted mathematical model was performed which was used to obtain

the surface response via Design Expert 7.0 software. The least significant parameters in the

CCD were voltage and distance from the needle tip to collector, so these were held constant

to determine nanofibers gelatin diameter response surface. The most significant parameters

were solution concentration and biopolymer flow. It was determined through the response

surface that the average diameter of the nanofibers increases with rising gelatin concentration

to solution. It was found that the smaller diameter of the nanofibers can be obtained at a

concentration of 10% (w / v) gelatin and a flow of 4 mL / h.




125

[ BIO-235 ] Experimental and Theoretical Analysis of

Cellulose Nanowhiskers/Poly (Butyl Acrylate)

Nelly Flores-Ramirez ([email protected]) 2 , Maria Guadalupe Pineda-

Pimentel 2 , Salomon Ramiro Vasquez-Garcia 1 , Lada Domratcheva-Lvova 2

, Leandro García-Gonzalez 3 , Juan Carlos Farías Sanchez 2

1 Department of Chemistry Universidad Michoacana de San Nicolás de Hidalgo, Morelia,

Mich. 58060, México 2 Department of Wood Engineering and Technology Universidad Michoacana de San

Nicolás de Hidalgo, Morelia, Mich. 58060, México 3 Research Center in Micro and Nanotechnology of the UV Boca del Rio, Veracrúz, 94292,

México

Cellulose is an abundant polymer that can be obtained via numerous resources like plants,

algae. Among various organic materials, cellulose is the most appropriate polymer to prepare

various types of nanomaterials, has a nanostructured organization and unique properties;

currently cellulose nanowhiskers (CNW) which are the highly ordered crystalline regions

had been used as reinforcing material. The aim of this study was to investigate the miscibility

between two components in a blend: nanowhiskers of cellulose (CNW) on poly(butyl

acrylate) (PBA). These are an analysis of molecular configuration, orientations and

intermolecular interactions in order to determine the adhesion and mechanical properties of

materials obtained. Using acid hydrolysis CNW were prepared from wood cellulose, while

the PBA was synthetized from solution polymerization. Additionally, CNW/PBA integration

was carry out by incorporating CNW (0.1 and 0.5 wt%) into a PBA matrix. Then, the

products were analyzed through molecular simulation (Accelrys Materials Studio) and a

further analysis using (ATR) spectroscopy was for correlating results. The molecular

simulation confirmed the existence of intra and intermolecular interactions in the systems

analyzed and the cellulose exhibited molecular and flat linearity indicative cellulose

crystallinity. Additionally intermolecular hydrogen bonding interactions and van der Waals

forces were determined when the PBA was coupled to the Cellulose.




126

[ BIO-236 ] Interfacial Analysis of Chitosan/Bone:

Cortical and Cancellous Bone matrices

Christian Vianey Paz-Lopez 1 , Salomon Ramiro Vasquez-Garcia 1 , Nelly

Flores-Ramirez ([email protected]) 2

1 Department of Chemistry Universidad Michoacana de San Nicolás de Hidalgo,

Morelia, Mich. 58060, México 2 Department of Wood Engineering and Technology Universidad Michoacana de

San Nicolás de Hidalgo, Morelia, Mich. 58060, México

The stability and separation performance of a film can be tune by interfacial

compatibility and interactions between the active film and the support. Considering

the bioadhesion phenomena and principles, chitosan was used directly as the active

layer in this study due to its superior film forming property and multiple interactions

with bone. There were analyzed two types of bone substrates: cancellous and cortical

bones. Thus, chitosan/bone samples were prepared by controllable dip-coating

method under mild conditions. Experimental investigation was utilized to probe the

interfacial compatibility and interaction of the chitosan with the bone substrates.

Fourier transform infrared spectroscopy data revealed the strong interaction between

the chitosan molecules and the substrate. Scanning electron microscope and

microhardness analysis showed a moderate interfacial compatibility, while analysis

by X-ray diffraction were used to identify the chitosan spatially structure, which

increased their order on bone as a result of the increased acidity.




127

[ BIO-278 ] Evaluation of reactive resin on adhesive

formulation of pressure sensitive adhesives

Tzeitel Hernández Martínez ([email protected]) 1 , José Luis Rivera

Armenta ([email protected]) 1 , Beatriz Adriana Salazar Cruz 1 ,

María Yolanda Chávez Cinco 1 , Ulises Paramo-García 1

1 División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Ciudad

Madero

In developing adhesives it has been interest in incorporation or replace materials in

the formulations to improve the performance thereof in accordance with the

requirements of application, being more acceptable environmentally friendly

materials. The adhesive performance is affected by the adhesive and cohesive

properties that can be optimized by suitable selection of polymer, the nature or amount

of adhesive resin and additive presences. In the present research, two styrene-

butadiene-styrene (SBS) copolymer, one linear and one radial structure, in

formulation of solvent-based contact adhesive were studied. The aim of use SBS

copolymer, is to avoid the use of halogenated polymers in adhesive formulations due

environmental regulations. Solubility tests in different solvents combination and

suitable combination was selected according with hildebrand solubility parameter. To

prevent precipitation of additives in adhesive formulation, an ultrasonic agitation was

carried out before mixing the whole formulation. brookfield viscosity of adhesive

formulation was determinated to identify the optimal polymer chains diffusion in the

system and the adequate reactive resin amount. Rheological measurements were

carried out to evaluate elastic modulus. Finally all characterization results were

compared with commercial adhesive in order to assess the performance.




128

[ BIO-283 ] Thermal behavior effect of mix asphalt

modified with radial SBS-Nanoclay composite

Daniel Anzures 2 , Beatriz Adriana Salazar Cruz

([email protected]) 1 , José Luis Rivera Armenta

([email protected]) 1 , Nancy Patricia Díaz Zavala 1 , Ana

María Mendoza Martínez 1

1 División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Ciudad

Madero 2 Instituto Tecnológico de Ciudad Madero

The aim of present work was to evaluate the effect of adding of a nanocomposite obtained

from an elastomeric matrix (radial styrene-butadiene-styrene copolymer, sbs) and a

montmorillonite clay modified with a quaternary ammonium salt (cloisite 15a), to a virgin

asphalt. the modifier (sbs-cloisite 15 a nanocomposite) was added in different amounts (up

to 6% ) to asphalt. The asphalt properties such as viscosity and the thermal stability which

influences the improvement of the failures as cracking and fatigue ressistence, increases with

modifier addition. The obtained results of asphalt mixtures, show improvements in

conventional properties such as penetration, softening point and thermal susceptibility. The

thermal stability results shows that high temperature storage is stable when modifier is

present in 4%. The rheological properties of asphalt-modifier mixtures were evaluated using

a dynamic shear rheometer. The results show an improve in rheological properties compared

with virgin asphalt, such as increasing elastic response (increase in complex modulus and

decrease in the phase angle) evaluated at high temperature. The failure temperature was

determinated by means on the guidelines of shrp standard getting higher values than virgin

asphalt, proving therefore be a viable option to add the modifier to virgin asphalt.




129

[ BIO-316 ] Roll of solution and parameters deposition on

PVP diameter nanofibers by electrospinning.

Nadia Cruz Gonzalez ([email protected]) 1 , Jorge Roque de la

Puente 2 , Miguel Angel Meléndez Lira 1

1 Department of Physics, CINVESTAV-IPN, Av. Instituto Politécnico Nacional 2508, col. San Pedro

Zacatenco, Delegación Gustavo A. Madero, México D.F. C.P. 07360 2 Laboratorio Avanzado de Nanoscopía Electrónica – LANE-CINVESTAV, Av. Instituto Politécnico

Nacional 2508, col. San Pedro Zacatenco, Delegación Gustavo A. Madero, México D.F. C.P.

07360

Electrospinning is a simple technique that has gained much attention because of its capability and

feasibility in the fabrication of large quantities of fibers from polymer with diameters ranging in nano-

microscale [1,2]. These fibers provided high surface area to volume ratios, and it was of considerable

interest for many applications, such as nanoparticle carriers in controlled release, scaffolds in tissue

engineering, wound dressings, military wear with chemical and biological toxin-resistance,

nanofibrous membranes or filters, and electronic sensors [3]. In a typical process, a polymer solution

or melt is injected from a small nozzle under the influence of an electric field as strong as several

kV/cm. The build up of electrostatic charges on the surface of a liquid droplet induces the formation

of a jet, which is subsequently stretched to form a continuous ultrathin fiber. In the continuous-feeding

mode, numerous copies of fibers can be formed within a period of time as short as a few seconds.

characteristics such as fiber diameter, fiber morphology and the density of beads are strongly

depending on the solution concentration, viscosity, surface tension and conductivity and process

variables, such as applied voltage, needle diameter, flow rate and needle-to-collector distance. PVP

exhibits unique properties, including solubility in water or in organic solvent. It has also very low

toxicity, high complexing ability, good film forming characteristics and adhesive properties.

Therefore PVP are widely used as polymer solution in to TiO2 and MoS2 nanofiber because is

compatible with several Titanium and Molybdenum precursors. In the present work, PVP fibers with

8, 11 and 15 % weight using ethanol and DFM as solvent were prepared. Parameter deposition such

as distance, high voltage needle diameter and flow rate were varied. Nanofibers obtained were

characterized by Scanning Electron Microscopy.

This work was financed by CONACYT project number CB2010-154857 and CONACYT

postdoctoral fellow second call 2014, Referencia: CVU No.218308.

[1]J. Doshi, D.H. Reneker, Electrospinning process and applications of electrospun fibers, J.

Electrostat. 35 (1995) 151–160.

[2] D.H. Reneker, I. Chun, Nanometre diameter fibres of polymer, produced by electrospinning,

Nanotechnology 7 (1996) 216–223.

[3] T. Kongkhlang, K. Tashiro, M. Kotaki, S. Chirachanchai, Electrospinning as a new technique to

control the crystal morphology and molecular orientation of polyoxymethylene nanofibers, J. Am.

Chem. Soc. 130 (2008) 15460–15466.




130

[ BIO-320 ] Characterization of the behavior of PPy-I in

solutions of albumin and its application in a model of

traumatic spinal cord injury.

Omar Felipe Fabela-Sanchez ([email protected]) 4 , Luis Medina-

Torres 5 , Stephania Sánchez-Torres 2 , Hermelinda Salgado–Ceballos 8 ,

Hermelinda Salgado–Ceballos 1 , Ana Laura Alvarez 4 , Rodrigo

Mondragon 7 , M Guadalupe Olayo 7 , Guillermo J Cruz 7 , Juan Morales 3 ,

Araceli Díaz-Ruiz 6 , Camilo Rios 6 , Roberto Olayo 3

1 Centro de Investigación del Proyecto CAMINA A.C., México. 2 Depto. Biología Celular, Universidad Autónoma Metropolitana, México.

3 Depto. Física. Universidad Autónoma Metropolitana, México. 4 Depto. Ingeniería Eléctrica. Universidad Autónoma Metropolitana, México.

5 Depto. Ingeniería Química, Universidad Nacional Autónoma de México, México. 6 Depto. Neuroquímica, Instituto Nacional de Neurología y Neurocirugía Manuel Velazco

Suárez S.S.A. México. 7 Depto. Síntesis y Caracterización, Instituto Nacional en Investigaciones Nucleares,

México. 8 Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de

Especialidades, Centro Médico Nacional Siglo XXI, México.

Pyrrole is one of the most widely used monomers due to their easy availability, chemical

stability and polarizability. It is therefore easy to obtain pyrrole derivatives by polymerization

by synthetic methods such as: chemical, electrochemical and plasma energy; whereby it is

possible to obtain surface coverages that have a wide variety of functional groups that make

polypyrrole a good candidate for immobilization and / or coupling of biomolecules of interest

in biomedical applications. In this study, we focused on presenting the characterization of

iodine-doped polypyrrole (PPy-I) synthesized by plasma energy using techniques of study as

XPS, SEM and TEM; as well as their rheological behavior as particles suspended in solutions

of albumin (ALB) at different concentrations and two test temperatures. With the data

obtained was possible to establish the PPy-I/ALB relationship to be supplied in a model of

traumatic spinal cord injury in Long Evans rats strain in which functional recovery was

evaluated by the Basso, Beattie, Bresnahan (BBB) scale.




131

[ BIO-332 ] Structure and interaction mechanism of a

polyelectrolyte complex using dissipative particle

dynamics.

Efrain Meneses-Juárez ([email protected]) 1 , César Márquez-

Beltrán 1 , Juan Francisco Rivas-Silva 1 , Umapada Pal 1 , Minerva

González-Melchor 1

1 Instituto de Fisica de la Benemerita Universidad Autonoma de Puebla. Av. San Claudio y

Blvd. 18 sur. Col. San Manuel. Ciudad Universitaria. C.P. 72570

The mechanism of complex formation from tow oppositely charged linear polyelectrolytes

dispersed in a solvent is investigated by using dissipative particle dynamics simulation. In

the polyelectrolyte solution the size of the cationic polyelectrolyte remains constant while

the size of the anionic chain increases. We analyze the influence of the anionic

polyelectrolyte size and salt effect on the conformational changes of the chains when the

complex is forming. The behavior of the radial distribution function, the end-to-end distance

and the radius of gyration of each polyelectrolyte is examined. These results showed that the

effectiveness of the complex formation is strongly influenced by the process of counterion

release from the polyelectrolyte chains. Depending on the ratio of chain lengths, we have

found that the formation of a compact complex or a lengthened structure can occur.




132

[ BIO-353 ] Behaviour of the compressive strength in

modified mortars elaborated with recycled materials

(aggregates and PET resin)

Jose Ramon Orduño Apodaca ([email protected]) 2 , Jose Manuel Gomez Soberon

1 , Ramon Corral Higuera 2 , Susana Paola Arredondo Rea 2 , Andres Castro Beltran 2 ,

Ramon Alvaro Vargas Ortiz 2 , Jorge Luis Almaral Sanchez ([email protected]) 2

1 Departamento de Construcciones Arquitectónicas II Av. Doctor Marañón 44-50, 08028.

Barcelona. España 2 Universidad Autónoma de Sinaloa Facultad de Ingeniería Mochis Fuente de Poseidón y

Prol. Ángel Flores S/N Fracc. Las Fuentes Los Mochis, Sinaloa, México

The problem of recycling waste materials of various kinds, is, and will be, undoubtedly, one

of the problems that will most affect the society in the future and that we must address and

resolve in all possible ways. Soft drink and mineral water bottles are all made of polyethylene

terephthalate (PET) and constitute the third largest food packaging consumed. The

production of such a large amount of PET bottles has created an environmental problem of

gigantic proportions, since these bottles not reused become as plastic waste, which do not

decompose readily in nature. To solve this problem is possible to recycle these post-consumer

PET bottles. The demolished concrete to serve as a source as quality aggregate feed stock in

a variety of applications. Such recycling operations have the added benefit of reducing

landfill disposal, while conserving primary resources and reducing transport costs. Recycled

demolition aggregate used to replace newly quarried limestone aggregate, usually used in

coarse (6 mm) and fine (4 mm-to-dust) grading.

This research focused on explaining the mechanical effects caused by addition of unsaturated

polyester resin made from post-consumer bottles of PET (R-PET), cement-R- PET pastas

and polymer modified mortars (PMM) with total or partial substitution of the recycled fine

aggregate (RA) and additions of R-PET. The TGA and XRD results show that there is less

development of the hydration products to a higher content of R-PET, causing reduction in

the compressive strength of the PMM.




133

[ BIO-390 ] Thin films of polyaniline-TiO2 using

synthesis by plasma

Cuauhtémoc González Palacios ([email protected]) 3 ,

Elena Colín Orozco 3 , Guillermo Cruz Cruz 1 , Guadalupe Olayo González 1

, Juan Morales Corona 2 , Iván Martínez Cienfuegos 4

1 Departamento de Física, Instituto Nacional de Investigaciones Núcleares, ININ 2 Departamento de Física, Universidad Autónoma Metropolitana,UAM-IZTAPALAPA

3 Facultad de Ingeniería, Universidad Autónoma del Estado de México, UAEMex 4 Facultad de Ingeniería, Universidad Autónoma del Estado de México,UAEMex

Is currently seeking new materials with higher efficiency in absorption of solar energy for

application in solar cells, an example of these are the matrix composite polymer-

semiconductor for the application. Polymer conjugates with a full load balancing only will

be a semiconductor, i.e. it must have a gap of energy between the valence band and the

conduction, however breaks the energy balance through oxidation or reduction of electron,

increases the number of carriers and the electrical conductivity is favored by several orders

of magnitude. This paper reports the synthesis and characterization of films composed of

polyaniline-TiO2 (PAn/TiO2) using the technique of synthesis by plasma, and the analysis of

their morphological properties, through scanning electronic microscopy and optical,

functional groups present on the surface with an analysis of infrared spectroscopy, and

electrical conductivity as a function of temperature. The results show films with agglomerate

formation and the incorporation of TiO2on the surface of the polymer. The electrical

conductivity was favoured by an order of magnitude that is due to the presence of functional

groups in the surface.




134

[ BIO-391 ] Activation energy of thin films of doped

fullerenes polypyrrol (PPy/C60-C70)

Elena Colín Orozco ([email protected]) 3 , Cuauhtémoc Palacios

González 3 , María Guadalupe Olayo González 1 , Guillermo Cruz Cruz 1 ,

Juan Morales Corona 2 , Miriam Sánchez Pozos 3

1 Departamento de Física, Instituto Nacional de Investigaciones Núcleares, ININ 2 Departamento de Física, Universidad Autónoma metropolitana, UAM-IZTAPALAPA

3 Facultad de Ingenieria, Universidad Autónoma del Estado de México, UAEMex

Recently, polymers have been used as matrix for the development of composite materials

due to the good adhesion with other elements, resistance to corrosive environments and

electrical conductivity. When joins them to the polymer chain any other material in this case

Fullerenes are structural, electronic and spectroscopic properties that can be studied in the

obtaining of composites and thin films that improve efficiency. The objective of this work is

to study the activation energy of compounds of PPy /C60 -C70 synthesized by polymerization

technique by plasma to different power values. We report the synthesis and characterization

of thin films, the study of the electrical properties, structural composition using the electronic

microscopy: scanning and optics, as well as thermogravimetric analysis. The results show

the formation of films with crowds on the surface. The electrical conductivity was favoured

up to orders of magnitude, while de activation energy was 0.34 - 0.54 eV for each the

compounds synthesized.




135

[ BIO-417 ] Modifying the surface of the macroporous

silicon for use in biosensors.

Xairo León Valiente ([email protected]) 1 , Ana Maria Gennaro 2 , Edith

Osorio de la Rosa 1 , Hector Juárez Santiesteban 1 , Mauricio Pacio Castillo

1 , Roberto Roman Koropecki 2

1 Centro de Investigación en Dispositivos Semiconductores, Universidad Autónoma de

Puebla CIDS-ICUAP 2 Grupo de Semiconductores Nanoestructurados, Instituto de Física del Litoral (CONICET-

UNL)

In this paper the results of surface functionalization of macroporous silicon substrates are

presented. It is intended to introduce lipids in the form of liposomes, lipid bilayers to build

on the inner surface of the pores, for which the surface should be hydrophilic. It seeks to

achieve this by oxidizing the surface so incorporated in the form of HO- hydroxyl radicals.

Initially the macro-porous silicon is obtained from the anodising a silicon wafer

monocrystalline p-type with (100) orientation and resistivity of 30-50 Ω-cm, in a solution of

HF (50%) and dimethylformamide (DMF) by volume (1: 9). A current density of 10 mA/cm2

was used, anodization time was 1500 s. After anodising the surface of the sample was

subjected to functionalization, four methods, (1) a solution of tetrabutylammonium

hydroxide (HTBA) 1% was used, (2) the sample was placed in a solution of hydrogen

peroxide (H2O2) 30% w / V, (3) the functionalization was performed using rapid thermal

annealing (RTA) and (4) in a solution of 1% KOH for 60 seconds. Functionalization

posttreatment samples were characterized by infrared Fourier transform spectroscopy

(FTIR). The FTIR spectra of all the samples show the characteristic peak of hydroxyl groups

(OH) 3000 cm-1. The introduction of liposomes was verified by FTIR spectroscopy, which

proves hydrophilicity. A systematic study varying the conditions and methods of oxidation

was performed. EPR spectroscopy and theoretical-experimental settings the amount of lipids

forming lipid bilayers at the surface of the pores and the amount of lipids remained in the

form of unilamellar liposomes were obtained.

Keywords: Silicon macroporous, Lipids, functionalization




136

[ BIO-434 ] Biosensor development using gold

nanoparticles and lectins

Angel Netzahual Lopantzi 1 , Jose Francisco Sanchez Ramirez 1 , Orlando

Zaca Moran 1 , Abdu Orduña Diaz 1 , Marlon Rojas Lopez 1 , Raul Delgado

Macui 1 , Valentin Lopez Gayou ([email protected]) 1 , Julio Reyes

Leyva 2

1 CIBA-IPN, Tlaxcala, 90700, Mexico 2 CIBIOR-IMSS Metepec, Puebla, Méx.

A biosensor is a device integrated of a biological recognition element and transductor that

provide qualitative or quantitative information, between they there are biosensors optics that

provide information spectroscopy such as fluorescence, absorption, scattering and reflection.

These biosensors have been applied in areas such as security food, environmental and

biomedical. These biosensors used different molecules (biological recognition element) that

have ability to detect of mode specifically and high sensitivity other molecules. So that the

assembly of these biosensors is critical to get optimal results; in this work we develop an

experimental protocol for assembly a biosensor integrated of gold nanoparticles (transductor)

coupled to lectins (biological recognition element). Gold nanoparticles were obtained by

reduction method in presence ions metals and using chitosan as agent reductant and stabilizer,

this polymer has capacity of functionalized surface nanoparticles with group’s hydroxyls

which allow us to bind the lectin. The assembly between the nanoparticle and the lectin was

realized to pH 7. Each stage including the synthesis, the conditioning and the assembly of

lectin was analyzed by applying UV/Vis and Infrared spectroscopy, together with

Transmission Electron Microscopy (TEM).




137

[ BIO-453 ] Methodology to obtain hydroxyapatite with

different crystalline quality of pork bone

Andrea Yáñez ([email protected]) 2 , Mario Enrique Rodriguez Garcia


1 Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional

Autónoma de Mexico Campus Juriquilla, Qro., Mexico 2 Ingenieria Física, Faculta de Ingeniería, Universidad Autónoma de

Queretaro

Bio-ceramics are biomaterials whose main characteristic is that can be use in medicine, for

example, in prosthesis. Hydroxyapatite is a bio-ceramic composed by calcium, hydrogen,

oxygen and phosphorus, which chemical formula is (Ca10[PO4]6[OH]2). In nature it could be

find in bones of vertebral animals, dentin and exoskeletons.

In this project crystal hydroxyapatite will be obtain using cortical pork bone found in the

femur. The methodology that was used to obtain hydroxyapatite consist in a hydrothermal

and calcination process, the objective is that no chemicals will be used in the process. The

steps to obtain hydroxyapatite will be separated in four sections, each one with a description.

1. First clean

o Cook the cortical pork bone with distilled water using a pressure cooker, it

will be easier to take off the meat that the bone may have.

o When the bones doesn’t have meat, put them to dry in an oven for 6 days,

with constant temperature 90°C.

o Take out the bones and cook them with distilled water using a pressure cooker.

o After 1 hour of being in the pressure cooker, put them to dry in an oven for 1

day at 90°C.

2. Pulverization

Using a metal mortar hit the bones until they have a size of 5 mm.

With a rock miller the bones are milling in order to obtain powder.

Homogenize the powder of bone using an 80 mesh sieve.

3. second clean

When the powder is already homogeneous it will have a second clean.

Cook the powder with distilled water at 1:10 in a pressure cooker, for 6 minutes,

trying to lost the smallest amount of powder.




138

Dry the powder in an oven with a temperature of 90°C, for 1 day.

4.Incineration

In this step two variables are controlled: incineration time and heating rate, following

the next steps:

Increase the temperature with a velocity of 5°C per minute until it reach 600°C.

Incinerate for 3 hours at this temperature, them change the velocity of heating rate to

2.5 , 5.0, and 7.7 °C/min up to 700, 800, 900, and 1000 °C.

In this work we obtained hydroxyapatite without any chemical reaction and different

crystalline qualities just controlling the time of calcination and the velocity of the ramp of

heating.

[ BIO-456 ] Granular formation’s kinetic of BIO-HAP in

function of temperature

Sandra Milena Londoño Restrepo 1 , Mario Enrique Rodriguez Garcia




Hydroxyapatite (Hap) is a stoichiometric material with formula: Ca10(PO4)6OH2, while,

biohydroxyapatite (Bio-Hap) is a non-stoichiometric ceramic that contain mineral traces,

such as, Na, K, Cr, Fe, Mg, Mn, and others. The importance of Bio-Hap is growing due to

medical applications, like, maxillofacial surgery, coating metallic implants, dental fillings,

and others. In addition, HAp is employed in chromatography, catalysis, and genomic

medicine. In this work, the effect of heating rate on granular formation’s kinetics of Bio-

HAp was studied. To determine the effects on physicochemical properties, the biologic

material (bovine bone powder) was calcined at 600, 700, 800, 900, 1000, and 1100°C,

employing two different heating rates (2.5 and 5 °C/min), and a characterization point to

point was performed. The HAp sample taken from bovine bone was obtained by

hydrothermal process and calcination. Physicochemical properties characterization was

realized by different methods like X-ray diffraction (XRD), Raman spectroscopy, Scanning

Electron Microscopy (SEM), Thermogravimetric analysis (TG) and Inductively Coupled

Plasma Optical Emission Spectroscopy (ICP-OES). XRD was used to study the structural

behavior as well as the crystalline quality. Raman was carried out in order to identify the




139

functional groups of HAp and monitor the removal of organic material. The surface

morphology was analyzed by SEM. Thermal degradation was established by TG and ICP-

OES was used in order to establish the elemental composition. We found that high

temperatures and slow heating rates produce a single crystal of Bio-Hap with high crystalline

quality of hydroxyapatite.

Keywords: Hydroxyapatite, heating rate, crystalline quality, kinetic.

References

Akram M., Ahmed R., Shakir I., Wan Ibrahim W.A., Hussain R. (2014). Extracting

hydroxyapatite and its precursors from natural resources. Journal of Material Science,

49, 1461–1475.

Campa Molina J., Ulloa Godínez G.S., Bucio Galindo L., Belío I.A., Velazquez R.,

Rivera Muñoz E.M. (2007). Biomateriales: Fundamentos, técnicas y aplicaciones.

Universidad de Guadalajara, México.

Kusrini E., Sontang M. (2012). Characterization of x-ray diffraction and electron spin

resonance: Effects of sintering time and temperature on bovine hydroxyapatite.

Radiation Physics and Chemistry, 81, 118–125.

Sofronia A.M., Baies R., Anghel E.M., Marinescu C.A., Tanasescu S. (2014).

Thermal and structural characterization of synthetic and natural nanocrystalline

hydroxyapatite. Materials Science and Engineering C, 43, 153–163.




140

[ BIO-474 ] manufacture of membranes of a-SiC:H for

biosensor applications

Oscar Mauricio Gelvez Lizarazo ([email protected]) 2 , José

Herrera-Celis ([email protected]) 2 , Claudia Reyes-Betanzo 2 , Abdu

Orduña-Díaz 1

1 Centro de Investigación en Biotecnología Aplicada del Instituto Politécnico Nacional, Ex-

Hacienda San JuanMolino Carretera Estatal Tecuexcomac-Tepetitla Km 1.5, C.P. 90700,

Tlaxcala-México 2 Electronics Department, National Institute of Astrophysics, Optics and Electronics

INAOE, Luis Enrique Erro 1, Santa María Tonatzintla, 72840 Pue

In order to develop biosensors based on membranes, a-SiC:H films has been deposited by

PECVD on silicon substrate, the residual stress of the films has been reduced through a

annealing, and wet and dry etching of silicon has been made. Characterization of the residual

stress and roughness of the deposited films was performed using surface profilometry and

atomic force microscopy, respectively. By the annealing at 450 °C under nitrogen

atmosphere, residual stress was reduced by 75%, improving the structural stability of the

membranes. The etch rates of silicon with hydrofluoric acid, potassium hydroxide and HNA

solutions (HF+HNO3+CH3COOH) were obtained, resulting in a etch rate as high as 18.6

μm/min. The dry etching was made using SF6 as precursor gas and a etch rate of 5.44 μm/min

was achieved in this case.

Finally, the a-SiC:H biocompatibility was assessed by testing the bacterial attachment of

gram negative bacillus using Enterotoxigenic Escherichia coli (ETEC), proving the non-

toxicity and the good adhesion of the biological agent with the material.

Acknowledgment

The authors are thankful to Mayra Gonzalez Quintero and Dra. Elsa Iracena Castañeda

Roldán by for their cooperation and support in the process of fixing bacteria developed in

Laboratorio de patogenicidad microbiana del Departamento de Investigaciones

Microbiológicas en el Instituto de ciencias de la Universidad Autónoma de Puebla (ICUAP).




141

[ BIO-513 ] Chitosan films composites with the sistem

hydroxyapatite/ silver phosphate.

Gerardo Pozos Sanchez ([email protected]) 3 , Efraín Rubio Rosas

([email protected]) 1 , Erick Reyes Cervantes 2

1 Centro Uiversitario de Vinculación y Transferencia de Tecnología Prolongación de la 24

Sur y Av. San Claudio, Ciudad Universitaria, Col. San Manuel, 72570 Heróica Puebla de

Zaragoza, Pue. 2 Centro Universitario de Vinculación y Transferencia de Tecnología Prolongación de la

24 Sur y Av. San Claudio, Ciudad Universitaria, Col. San Manuel, 72570 Heróica Puebla

de Zaragoza, Pue. 3 Facultad de Ingeniería Química BUAP, Edificio 105 H, Prolongación 14 Sur s/n, Ciudad

Universitaria, 72570 Heróica Puebla de Zaragoza, Pue.

Chitosan and hydroxyapatite are materials that be found inside of the human body, but it

doesn’t have a good antimicrobial activity, if silver phosphates is added it can be inhibit

growth of some kind of bacteria, proposing a possible application as a material for bone

filling or bags for sterilization of material for laboratory. The aim of this work was the

synthesis and characterization of composite films of chitosan with hydroxyapatite and silver

phosphate system. The first step was the synthesis of hydroxyapatite (Hap) by the

precipitation method, the second step was the precipitation of silver phosphate Ag3PO4, once

they obtained the system chitosan films were made with this ceramic material, to different

concentrations of Hap/Ag3PO4 (0, 50 y 70%), for comparison therebetween. The preparation

of the films was by varying the pH, thereby achieving obtain firm and flexible films. XRD

to characterize the films was performed to confirm the presence of crystals of Ag3PO4, SEM

to observe the morphology of the film, FTIR to detect the presence of hydroxyl group (OH)-

1 and the phosphate group(PO)-3. The results of the characterizations suggested that the

ceramic material maintained its structure unmodified chitosan film.




142

[ BIO-514 ] Mechanical behavior of PCL and PLA blends

used for biomedical applications.

J. Dominguez 2 , G. Martinez 2 , E. Reyes-Alcocer 2 , J. Vazquez-Coello 2 , J.

A. Solís-Ruíz 1 , A. May-Pat 3 , G.M. Alonzo-Medina


1 División de Ingeniería, Universidad Anáhuac-Mayab 2 Emot Ingeniería S.A. de C.V

3 Unidad de materiales, Centro de Investigación Científica de Yucatán, A.C

In the last years, the use of biodegradable polymers have been of great importance in

biomedical field. The biopolymers are widely used in traditional applications, such as

matrices for long-term drug delivery [1-2], short-term fixation devices in the orthopedic field

[2] and surgical sutures [3]. Polylactic acid (PLA) and Polycaprolactone (PCL) are aliphatic

polyesters more used due to their excellent biodegradability, biocompatibility and

bioresorbability [4].

This work is aimed to study of blends of Polylactic acid (PLA) and Polycaprolactone (PCL)

and their mechanical behavior. Five formulations of these blends were proposed (PCL/PLA),

90/10, 85/15, 80/20 and 70/30. The formulations were prepared through

a mixed chamber. The samples were studied by tensile test with a Shimadzu universal testing

machine. In addition the samples were characterized by mean of FTIR and contact

angle technique in order to study the organization of chains of the blends and the wettability

of surface of blends (a way to quantify the hydrophilic behavior of the material)

respectively. The objetive of this study is obtain a polymeric biomaterial, combining the

properties of PLA (high strength and low elongation at break value) and the thermoplastic

behavior of PCL, and that can be used to multiple biomedical applications.

References

[1] Jinhui Zhang, Jia Xu , Hongyan Wang , Weiqun Jin and Junfeng Li Materials Science

and Engineering C 29 (2009) 889–893

[2] J. Heller, J. Control. Release 2 (1985) 167.

[3] B. Jeong, Y.H. Bae, D.S. Lee, S.W. Kim, Nature 388 (1997) 860.

[4] D. Kobayashi, S. Tsubuku, H. Yamanaka, M. Asano, M. Miyajima, M. Yoshida, Drug

Dev. Ind. Pharm. 24 (9) (1998) 819.




143

[ BIO-515 ] Residual Cellulose Films

Karla de lázaro gasca ([email protected]) 2 , Heriberto Hernandez

Cocoletzi ([email protected]) 2 , Eva Águila Almanza 2 , Efrain Rubio

Rosas 1

1 Centro Universitario de Vinculación y Transferencia Tecnológica, Prolongación de la 24

Sur y Av. San claudio, Ciudad Universitaria, Col. San Manuel 2 Facultad de Ingeniería Química, BUAP, Av. San Claudio y 18 sur S/N CU, San Manuel

Edif. 106H

Cellulose is the most abundant organic biomolecule as it forms the most of the Earth's

biomass [1]. It is characterized by its high availability. For example, it contained in the corn

leaf, that most of society is a common waste producing damage to the environment; therefore,

it obliges us to reuse these waste for some benefit of our society. It has now been studied for

creating new materials [2]. In this work the production of cellulose film intended by corn

leaves is performed. Residual leaves are collected, subsequently spraying them with a

conventional coffee mill until pulverization and sift 200 and 250 mesh; after that the samples

were characterized by X-ray diffraction, optical microscopy and infrared spectroscopy. Then,

cellulose films were obtained by using two different particle sizes. For the preparation of the

films was used: Corn leaf spray (0.10 y 0.15 g), glycerol monostearate :( 2 y 3.5 mL), 3.5 mL

of sorbitol, 3.5 mL starch. Each of the materials was added under vigorous stirring and

heating from about 50 ° C for 30 minutes. It was allowed to cool to room temperature then

left in a drying oven for 24 hours at 60 °C. The films were characterized by X-ray diffraction,

Infrared spectroscopy and scanning electron microscopy.

References

[1] Tatsuya H. Glyn O.P., New Fibers (Chapter 8; Cellulosic Fibers), Woodhead Publishing

Limited, Cambridge England, 2da. Ed, 1997, 181-208.

[2] Averous, L., Boquillon, N. (2004) Carbohydrate Polymers, 50, 111

Acknowledgements: This work has been partially supported by VIEP- BUAP.




144

[ BIO-571 ] Optical performance of thermochromic inks

modified with TiO2 nanoparticles

Marcelo Martínez-Puente ([email protected]) 1 , Francisco

Servando Aguirre-Tostado ([email protected]) 1 , Eduardo

Martínez-Guerra 1

1 CIMAV-Monterrey, Alianza Norte 202, Parque PIIT, Apodaca, N.L., México 66628.

Color changing compounds have become increasingly important in recent years in the study

and the production of thermochromics coatings, changing reversibly their color from darker

to lighter tones as temperatures rises. The transition is achieved by a thermally reversible

transformation of the molecular structure of the pigments that produces a spectral change of

visible color. Thermochromic organic inks are being attractive for some industrial

applications however UV degradation is a main problem that must be solved to protect the

optical coating quality. Inorganic UV blockers are usually semiconductor oxides such us

TiO2. TiO2 has good ultraviolet blocking power and is very attractive because of such as

advantages as nontoxicity, chemical stability at high temperature, and permanent stability

under UV exposure. The mechanism of UV-blocking of TiO2 is so far not very clear. Given

the mixed and often conflicting views, it appears desirable for a thorough investigation on

the problem. Coatings have been produced on glass substrates using available organic

thermochromics pigments incorporated into an appropriate binder system to develop a blue

thermochromic ink. In order to examine the behavior of a blue thermochromic pigment two

groups of samples were prepared: the first group consisted of the blue thermochromic

pigment and the binder for different concentrations, and the second comprised of the blue

thermochromic pigment, the binder and titanium dioxide nanoparticles (TiO2 Nps). The aim

of this investigation was to study systematically the influence of different additions of TiO2

nanoparticles as a UV-blocking additive for thermochromic coatings. Thermochromic inks

with nanoparticles were prepared through ultrasonic dispersions and adding them into solvent

with the adequate rheology to be applied by gravity-feed spray gun on glass substrates.

Visible images were taken at different temperatures from 25 °C up to 45 °C to determine the

thermochromic transition (TT) using a stereoscopic microscope equipped with a camera with

a constant aperture of the lens in order to take pictures with the same color and intensity

reference. The glass substrates were heated from ambient temperature to 40 °C taking

pictures with ΔT of 1 °C and processing them by computer taking samples of color in a

specific zone and plotting the RGB coordinates. UV/VIS/NIR spectrophotometer (Varian

Cary 5000) was used for measuring the absorbance spectra of the samples. Coatings without

TiO2 are translucent on glass; meanwhile the presence of TiO2 gives hiding power to the

coating which means that TiO2 Nps give the ability to lighten the surface over the intrinsic

color of blue thermochromic. Thermochromic coatings are presented at their colored phase

for temperatures lower than 30 °C, while their color starts to fade and they are becoming




145

colorless as their temperature overpasses the TT. A slight displacement of TT is observed for

high loads of TiO2 Nps. The absorption spectra were collected for all samples, blue

thermochromic coatings without TiO2 Nps and blue thermochromic coatings with different

additions of TiO2 Nps. Because of its stronger UV absorptance, nanoscale TiO2 exhibits

better UVblocking capacity than that of macroscale TiO2, however, it exerts very little

influence when embedded in thermochromics matrix because of strong scattering

phenomena.

[BIO-572]Obtaining the extracellular matrix of the small

intestine of a rat

J. Reyes-Fernandez1, B. Zenteno-Mateo2, M. López-Fuentes1, M. Portillo-

Sampedroa, M. Cárdenas-García3, J. A. Rivera-Marquez1, M. C. Mendoza-

Herrera1, O. Olivares-Xometl1, Gregorio H. Cocoletzi4

1Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla. Av. San

Claudio y 18 Sur, Edificio FIQ1, C.U., Col. San Manuel, 72570, Puebla, Pue., México. 2Facultad de Ingeniería, Benemérita Universidad Autónoma de Puebla. Boulevard

Valsequillo esquina Av. San Claudio s/n, C.U., Col. San Manuel 72570, Puebla, Pue.,

México. 3Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, 13 Sur 2702, 72410,

Puebla, Pue., México. 4Instituto de Física Benemérita Universidad Autónoma de Puebla. Av. San Claudio y 18

Sur, C.U., Col. San Manuel, 72570, Puebla, Pue., México.

The objective of this study is to obtain a shaped support decellularized three-dimensional

tissue from the intestine of a rat using enzymatic treatments, ionic and nonionic surfactants.

The method of production of an extracellular matrix is described from the intestine of a rat.

Results are presented by observation of stained tissue by optical microscopy to check the

total sample decellularization, IR spectroscopy to discard the presence of trace amounts of

the reagents used and the presence of collagen tissue and scanning electron microscopy to

verify scaffolding structure.

1. Longo, D. L. (2012), Harrison: Principios de Medicina Interna (18ª ed.), México: Mc

Graw-Hill

2. Maghsoudlou, P., Totonelli, G., Loukogeorgakis, S. P., Eaton, S., De Coppi, P. A.

Decellularization Methodology for the Production of a Natural Acellular Intestinal

Matrix. J. Vis. Exp. (80), e50658, doi:10.3791/50658 (2013).

This work has been partially supported by projects VIEP 2015, Mexico.




146

CHARACTERIZATION AND

METROLOGY (CHM)

Chairman:

Roberto Machorro ( CNyN-UNAM)

Sesión Oral

[ CHM-24 ] Thermoluminescence, Raman and

Morphological Studies of Sub-microsized Diamonds

Grown in a Homemade HFCVD Reactor

Rafael Garcia Gutierrez ([email protected]) 3 , Jorge Montes

Gutierrez 2 , Marcelino Barboza Flores 3 , Rodrigo Melendrez Amaviza 3 ,

Oscar Contreras Lopez 1

1 Centro de Nanociencia y Nanotecnología, Universidad Nacional Autónoma de México,

Apdo. Postal 14, C.P. 22800, Ensenada, Baja California, México 2 Departamento de Física, Universidad de Sonora, Apdo. Postal5-088,C.P. 8300,

Hermosillo,Sonora, México 3 Departamento de Investigación en Física, Universidad de Sonora,

Hermosillo,Sonora,Apdo. Postal5-088, C.P. 8300, México

Micro- and nano-diamonds have been studied for their thermoluminiscence properties in

dosimetry field and also due to its no-toxic bio-compatibility diamond has been used recently

in the industry of biosensors.

In this research, a novel and inexpensive method for synthesizing sub-microdiamonds on

silicon is presented. The technique involves Chemical Vapor Deposition using a hot filament

as activator of hydrogen at relative low pressures (~150 Torr). Using a CH4:H2 mixture of

gases, a thermal decomposition was conducted in a horizontal quartz-tube reactor at 2200 °C

filament temperature and 1000 °C substrate temperature, yielding sub-microcrystalline

diamonds.

The micro-diamonds synthetized by this method have a spherical shape and consists of a

mixture of micro- and nano-sized crystallites. The diamonds synthesized in this work showed




147

excellent RAMAN and TL signals. Due to these excellent properties, diamonds obtained by

this technique could be applied as-synthesized in energy and biomedical industry.

[ CHM-41 ] Comparison of microstructural and

mechanical properties behavior of recovering cold work

tool steel molds by GTAW and HVOF welding process

A. Lozano Valle([email protected])1, M. A. Solís Alvarez1 C.

Guevara Chávez2 J. L. Acevedo Dávila2

1861 Steel Solution S. A. de C. V. Calle Paseo de los mirlos 533 Col. Lomas de Lourdes

Saltillo Coahuila C.P. 25090 México. 2Corporación Mexicana de Investigación en Materiales (COMIMSA), Calle ciencia y

tecnología No. 790, Col. Saltillo 400, cp. 25290, Coahuila, México.

This research studies the influence of the processing parameters on the mechanical and

microstructural properties of a Diamalloy 1008 (Fe-Cr-Mo alloy) coating applied with high

velocity oxi-fuel (HVOF) and five different electrodes types were applied by Gas tungsten

Arc Welding (GTAW) on cold work tool steel mold specimens. The aim of these coatings is

commonly used as a protection against corrosion and wear, but they also have the capacity

to recover damaged areas as toolbox for automotive stamp. The specimens were

characterized by optical and scanning electron microscopy to evaluate the quality of the

covering material in the substrate; Vickers microhardness and Pin-ON-Disc were used to

quantify the mechanical performance of the coatings. In the results it was observed a clearly

better performance of the HVOF coating due the absence of fragile microstructure phases

like a martensite and the formation of carbides M23C6 and M6C7.

Key Words: HVOF, GTAW, toolbox, Wear.




148

INVITED TALK

[ CHM-215 ] The satellites in the photoemission spectra

of the 2p core level of transition-metals

Alberto Herrera Herrera-Gomez ([email protected]) 2 ,

Dagoberto Cabrera-German 2 , Gustavo Gomez-Sosa 2 , Jorge-Adalberto

Huerta-Ruelas 1 , Wencel de la Cruz Hernández 3 , Jorge-Alejandro Torres-

Ochoa 2 , Julio Mata-Salazar 2 , Cynthia-Iveth Negrete-Martinez 2 , Gabriela

Molar-Velazquez 2

1 CICATA-Queretaro 2 CINVESTAV-Unidad Queretaro

3 CNyN-UNAM

The shake-up satellites in XPS spectra are due to intrinsic energy losses as the photoelectron

leaves the hosting atom. The first row transition metals, either in the metallic or in the oxide

form (and sometimes in both), display clear shake-up features in the corresponding 2p core

level. They are difficult to quantify because the shape of the main 2p peaks of these elements

are highly asymmetric and the spectra contains a large background contribution. In fact,

there is a frequent correlation between the presence of shake-up satellites and a large

background intensity and, also, a large peak shape asymmetry. Through newly

developed procedures it has been possible to properly fit all these core levels. In addition to

those already described in the literature, the procedures allowed for pinpointing previously

unreported shake-up satellites. A common feature of the satellites is that their spin-orbit

splitting exhibits a remarkable difference with the associated to the main peak, suggesting

angular-dependent correlation effects.




149

[ CHM-224 ] Characterization of luminescent samarium

doped TiO2 nanocomposites synthesized by microwave

using benzyl alcohol route

Ranferi Domínguez Domínguez ([email protected]) 1 , Ranferi

Domínguez Domínguez ([email protected]) 4 , Miguel Ángel

Aguilar Frutis 1 , Gilberto Alarcon Flores 1 , Ciro Falcony 2 , Jorge Luis

González Velázquez 4 , Raúl Iván Sánchez Alarcon 1 , Diego Israel Rivas

López 3 , Héctor Javier Dorantes Rosales 3

1 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Calzada Legaria

No. 694, Miguel Hidalgo, Irrigación, 11500 Ciudad de México, D.F. 2 Centro de Investigación y de Estudios Avanzados, Av. Instituto Politécnico Nacional No.

2508, Colonia San Pedro Zacatenco, CP 07360, Ciudad de México D.F., México. 3 Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Nueva Industrial

Vallejo, Gustavo A. Madero, Ciudad de México, D.F 4 Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Nueva Industrial

Vallejo, Gustavo A. Madero, Ciudad de México, D.F

The structural and luminescent properties of samarium-doped titanium dioxide hybrid

organic-inorganic nanocomposites synthesized by microwave using benzyl alcohol route at

several heat treatment temperatures are reported. These nanocomposites are nanocrystalline

and present a tetragonal (anatase) crystal structure of the titania as determined by x-ray

diffraction.

The photo- and cathodoluminescence characteristics of these nanocomposites were studied

as a function of the synthesis parameters such as heat treatment and samarium concentration.

Excitation with a wavelength of 360 nm resulted in photoluminescent emission peaks located

at 584, 613, 621, 664, 670 and 726 nm, associated with the electronic transitions of the Sm3+

ion. That photoluminescence intensity increased as a function of the treatment temperature

was observed. Also, with increasing doping concentration, a quenching of the

photoluminescence is observed. The chemical composition and surface morphology

characteristics of the nanocomposites are also reported.

The authors acknowledge the financial aid to carry out this work to Secretaría de

Investigación y Posgrado del INSTITUTO POLITECNICO NACIONAL, grant # 2015-

1093.




150

[ CHM-288 ] The Shirley background of the Tougaard

background in the photoemission spectra of transition

metals

Dagoberto Cabrera-German ([email protected]) 1 , Jorge

Alejandro Torres-Ochoa 1 , Gabriela Molar-Velazquez 1 , Gustavo Gómez-

Sosa 1 , Wencel de la Cruz 2 , Alberto Herrera-Gomez


1 CINVESTAV-Unidad Querétaro, Querétaro 76230, México 2 Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México,

Km 107 Carretera Tijuana-Ensenada, Ensenada B.C., México

The 2p core level photoemission spectra of transition metals present a very intense

background contribution that requires an accurate modeling in order to properly use X-ray

photoelectron spectroscopy (XPS) as a quantitative technique.

We obtained and analyzed XPS data of ultra-thin films of Co, Ni, Cu and Zn. Besides the

photoemission lines and the background, the spectra contain satellite peaks and, in some

cases, Auger lines that make the fitting procedure even more difficult.

We used the full Tougaard1 background approach to determine the scattering contribution to

the spectra and subsequently calculated the Shirley background component employing state

of the art algorithms.2

We experimentally determine that the Shirley intensity is larger than the Tougaard

component and that it depends on the chemical state of each chemical specie measured. It

was very interesting to find that an accurate experimental data reproduction is only achieved

by incorporating a Shirley component to the Tougaard background.

1. Tougaard, S. & Sigmund, P. Influence of elastic and inelastic scattering on energy

spectra of electrons emitted from solids. Phys. Rev. B 25, 4452–4466 (1982).

2. Herrera-Gomez, A., Bravo-Sanchez, M., Ceballos-Sanchez, O. & Vazquez-Lepe, M.

O. Practical methods for background subtraction in photoemission spectra. Surf.

Interface Anal. (2014). doi:10.1002/sia.5453




151

INVITED TALK

[ CHM-334 ] Raman scattering and infrared studies of

graphite oxide platelets obtained from bamboo for

electronic applications

Jhon Jairo Prías Barragán ([email protected]) 3 , Jhon Jairo Prías

Barragán ([email protected]) 2 , Katherine Gross 1 , Hernando

Ariza Calderón 3 , Pedro Prieto Pulido 1

1 Center of Excellence for Novel Materials, Universidad del Valle, PO Box 25157, Cali,

Colombia 2 Electronic Instrumentation Technology Program, Universidad del Quindío, PO Box 661,

Armenia, Colombia 3 Interdisciplinary Institute of Sciences, Universidad del Quindío, Carrera 15 Calle 12

Norte, Postal Code 630001, Armenia, Colombia

Graphite oxide is an interesting candidate for electronic applications; therefore, important

efforts are dedicated to both large-scaled and low-cost graphite oxide production as an

intermediate in graphene production. At the same time, research efforts are aimed at

identifying the role of defects in the magneto-electrical properties of platelets for electronic

applications. In this paper, we present a new low-cost fabrication process to obtain graphite

oxide platelets of high crystal and thermo-electrical quality. The graphite oxide platelet

samples were first obtained from bamboo pyroligneous acid (GO-BPA) by thermal

decomposition method using a pyrolysis system for different carbonization temperatures

from 673 to 973 K. The GO-BPA samples were characterized by using Raman, FTIR, XRD,

and SEM techniques, whose results suggest that increased carbonization temperature

increases graphite conversion, boundary defects, desorption of some organic compounds and

phonon response, respectively. Finally, we discuss potential applications of the GO-BPA

samples involving phonon response that would benefit from a fully scaled technology,

advanced electronic sensors and devices




152

[ CHM-349 ] Implementation of the Z-scan technique

using NI cRIO 9074 system

Rubén Gutiérrez Fuentes ([email protected]) 1 , Rubén Gutiérrez

Fuentes ([email protected]) 2 , Miguel Ángel Camacho López 1

1 Laboratorio de Fotomedicina, Biofotónica y Espectroscopia Láser de

Pulsos Ultracortos, Facultad de Medicina, Universidad Autónoma del

Estado de México, Jesús Carranza y Paseo Tollocan s/n, C.P. 50120,

Toluca, México. 2 Universidad Politécnica del Valle de Toluca, Km 5.6 de la Carretera

Toluca-Almoloya de Juárez, Santiaguito Tlalcilalcali, C.P. 50904,

Almoloya de Juárez, México.

In this work we show the implementation of Z-scan technique using NI cRIO 9074 system

to characterize different types of nanofluids and films. This technique was mounted in the

Facultad de Medicina of the Universidad Autonoma del Estado de Mexico. For this, a chassis

NI cRIO9074 of National Instruments, a linear translation stage and a stepper motor

controller BSC203, both of Thorlabs were used. Three steps were followed for the

implementation of Z-scan technique. First, the connection between NI cRIO9074 and

BSC203 controller was made. This connection went through of TTL trigger signals (5 volts).

Second, it was the construction of algorithm and program on LabVIEW. Finally, the

implementation of all optic part of the z-scan technique was made. This implementation can

be used to characterize relatively thin (< 5mm) optical materials. The system testing was

done with gold nanoparticles and a radiochromic film. The results show the nonlinear optical

properties of these samples. The main advantages of using this system is the precision and

spent minor time on measurements.




153

[ CHM-350 ] EFECT OF GEOMETRIC FACTORS IN

DIFFERENTIAL CROSS SECTION

Julio Heriberto Mata Salazar ([email protected]) 1 , Alberto Herrera

Gómez ([email protected]) 1

1 Cinvestav, Unidad Querétaro.

One of the main applications of X-ray photoelectron spectroscopy (XPS) is the assessment

of the chemical composition of surfaces. In a previous work we discussed the inconsistencies,

well beyond the experimental error, that take place when X-ray sources at different angles

are employed [1]. That is, the surface composition assessed employing different sources are

not consistent with each other. These inconsistencies might be due to a number of issues.

We explored 1) the effect of the geometry of X-ray monochromator crystals on the effective

differential cross sections, 2) the combined effect of the partial polarization caused by the

monochromator [2] with elastic scattering on the effective attenuation length (EAL), and 3)

the detailed dependence of the EAL with depth [2]. We concluded that these effect are well

below the uncertainty on the peak intensities and that cannot explain the differences. Other

options are being explored.

Keywords: xps composition calculations, monochromatizer crystal geometry, electron

effective attenuation length.

References:

[1] J.H. Mata-Salazar, A. Herrera-Gómez, “Angular dependence of photoelectric differential

Cross Section”, VI International Conference on Surfaces, Materials and Vacuum (2013).

[2] A. Herrera-Gomez, “Effect of monochromator X-ray Bragg reflection on photoelectric

cross section”, Journal of Electron Spectroscopy and Related Phenomena 182 (2010) 81–83

[3] C.J. Powell, A. Jablonski, “Electron effective attenuation length for applications in Auger

electronspectroscopy and x-ray photoelectron spectroscopy”, Surf. Interface Anal. 2002, Vol

33:211-229.




154

[ CHM-363 ] A pilot comparison in México. -

Determination of mass fraction of four copper gold alloys

with EDS and WDS surface analysis techniques-.

José Manuel Juárez García ([email protected]) 1 , José Antonio Salas

Téllez 1 , Yoshito Mitani Nakanishi 1 , Hugo Rojas Chávez 3 , José Gerardo

Cabañas Moreno 2

1 Centro Nacional de Metrología 2 Centro de Investigación y de Estudios Avanzados del IPN

3 Instituto Tecnológico de Tláhuac II

Has been performed a pilot comparison, having the national metrology center Mexico as

organizer, the objective to compare fraction mass measurements with energy dispersive

spectrometer (EDS) and wavelength dispersive spectrometer (WDS) for binary metal alloys

containing copper and gold, the high energy Cu-K and Au-L lines at about 8 keV and 10 keV,

respectively, were used for quantification. The pure copper and gold reference standards were

also supplied to all participants in the pilot study. In this pilot comparison involved seventeen

different microscopes with the techniques mentioned.

The results will allow participating laboratories to know their measurement capabilities and

the state of its accuracy, so they can take action to which in each case can improvement or

refinement, also they may have information and knowledge to participate in a key

comparison, which will be organized soon.




155

[ CHM-414 ] Measurement technique to characterize a

MOS photoelectric converter

José Guillermo Pérez Luna ([email protected]) 1 , Luis Armando

Moreno Coria 1 , Salvador Alcántara Iniesta 2 , Antonio Esteban Jiménez

González 3 , Joaquín Alvarado Pulido 2

1 Facultad de Ciencias de la Electrónica, Benemérita Universidad Autónoma de Puebla,

Av. 14 sur y Av. Sn Claudio, Ciudad Universitaria, Puebla, Pue., México, CP 72560 2 Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. 14 sur y Av. Sn

Claudio, Ciudad Universitaria, Puebla, Pue., México, CP 72560 3 Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv.

Xochicalco S/N, Temixco Mor., México, CP 62580

The development of an analog circuit to characterize a MOS photoelectric converter is

presented. A photoelectric converter is a device that transforms light into electrical energy.

The converter is a MOS structure that includes a silicon wafer and an aluminum grill. The

silicon surface is separated from the grill by several concentric SiO2 circles. The silicon

surface is the anode and the grill is the cathode. The grill permits that an external light can

be applied on the silicon surface for electron emission. The measurement circuit is designed

with two differential configuration made with operational amplifiers. This circuit also

includes a voltage source, a load resistor and a capacitor. The load resistor is connected

between the voltage source and the photoelectric converter. A specific capacitor is used as a

second load for current variation. The voltage data for the I-V plot are obtained at the output

of the differential configurations. One is for the current measurement and the other for the

voltage measurement between the electrical leads of the photoelectric converter. The results

show that it is possible to measure small currents (10 nA) between the leads of the

photoelectric converter. A parametric study was made for different light intensities.




156

[ CHM-436 ] The photoemission spectra of fully oxidized

Zn

Gabriela Molar-Velazquez ([email protected]) 2 , Dagoberto

Cabrera-German 2 , Wencel de la Cruz 1 , Gustavo Gomez-Sosa 2 , Julio

Mata-Salazar 2 , Alberto Herrera-Gomez ([email protected]) 2

1 CNyN, UNAM. Ensenada, B.C, Mexico C.P. 22800 2 Materials, CINVESTAV-Unidad Queretaro. Queretaro, Mexico C.P. 76230

Most, if not that all, of the X-ray photoelectron Spectroscopy (XPS) analysis of Zn and ZnO

reported in the literature are qualitative in nature [1,2,3,4,5]. Quantitative studies are mostly

absent due to the difficulties inherent to the analysis of transition metal core levels. We found

that a proper analysis requires the simultaneous treatment of both, 3/2 and ½, branches of the

2p core level. However, the complexity of the background prevents this type of analysis with

the traditional methods. By employing the double-Lorentzian line-shape and the active

background approach, we performed an analysis of the whole Zn 2p core level (both

branches) for the fully oxidized case [6,7,8,9,10,11]. Surface and bulk plasmons were

identified, at 17 and 18.5 eV from the main peak, in accordance with the data already reported

by REELS [5] . The chemical compositions resulted in the stoichiometric expected values of

ZnO.

References:

[1] J.H. Scofield. Hartree-Slater subshell photoionization cross-sections at 1254 and 1487

eV, Journal of Electron Spectroscopy and Related Phenomena, 8 (1976) 129-l 37.

[2] Widder, Knupfer, Knauff and Fink. Plasmon behavior of Zn from electron-energy-loss

spectroscopy. Physical Review B, 1997.

[3] Biesenger, Lao, Gerson and Smart. Resolving surface chemical states in XPS Analysis of

first row transition metals, oxides and hydroxides: Sc, Ti, V, Cu and Zn. Applied Surface

Science.

[4] http://xpssimplified.com/elements/zinc.php

[5] “Plasmon excitation energies in ZnO, CdO and MgO”, Hengehold and Pedrotti; Journal

of applied physics 47, 287, 1976.

[6] A double Lorentzian shape for asymmetric photoelectron peaks. A. Herrera-Gomez.

Internal Report. Cinvestav-Querétaro (2011).

http://www.qro.cinvestav.mx/~aherrera/reportesInternos/doubleLorentzian.pdf

[7] A. Herrera-Gomez M. Bravo-Sanchez O. Ceballos-Sanchez and M.O. Vazquez-Lepe.

Practical Methods for Background Subtraction in Photoemission Spectra, Surface and

Interface Analysis (on press)




157

[8] A. Herrera-Gomez, M. Bravo-Sanchez, F.S. Aguirre-Tostado, M.O. Vazquez-Lepe. The

slope-background for the near-peak regimen of photo emission spectra, Journal of Electron

Spectroscopy and Related Phenomena 189 (2013) 76– 80.

[9] Alberto Herrera-Gomez. The active background method in XPS data peak fitting, Internal

Report (Created: 3/2011. Last Update: 9/2012). CINVESTAV- Queretaro.

[10] Alberto Herrera-Gomez. The Peak-Shirley Background (Shirley background in

overlapping peaks), Internal Report (Created: 8/2011. Last Update: 2/2012), CINVESTAV-

Queretaro.

[11] M. Bravo Sanchez, M.O. Vazquez-Lepe, F. Espinosa-Magaña, A. Herrera-Gomez.

Analysis of the Fe 2p spectrum employing the double Lorentzian asymmetric line-shape

(submitted).

[12] http://rdataa.com/aanalyzer/aanaHome.htm

[ CHM-447 ] The photoemission spectra of metallic

yttrium and its oxide.

Víctor Arellano-Arreola ([email protected]) 1 , Gustavo Gómez-

Sosa 1 , Zeus Montiel-González 1 , Alberto Herrera-Gómez


1 CINVESTAV Unidad Queretaro, Queretaro-76230, Mexico

The traditional methods for peak-fitting X-ray photoelectron spectroscopy (XPS) data of

transition metals and their oxides are clearly insufficient. The current methods cannot

reproduce the complex plasmon losses, shake-up peaks, and, most importantly, high peak-

asymmetry present in those spectra. By employing state-of-the-art analysis methods it was

possible properly fit the 3d spectra of metallic yttrium and a small amount of native oxide.

Sublimation of metallic yttrium on Si (100) wafers was performed under vacuum. The angle-

resolved high resolution measurements were carried out employing a non-monochromatic Al

(1486.7 eV) X-ray source and a hemispherical spectrometer with seven channeltrons. The

base pressure of analysis chamber was 10−9 Torr during data acquisition. Peak fitting was

performed using AAnalyzer®1 software, employing symmetric (Voigt) and asymmetric

(double-Lorentzian2) line-shapes. In addition, a combination of Shirley–Proctor–Sherwood

and slope backgrounds were employed using the active approach3.




158

The double-Lorentzian asymmetry factor of the Y 3d peak is 3.33 for both the metallic and

oxide cases. The Y 3d5/2 component is located at a binding energy of 154.58 eV for the metal

and at 157.31 eV for the native oxide. The composition was calculated employing the

Multilayer Model, resulting in close agreement with the expected values of Y2O3.This is the

first report known to the authors that addresses the composition of yttrium oxide from XPS

data.

References

[1]http://www.rdataa.com/aanalyzer/aanaHome.htm.

[2] A. Herrera-Gomez, A double Lorentzian shape for asymmetric photo-electron peaks,

Internal Report, Cinvestav-Querétaro, 2011.

http://www.qro.cinvestav.mx/∼aherrera/reportesInternos/doubleLorentzian.pdf

[3] A. Herrera-Gomez, M. Bravo-Sanchez, F.S. Aguirre-Tostado, M.O.Vazquez-Lepe, J.

Electron. Spectrosc. Relat. Phenom. 189 (2013) 76–80.




159

[ CHM-486 ] Study of the microstructural behavior of

vanadium pentoxide modified with silver

C. Rivera Rodríguez ([email protected]) 2 , F. Gonzalez-Zavala 3 ,

L. Escobar-Alarcón 3 , D. A. Solís-Casados 1 , E. Haro Poniatowski 4

1 Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera

Toluca-Atlacomulco Km 14.5, Unidad San Cayetano, Toluca, Estado de México, 50200,

México. 2 Departamento de Estudios del Ambiente, Instituto Nacional de Investigaciones Nucleares,

Apdo. Postal 18-1027, México DF 11801, México. 3 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal

18-1027, México DF 11801, México. 4 Departamento de Física. Universidad Autónoma Metropolitana Iztapalapa. San Rafael

Atlixco No. 186, Col. Vicentina, Iztapalapa, 09340, México.

Due to their different oxidation states, from V2+ to V5+, Vanadium form a broad variety of

impressive structural arrangements as a result of its coordination with oxygen, which

provides exceptional physical and chemical surface properties, such as: high thermal stability

and high mechanical strength, so it is required in selective oxidation-reduction processes, in

the manufacture of certain important chemicals and mainly in reducing environmental

pollutants. This work shows results about the structural modifications of V2O5 through the

incorporation of different amounts of silver.

The synthesis procedure is performed of direct form by combining vanadium pentoxide with

silver nitrate (NHAg) powdered; the obtained mixtures were subsequently thermally treated

at 500°C during one hour in normal atmosphere. Through measurements carried out by EDS,

the obtained materials showed a gradual increase in silver content ranging from 3.6 to 26.8

at. %, while the vanadium present in the mixtures decreases from 37.6 to 7.2 at. %. Studies

through XRD and Raman spectroscopy reveal that silver is incorporated into the structure of

V2O5 resulting different crystalline phases, Ag0.4V2O5, Ag1.2(V3O8), Ag0.4V2O5, AgVO3,

Ag(VO3), reaching the composition of Ag4V2O7, with certain amounts of V2O9 and

segregates in the form of silver oxide (AgO) and pure Ag. The obtained compounds could

have potential applications as photocatalysis in the degradation of organic compounds

dissolved in waste waters.




160

[ CHM-546 ] Analysis of the Formation of Iron Oxides on

Surfaces of Gray Iron Cast Applying Diffuse Reflectance

Spectroscopy

Catalina Melo Piquive ([email protected]) 1 , Oscar Edwin Piamba

Tulcan 1

1 Universidad Nacional de Colombia

The gray iron cast surfaces are submitted to a high index of corrosion in the exposition with

different environmental substances due mainly to the formation of iron oxides such as

goethite, hematite, maghemite, and lepidocrocite, causing a deterioration in the mechanical

properties of these materials. The characterization of corrosion products on surfaces of

materials that are expose to different conditions of operation, demand the development of a

technique inexpensive, fast and portable. This work describes the optical reflectance

technique that has been developed to the study of this corrosion products. Specially, this

technique will allow the identification of the presence of iron oxides in situ, is a fast and

inexpensive tool and environmentally friendly procedure that could be an alternative to the

conventional surfaces

analysis method. The diffuse reflectance spectrum in the visible and infrared regions

(Vis/NIR, 400-2500nm) were recorded and studied to assess the spectral dependence of these

oxides, predict their relationship and thereby identify it. The agreement with the experimental

results show that the diffuse reflectance spectroscopy could be a helpful method of

quantifying of iron oxides on surfaces.




161

Sesión Poster

[ CHM-11 ] Determination of the Parameters of the

Bergman´s Model for Diabetic Mice Treated with

Ibervillea sonorae

Agustín Ignacio Cabrera Llanos ([email protected]) 1 , Artemio

Alejandro Sotelo de Ávila 1 , Omar Itzamna Rico Ascensión 1 , Emmanuel

Sánchez Velarde 1 , María Guadalupe Ramírez Sotelo 1 , Rodrigo Sánchez

González 1

1 UPIBI-IPN

In this paper the estimation of model parameters Bergman for glucose-insulin interaction in

three states is presented. Besides glucose dynamics in diabetic mice treated with Ibervillea

sonorae extracts in a range of 100-400 mg / kg. Likewise, the estimate is shown for healthy

mice and different parameter values obtained are compared showing how these influence the

dynamics of Bergman´s model. Evolution and variability of the estimate is shown in

graphical form, also, the estimation error is quantified by curves of a quadratic performance

index. The results indicate that the estimated level was reached.

[ CHM-12 ] Portable Measuring System Performance in

Athletic Aerobic Phase Synchronization Visual Platform

with LabVIEW and ATmega Controllers

Emmanuel Sánchez Velarde ([email protected]) 1 , Agustín

Ignacio Cabrera Llanos ([email protected]) 1 , Omar Itzamna Rico

Ascensión 1 , María Guadalupe Ramirez Sotelo 1 , Artemio Alejandro Sotelo

de Ávila 1

1 UPIBI-IPN

In this work, a remote monitoring system for measuring heart rate and deployment of an ECG

signal is presented. This system uses a pulse sensor plug-and-play type placed on the lobe of

the patient to obtain a signal, which is represented by squares; each symmetric pulse width




162

is the width of the plethysmographic signal obtained by the sensor. And, an

electrocardiograph developed for obtaining a derivative (positive, negative, and reference

electrode), a filtering step to obtain the complete signal through the basic vector comprising

Eithoven triangle. Both signals were transmitted via a ZigBee protocol radio frequency, using

two Xbee modules series S1, data were received through a ATMEGA328P, later, by the

LabVIEW platform, and anthropometric data of the individual, to monitor the heart rate,

continued deployment of the 2 signals obtained presented along a routine of aerobic exercise

and a history of heart and indicator signal obtained this in order to observe their status. A

series of measurements of heart rate and ECG signal for individuals undergoing physical

activity of different intensity is presented.

[ CHM-167 ] Spectroscopic analysis of Er 3+ ion doped

sodium chloride crystals

Daniel Enrique Huerta Figueroa ([email protected]) 1 , Rebeca

Sosa Fonseca 2

1 Physics Departement Universidad Autónoma Metropolitana- Iztapalapa, Distrito Federal,

México PO BOX 55-532 2 Physics Departement Universidad Autónoma Metropolitana- Iztapalapa, Distrito Federal,

México PO BOX 55-532.

Photoluminescence analysis of trivalent erbium ion introduced in NaCl monocrystalline, are

presented. NaCl crystals doped with low concentrations of Er3+ ions were grow by Bridgman

technique with molar per cent concentrations of 0.005%, 0.05%, 1% and 2%, respectively.

Measurements of absorption, emission and excitation spectra of as grown NaCl: Er3+ crystals

were made at room temperature, respectively. The optical response of the lower

concentrations sample is so weak, but the 1% mol sample was the best. Any case it was

possible identify the typical transitions of erbium ion from the base state 4I15/2 to several

multiplets due to 4fN configurations. X-Ray pattern show a crystal structure in all the samples.




163

[ CHM-175 ] Design and construction a four-point

method system for electrical characterization of thin

films with photovoltaic applications

Julio César Estrella Rodríguez ([email protected]) 1 , Fabio Chalé Lara 1 ,

Felipe Caballero Briones 1 , González Prieto Dalia Itzel 2 , Óscar Márquez

González 2 , Allan Herrera Eusebio 2

1 Instituto Politécnico Nacional, Laboratorio de Materiales Fotovoltaicos, CICATA

Altamira, Km 14,5 Carretera Tampico-Puerto Industrial Altamira, Altamira, México 2 Universidad Tecnológica de Altamira, Blvd. de los Ríos Km. 3+100, Puerto Industrial,

89603 Altamira, Tamaulipas

We present a system for measuring the sheet resistance by the four point method in

semiconductor thin films. The system includes: a sample holder, a head holder probes, two

electrometers Keithley Model 6517B of high impedance, a current source Keithley 6221 and

a multimeter Keithley model 2000, all connected to a computer through a GPIB interface.For

calculating the sheet resistance of thin films, the Van Der Pauw method was used. Electrical

measurements were performed in darkness and light. As a light source of a halogen lamp 50

watts and a wavelength ranging from 300 to 800 nanometers it is used.The measurement

involves placing the sample in the sample holder, placed above the tip holder and verify that

the tips are in contact with the thin film, the computer program in a sweep current supplied

by the power amperage through two points which fence in the ranges for the deposited

semiconductor material and obtain a voltage at one end of each electrometer finally

measuring the potential difference between both the voltmeter and registering in a database

on the computer.IV curves were performed for CdS:Mg and ZnO:Al thin films. Chemical

Bath Deposition and Spray Pyrolysis methods were employed to deposit thin films on glass

substrates. The behavior of metal and semiconductor junction is present in all thin films, and

there is a growing exponential increase in the measured voltage for current applied. For

CdS:Mg thin films values of sheet resistance was observed that the tendency of resistance

decreasing between 1 GΩ to 100 MΩ applying light on thin films. Resistance in ZnO:Al

films was in 1 to 5 MΩ.

This work is supported by SIP-IPN 20150599 project.




164

[ CHM-187 ] Photoluminescence and EDS studies of

Er3+ ions incorporated in a SiO2 matrix by sol-gel

method

M. Gómez-Miranda ([email protected]) 1 , C. Velásquez

Ordoñez 2 , R. Sosa Fonseca 1

1 Physics Department Universidad Autónoma Metropolitana. Iztapalapa.

PO Box 55-532. México, D.F. 2 Research Center of Nanoscience and Nanotechnology at Universidad de

Guadalajara Centro Universitario de los Valles. Ameca Jal. México

Transparent gels of SiO2 :Er3+ were synthesized and homogeneous sample was obtained by

sol-gel method. Absorption, emission spectra and EDS characterized the final monolith. By

spectroscopic measurements it was possible identify the typical transitions of erbium ion

from the base state 4I15/2 to several multiplets due to 4fn configurations, namely 2H9/2 → 4I15/2, 4F5/2 →4I15/2, 4S3/2 → 4I15/2, 2P3/2 → 4F9/2, 2H9/2 → 4I11/2, 2P3/2 → 4S3/2. Some quantities

were obtained from absorption and emission spectra to make the diagram level of Er3+ ion in

SiO2 matrix. It is adjusted the absorption spectrum data with a deconvolution method in

Gaussian bands to find the areas under the curve, for a qualitative analysis of the relative

intensities each transition. EDS results give information about the homogeneity and the

composition of SiO2:Er3+. The emission spectra show several transitions of Er3+, particularly

the 516 nm that is a reabsorption band and that means that there is an optical interaction

between the ion-host. In this sense, trivalent erbium ion is used as activator in the host lattice

to improve the phosphorescence intensity.




165

[ CHM-219 ] Synthesis of Tm3+:Y2O3 phosphors using

benzyl alcohol route by microwave-assisted technique

Jose Antonio Luna Guzman ([email protected]) 1 , Gilberto

Alarcon Flores 1 , Miguel Angel Aguilar Frutis 1 , Martha Patricia Campos

Arias 1 , Salvador Carmona Tellez 2 , Ciro Falcony 2 , Manuel Garcia

Hipolito 3 , Raul Ivan Sanchez Alarcon 1

1 Departamento de Fisico Quimica, Centro de Investigación en Ciencia Aplicada y

Tecnología Avanzada del Instituto Politécnico Nacional, Legaría 694. Colonia Irrigación,

11500 México DF 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco,

Delegación Gustavo A. Madero CP 0736, México D.F. 3 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,

Del. Coyoacán, CP 04150 México DF.

In this work we present results about the synthesis and characterization of Tm3+:Y2O3

phosphors prepared by the Microwave-Assisted route, usingbenzyl alcohol. The Microwave-

Assisted technique is able to allow a rapid heating to reach the required temperature of

synthesis and it has the advantage to probe the pressure during the reaction. These features

makes the Microwave assisted technique a very controllable, reproducible and potential

method to synthesize different materials and nanomaterials. In this research, Tm3+:Y2O3-

benzoate hybrid organic–inorganic nanocomposites were obtained at 270 °C. The

nanophosphors as synthesized showed an emission band between 420 nm and 500 nm. In

that spectra the most intense peaks were located at wavelengths of 455 nm, which belong to

the 1D2→3F4 transition of trivalent Thulium, as well as a complete structural

characterization by Electron Microscopy, X-ray Diffraction, and Energy Dispersive

Spectroscopy (EDS).


Investigación y Posgradodel INSTITUTO POLITECNICO NACIONAL, grant # 2015

1155 and 2015-1093 and BEIFI-IPN Program.




166

[ CHM-237 ] Study of the optical properties of porous

silicon with different processes

Maricela Meneses Meneses ([email protected]) 1 , José Alberto

Luna López ([email protected]) 1 , Estela Gómez Barojas 1 , José

Francisco Flores Gracia 1 , David Hernández de la Luz 1 , Miguel Ángel

Domínguez Jiménez 1

1 CIDS-IC, BUAP. Edf. 103-C, C.U. Puebla, Pue. 72000, Mexico.

Porous silicon (PS) shows interesting optical and electrical properties that can be used in devices such

as: photodetectors, gas sensors, biosensors, solar cells among others; but is necessary to stabilize the

PS to be compatible with the crystalline silicon (c-Si) technology. The objective of this work is to

study the influence of the thickness of the PS layers after the application of several processes such as

dry oxidation (DO), thermal treatment (TT) and infiltration with organic molecules (FO), specifically

sodium fluorescein. PS single layers were obtained by electrochemical etching of silicon wafers p-

type with orientation (100) and a resistivity 0.01-0.02 Ω•cm, in an electrochemical cell with two

electrodes. The electrolyte solution contains: Ethanol: HF: glycerol, anodization solution was kept

constant for all processes. The current density was of J = 22 mA/cm2, anodizing times were: 30, 60,

120, 240 and 1200 s. Process such as TT and/or DO and/or FO with sodium fluorescein at a

concentration of 2.4 mM were applied a these PS single layers for comparison . The percentage of

porosity (% P) of the first set of PS single layers was realized by the gravimetric technique and the

refractive index (n) was calculated by using the effective medium approximation with the

Bruggeman´s formula. The optical properties of all PS-layers series were characterized after each

process using the spectroscopy techniques: UV-Vis-NIR, fluorescence and μ-Raman. The thicknesses

(0.25, 0.50, 1, 2 and 10 µm) of the single layers for the first PS set were measured with a profilometer.

The fluorescence of PS single layers with TT, DO and FO increases related with the PS single layers

without any process, and there is a shift to lower wavelengths. The reflectance percentage of

PS single layers with TT, DO and FO decreases and Raman spectra show a small peak broadening

with the same position for the c-Si.

Keywords: PS, FS, electrochemical anodization, fluorescence, reflectance.

ACKNOWLEDGMENT

This work has been partially supported by projects CONACyT-154725, PROFOCIE and VIEP-

LULJ-EXC15-G. The authors acknowledge IFUAP, INAOE and CIDS laboratory for their help in

the samples measurements.

email: [email protected]

Referencias:

[1] L. Pavesi. Revista del Nuovo Cimento. 20, 10(1997), 1-20.

[2] M.A. Lambert, Rep. Prog. Phys. 27(1964), 329.





167

[ CHM-243 ] Micromorphology and evaluating

mechanical properties of the dentin-resin interface of

fluorotic teeth conditioning with different bonding

techniques

Ana Josefina Monjarás Ávila 1 , Norma Verónica Zavala Alonso 1 , Gabriel

Alejandro Martínez Castañón 1 , Nuria Patiño Marín 1 , Facundo Ruíz 2

1 Doctorado en Ciencias Odontológicas, Facultad de Estomatología, UASLP, Av. Dr.

Manuel Nava No. 2, Zona Universitaria, San Luis Potosí, S.L.P., México, C.P. 78290 2 Doctorado en Ciencias, Facultad de Ciencias

Introduction: In response to the effects of fluorosis in the enamel, dentin shows

hypermineralization. Because of this and the composition of dentin, adhesive restorations

retention difficult. Recurrent caries in teeth restoration is the main reason for failure.

Antibacterial agents uncured adhesive systems, can flow in the dentinal tubules and remove

residual bacteria in the tooth cavity, particularly beneficial in the formation of marginal

microintervals. Objective: To evaluate the micromorphology and mechanical properties of

the dentin-resin interface of fluorotic teeth conditioning with different bonding techniques.

Materials and Methods: After dental organs extracted by periodontal disease, healthy and

with different degrees of fluorosis, classified according to Dean index were obtained. Bond

strength to dentin-resin interface of fluorotic teeth was evaluated by testing microtensile in

Universal Testing Machine, applying the conventional technique using an etching system

(OptiBond Versa) Deproteinization (5.25% NaOCl for 1 min. ) and silver nanoparticles

(NaAg) and then the resin (Filtek Z250 3M) was placed, photocuring 20 seconds in

increments of 2mm, subsequently the failure mode (adhesive, cohesive, mixed) through the

stereomicroscope was observed, and the resin-dentin interface of fluorotic teeth through

Scanning Electron Microscope each study group analyzed the different bonding techniques.

Averages, standard deviations and ranges of quantitative variables were calculated. Results:

The adhesion in the group of healthy dentin and dentin with mild fluorosis is benefited with

conventional adhesion technique unlike the group with moderate fluorois dentin, where the

adhesion strength is benefit when was applied deproteinisation technique and NaAg.

Adhesive failure was the most presented, followed by cohesive failure. In the

microphotographs continuous dentin-resin interface was observed with the three bonding

techniques in all study groups. Conclusion: Were obtained adhesives satisfactory results in

the three study groups, microscopic signs of the interface, suggesting that the chemical bond

with hydroxyapatite crystals remaining in the partially demineralized smear layer, may have

a role in the binding mechanism of these adhesives of last generation.




168

[ CHM-251 ] Intermetallic phases of Fe-Al formed in the

aluminized steels obtained by hot dip technique

Bárbara Hernández-Hidalgo 1 , Cesar Castelán-Acevedo 1 , Bertha S.

Zalazar-Ramírez ([email protected]) 1 , Roberto T. Hernández L.


1 Departamento de Materiales, UAM-Azcapotzalco, Av. San Pablo 180, Reynosa-

Tamaulipas, Azcapotzalco, México D.F., C.P. 02200

In various steel applications in corrosive environments, process or treatments are required to

reduce or inhibit spoilage. For this purpose, surface layers composed of metals and other

materials are been using, among these the aluminized, obtained by hot dip is employee

intensively. This process involves immersing the metallic specimen in aluminum at

temperatures above its melting temperature. Metals remain in the liquid by certain times. In

this paper, hot dip process are used for obtain a aluminum layer on the steels AISI-SAE 1045,

4140 and 8620. The objective is provides a surface hardness more high, good ductility inside

and good corrosion resistant. Samples of steel bars of varying diameter and 6cm length

slowly immersed in molten Al which is at temperature of 810 ° C and by times of 8 to 40

min of stay. For each steel optic and electronic microscopy photomicrographs are performed.

The images show that depending of the steel and the different stay times, in each samples are

formed two or three regions of phase different between the steel inner and outer layer of Al.

The thickness of the regions depends on the residence time of the steel samples. Studies of

chemical composition (EDS) and X-ray diffraction indicated that each of these regions is

constituted by a single phase intermetallic Fe-Al.




169

[ CHM-258 ] Characterization of intermetallic

compounds in Zn and Zn-18%Cu coatings on the 8620

steel obtained by hot dip

Ivan Caballero-Contreras 1 , Bertha S. Zalazar-Ramírez 1 , Roberto T.

Hernández L. ([email protected]) 1

1 Departamento de Materiales, UAM-Azcapotzalco, Av. San Pablo 180, Reynosa-

Tamaulipas, Azcapotzalco, México D.F., C.P. 02200

The 8620 steel, besides iron and carbon, contains nickel, chromium and molybdenum. Has

high values of surface hardness, good toughness in the core and is corrosion resistant. The

steel is classified as machinery grade. In order to increase these properties it is proposed to

cover it with a Zn coating or a alloy coating of Zn-18%Cu composition both obtained by the

hot dip process. Steel rods of 1inch of diameter and 6cm long, perfectly clean, is slowly

immersed in molten zinc at a temperature of 650 ° C and held within of 10 to 40 minutes.

The surface area characterization by optical and electronic microscopy shows the formation

of two or three layers between Zn and steel depending on the time of stay. Due to immersion

in the alloy, two layers between Zn-18%Cu and the steel are observed. In each case the layers

correspond to intermetallic compounds Zn-Fe for first case and Zn-Cu-Fe in the second.

These layers are result of the diffusion from the surface to steel inwards of the atoms of Zn

and Cu and their chemical reactions with Fe. In order to identify these intermetallic phases,

chemical composition studies (EDS) and X-ray diffraction Microhardness measurements are

made on the obtained surface layer and in each intermetallic area are also presented.

[ CHM-259 ] XPS study of the Ag 3d spectrum

David Salvador García-Zaleta ([email protected]) 1 , Gustavo

Gómez-Sosa 1 , Alberto Herrera-Gómez ([email protected]) 1

1 LPCN, CINVESTAV-U. Querétaro

X-ray photoelectron spectroscopy (XPS) is an important technique to analyze and

characterize the surface of different types of materials such as metals, semiconductors,

polymers, ceramics, etc. However, in many cases the various contributions to the total XPS

signal overlap hiding relevant information. On the other hand, the current methods to analyze

XPS data of transition metals and their oxides are clearly insufficient due to complex plasmon

losses, shake-up peaks, large background intensity and large peak asymmetries. In this work,




170

Ag films were growth on Si (100) wafers using the sublimation method inside a high vacuum

chamber. The films were characterized by the XPS technique. The data was analyzed

considering the branches Ag 3d5/2 and Ag 3d3/2 as well as the (asymmetric) double-Lorentzian

line-shape [1] in order to identify all the possible contributions. The asymmetry of the peak

was measured, including the uncertainty on its value.

References

[1] A. Herrera-Gomez. A double Lorentzian shape for asymmetric photoelectron peaks.

Internal Report. Cinvestav-Querétaro (2011).

http://www.qro.cinvestav.mx/~aherrera/reportesInternos/doubleLorentzian.pdf

[ CHM-265 ] Analysis temperature on the tire tread

Marco Antonio Vázquez Chávez ([email protected]) 1 ,

Marco Antono Cruz Gómez ([email protected]) 1 , Edgar Iram Villagrán

Arrollo 1 , Enrique Buendia Lozada 1

1 Benemérita Universidad Autónoma de Puebla

This research aims to analyze the temperature on the surface of the tire tread in contact with

concrete roadways. The characterization of the tread was made with: SEM, EDS,

nanoindentation, AFM and thermography. The tests were carried out in trucks of public

passenger transport in Puebla México for 12 Km route at average speed of 60 km/h with

detail for ascent and descent of passengers. The results shows that the grooves areas had the

highest temperature in the tread by presenting thermal cracks and loss of rubber elasticity.

Keywords: tire, temperature, tread, thermal cracks




171

[ CHM-268 ] The photoemission spectra of Ru(0) and

Ru(IV) nanoparticles

Gustavo Gomez-Sosa ([email protected]) 2 , Nidia Garcia-Peña 1 ,

Rocio Redon 1 , Mariela Bravo-Sanchez 2 , Alberto Herrera-Gomez


1 CCADET-UNAM 2 CINVESTAV Queretaro

A recent report1 has been published regarding the synthesis of Ru(0) and Ru(IV)

nanoparticles employing low amounts of solvents. We performed X-Ray Photoelectron

Spectroscopy (XPS) analysis to identify oxidation states of these materials. Ru nanoparticle

was prepared by a mechanochemical method consisting of milling RuCl3·nH2O and BH4 in

an agate mortar for 5 min, then washed with an small amount of water and ethanol and dried

into an oven. The powder was compressed against an indium foil and mounted into a sample

holder, all inside a glove box custom-coupled to the XPS load lock chamber. The sample

handling was done under a high purity nitrogen atmosphere, as these nanoparticles react

violently with ambient oxygen. The high resolution measurements were carried out

employing a monochromatic Al K (1486.7 eV) X-ray source and a hemispherical

spectrometer with seven channeltrons. Base pressure of analysis chamber was 10−9 Torr for

data acquisition. Pass energy was 10 eV for high resolution spectra. Peak fitting was

performed using AAnalyzer software, employing a Voigt profile2. The asymmetric peak

corresponds to a double-Lorentzian line-shape3. Also, a combination of Shirley–Proctor–

Sherwood and slope backgrounds were employed using the active approach4.

Since the processing of the nanoparticles was done in the presence of oxygen, it was at

expected that the ruthenium was going to be found in an oxidized state. Surprisingly, the XPS

data clearly showed the presence of only Ru(0), without any detectable Ru2+ or Ru4+. As an

additional test, the nanoparticles were subjected to thermal oxidation, heating at 850 ºC for

20 h in the presence of molecular oxygen to force the presence of oxides.

Two evident contributions were observed, a doublet at 279.11 and 283.40 eV corresponding

to Ru(0), and a second doublet with a binding energy about 1.7 eV higher, which can be

attributed to Ru(IV). This doublet is consistent with the spectra of Ru(IV) nanoparticles

processed by colloidal and solvothermal methods, consisting of large amounts of solvents

under air atmosphere, alternated with washings and drying under vaccum . A detailed

analysis of the Ru(0) and Ru(IV) is presented.

References




172

[1] N.G. Garcia-Peña, R. Redon, A. Herrera-Gomez, A.L. Fernandez-Osorio, M. Bravo-

Sanchez, G. Gómez-Sosa, Solventless synthesis of ruthenium nanoparticles, Applied Surface

Science (2015) 340, 25-34

[2] http://www.rdataa.com/aanalyzer/aanaHome.htm.

[3] A. Herrera-Gomez, A double Lorentzian shape for asymmetric photo-electron peaks,

Internal Report, Cinvestav-Querétaro, 2011.

http://www.qro.cinvestav.mx/∼aherrera/reportesInternos/doubleLorentzian.pdf

[4] A. Herrera-Gomez, M. Bravo-Sanchez, F.S. Aguirre-Tostado, M.O.Vazquez-Lepe, J.

Electron. Spectrosc. Relat. Phenom. 189 (2013) 76–80.

[ CHM-301 ] Effect of process control agent during high-

energy milling: a critical balance between cold welding and fracture

H. Rojas-Chávez ([email protected]) 4 , D.A. Mora-Alvarado

([email protected]) 4 , J.A. Andraca-Adame 2 , M.L. Mondragón-Sánchez 3 , J.M.

Juárez-García 5 , D. Jaramillo-Vigueras 1

1 Centro de Investigación e Innovación Tecnológica - IPN 2 Centro de Nanociencias y Micro y Nanotecnologías - IPN

3 Instituto Tecnológico de Morelia - TecNM 4 Instituto Tecnológico de Tláhuac II - TecNM

5 Laboratorio de Microanálisis - CENAM

In the case of Pb–Sn (ductile–ductile) system, it is difficult to use the high-energy milling

(HEM) technique owing to stress, strain and recovery may occur almost simultaneously

during milling, in other words, an excessive cold welding takes place. In such case, HEM-

process results in agglomeration of the as-milled raw materials, this in turn suppresses the

mechanosynthesis.

The nature of the ductile–ductile system is strictly related to its nature to store energy, as

expected from its ability to generate and annihilate structural defects. During HEM-process

heavy plastic deformation induces a high density of crystalline defects, such as: dislocations,

stacking faults, grain boundaries effects, vacancies, and so on. All these defects enhance

short-range mass transfer (diffusion) between precursors.

Owing to the high volatility of CH3-CH2-OH (C2H6O) near to room temperature, it can

effectively reduce coarsening and agglomeration during HEM-process. As a liquid, ethanol

is embedded and finely distributed among the powders’ surface. However, one should expect

that ethanol works as a solid–liquid reaction to helps in alleviating the tendency of ductile

powder particles towards powder-to-ball/vial cold welding.




173

The Pb–Sn system is susceptible to hydrogen embrittlement. It is expected that the

mechanism of hydrogen embrittlement for Pb–Sn system is that the high energy impacts

(milling media) on the powders’ surface decompose ethanol embedded. As a consequence,

H2 molecule and H atoms are obtained, and then atomic hydrogen diffuses into crystalline

defects induced during HEM-process.

Ethanol, as a process control agent (PCA), is used to achieve the critical balance between

cold welding and fracturing, and enhance the HEM-process efficiency. Thus, a study into the

effect of PCA on solid–liquid, solid–solid and solid–gas reactions ball milling is necessary

and important.

XRD and SEM results indicate that C2H6O as PCA showed anti-adhesive properties during

HEM-process. The particle size, powder output and purity of the product depend on the

properties of the PCA. Moreover, the PCA is not only able to decrease bonding and

agglomeration, but can also accelerate the reaction to some extent.

[ CHM-307 ] Monitoring the kinetics of formation of

aggregates in ionic solutions by light scattering

Oscar Ivan Pérez-San-Martín ([email protected]) 1 , Narcizo

Muñoz-Aguirre ([email protected]) 1

1 Instituto Politécnico Nacional, Sección de Estudios de Posgrado e Investigación, Escuela

Superior de Ingeniería Mecánica y Eléctrica-UA. Av. Granjas, N° 682, Colonia Santa

Catarina. Del. Azcapotzalco, CP. 02250, México, D.F. México

In this work the study the scattering of visible light through ionic solutions is presented. One

of the specific objectives of this study is to measure particles whose size is below of the

micrometer scale. Light transmission spectra as a function of time and using a wavelength

range of 400 to 800 nm were considered. Analysis in pure water and solutions such as salt

water and water polystyrene particles at different temperatures is presented. For taken into

account factors as the solute employed and the temperature at which the measurement is

performed, an experimental set up which facilitate the incorporation of the solution and

adjusting the optical fibers of components measuring a portable spectrometer was designed.

A theoretical model of particle agglomeration based on the Tindall effect is proposed.

References




174

E. López-Sandoval, C. Vázquez-López, B.E. Zendejas-Leal, G. Ramos, E. San Martín-

Martínez, N. Muñoz-Aguirre, and E. Reguera “Calcium carbonate scale inhibition using the

“allotropic cell” device”, Desalination 217, 85-92 (2007).ISSN: 0011-9164.

Work partially supported by Instituto Politécnico Nacional from México with the project

number SIP-20151005.

[ CHM-309 ] Textural and microstructural properties of

SBA-15 for removal of pharmaceuticals from

wastewater.

Martha Chico Vázquez ([email protected]) 1 , Mónica Rosalía

Jaime Fonseca 1 , Patricia Rayo Mayoral 2

1 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada IPN 2 Instituto Mexicano del Petróleo

Recently, pollution of pharmaceuticals in water is an environmental concern. Unknown

chronic ecotoxicities effects together with antibiotic resistance issue are making increasingly

anxieties due to wide spreads of pharmaceuticals. The current technologies used in water

treatment systems are not effective enough to eliminate many pharmaceuticals. Therefore,

treatment technologies that achieve effective pharmaceutical removal need to be developed

[1]. Among several technologies proposed for the removal of pharmaceuticals from water,

for example, nanofiltration, advanced oxidation processes, and adsorption. Adsorption has

been receiving special attention owing to its simplicity, low setup and operation cost, and no

production of undesirable by products. Several studies have evaluated the adsorption of

pharmaceuticals on zeolites, activated carbón, montmorillonite, and mesoporous silica.

Among them, mesoporous silica with high surface area, large and uniform pore size, high

pore volume, and tailorable surface can be good candidates for the adsorptive removal of

pharmaceuticals [2].

In this study, SBA-15 (mesoporous silica), was synthesized using the method reported by

Zhao [3]. Whit this method, a reproducible mesoporous material with a surface area of 745

m2/g, pore size of 8.6 nm, particle size 1.2 m, hexagonal structure with symmetry p6mm

(confirmed by XRD and TEM) was obtained.




175

[ CHM-310 ] Nonlinear Refractive Index Coefficient of

Cadmium Sulfide Nanoparticles Obtained by Z-scan

Technique

Yolanda Elinor Bravo-García ([email protected]) 2 , Patricia

Rodríguez-Fragoso 3 , Edmundo Reynoso-Lara 2 , José Antonio Dávila-

Pintle 2 , José Alberto Andraca-Adame 1 , Gerardo González de la Cruz 3 ,

Julio Gregorio Mendoza-Álvarez 3 , Orlando Zelaya-Angel 3

1 CNMN-IPN 2 FCE-BUAP

3 Physics Department-CINVESTAV

Z-scan technique is a simple method to obtain both refractive and absorption nonlinear

coefficients. It consist in to scan a sample in a focused beam to measure the transmittance to

far field. In the photodetector there is an aperture to detect only on-axis intensity. The data

plotted of transmittance vs position is the so called z-scan curve. There are many models to

reproduce these curves, here we used the photoinduced focal length model (PFL). It considers

to the sample as a lens with a dependence of beam radius powered to integer number m.

Depending of the value of m is the physical phenomenon that determines the nature of the

nonlinear optics property.

Semiconductor nanoparticles CdS with uniform size were prepared using different

passivating agents in aqueous solution with various pH. A cw HeNe laser was used in the

wavelength of 632 nm with different powers. The nanoparticles exhibit both positive and

negative nonlinearities whose amplitude depends on the pH.




176

[ CHM-312 ] Development of a fiber optic Surface

Plasmon Resonance sensor using gold nano-spheroids

Víctor Manuel Canchola-Flores ([email protected]) 1 , Narcizo

Muñoz-Aguirre ([email protected]) 1



Catarina. Del. Azcapotzalco, CP. 02250, México, D.F. México

Surface plasmon resonance sensor which employs gold nano-spheroids deposited on a fiber

optic cross section was developed. For their structural characterization, gold nano-spheroids

were formed from a gold thin film deposited on glass substrates by an electron beam

evaporation system after the thermal treatments at 500, 600 and 700 °C. AFM images showed

longitudinal axes of average sizes of 40 nm to 80 nm in spheroids geometries showing

changes as the annealing temperature increases. The UV-VIS spectra showed surface

plasmon resonances shifts when the fiber optic interacts with a fluid as showing by Fabrice

Meriaudeau et. al. [1] and N. Muñoz-Aguirre et. al. [2] for gold particles supported on glass.

It was also confirmed that the resonances frequency positions depends on the size and shape

of the nano-spheroids.

References:

[1] F. Meriaudeau, A. Wig, A. Passian, T. Downey, M. Buncick, T.L. Ferrell, Gold island

fiber optic sensor for refractive index sensing, Sens. Actuators B 69 (2000) 51–57.

[2] N. Muñoz-Aguirre, A. Passian, L. Martínez Pérez, E. López-Sandoval, C. Vázquez-

López, J. L. Jiménez-Pérez and T.L. Ferrell. The use of the surface plasmons resonance

sensor in the study of the influence of “allotropic” cells on water. Sens. Actuators B 2004,

99, 149-155.

Work partially supported by Instituto Politécnico Nacional from México with the project

number SIP-20151005.




177

[ CHM-339 ] Characterization of amorphous ribbons by

magnetoimpedance tecnique.

Andrés Rosales ([email protected]) 1 , Diego Gómez 1 , Fabio

Saccone 2

1 Universidad Nacional de Colombia Sede Manizales 2 Universidad de Buenos Aires

The study of magnetic and electrical properties of materials has influenced the technological

development of societies. In this context, properties such as impedance, reactance,

susceptance, the quality factor, among others, make these materials be useful to industrial

and medical purposes. Soft magnetic materials that exhibit giant magnetoimpedance MIG,

have been studied intensively. It has been determined its impedance in the magnetic field for

different frequencies, however, other characteristics such as its susceptance and quality factor

have not been studied yet, and those are important parameters that characterize them for their

technological applications. In this work we adapted a system for measuring the above

parameters, which has been applied to study different materials. Also discussed the different

characteristics of the developed system to parameters such as frequency and applied magnetic

field variations in the samples.

[ CHM-343 ] A new satellite found on manganese spectra

Cynthia-Iveth Negrete-Martinez ([email protected]) 1 , Gustavo

Gomez-Sosa 1 , Julio-Heriberto Mata-Salazar 1 , Dagoberto Cabrera-

German 1 , Alberto Herrera-Gomez ([email protected]) 1

1 CINVESTAV -Unidad Querétaro. Queretaro, 76230 Mexico

A shake-up satellite was found in manganese spectra obtained by X-ray photoelectron

spectroscopy. Manganese was evaporated on a Si (001) wafer in a high vacuum chamber

employing a tungsten filament. To discriminate the satellite from an oxide peak, the early

stages of oxidation were studied in detail. The oxidation was carried out at room temperature

with three oxygen exposures (4L, 44L and 400L). The curve fitting of the main peaks (Mn

2p, Mn 3p, Mn 3s, O 1s and C 1s) was done employing the double-Lorentzian assymmetric

line shape [1] and the active background approach [2, 3]. In addition to the novel peak fitting,

which resulted in a close reproduction of the experimental data, the analysis revealed the

presence of a shake-up satellite which has not been reported in literature.




178

Keywords: Shake-up satellite, Double-Lorentzian, Active Background.

Acknowledgements: This work was supported in part by CONACyT Projects INFR-2011-

01 #163219 and CB-2012-01 #179304.

[1] A double Lorentzian shape for asymmetric photoelectron peaks. A. Herrera- Gomez.

Internal Report. Cinvestav-Queretaro (2011).

http:// www.qro.cinvestav.mx/ ~aherrera/ reportesInternos/ doubleLorentzian.pdf

[2] “Practical Methods for Background Subtraction in Photoemission Spectra.” A. Herrera-

Gomez, M. Bravo-Sanchez, O. Ceballos-Sanchez, and M.O. Vazquez-Lepe. Surf. Interface

Anal. 2014, 46, 897–905 DOI 10.1002/sia.5453.

[3]“The Slope-Background for the Near-Peak Regimen of Photoemission Spectra.” A.

Herrera-Gomez, M. Bravo-Sanchez, F.S. Aguirre-Tostado, M.O. Vazquez-Lepe. Journal of

Electron Spectroscopy and Related Phenomena 189 (2013) 76-80. (DOI

10.1016/j.elspec.2013.07.006.)

[ CHM-347 ] Optical characterization of materials by

Spectral Correlation technique and Time Resolve

Spectroscopy.

Angel Adalberto Duran Ledezma ([email protected]) 1 , Luis

Fernando Rojas Ochoa ([email protected]) 1 , Miguel Garcia Rocha 2

1 1Depto. de Física, Cinvestav-IPN. Apartado Postal 14-740. México DF

07000. México 2 1Depto. de Física, Cinvestav-IPN. Apartado Postal 14-740. México DF

07000. México E-mail: aadurn@fis.

We present a novel technique to perform the optical characterization of thin films. The

technique of spectral correlation in frequency domain is great tool to obtain the main optical

properties in real time in thin film such as the diffusion coefficient and the absorption length

via of photons scattered in a random turbid medium. We employed the photon diffusion

approximation theory and, using the correlation function fitting, applied the technique to the

characterization of Teflon slabs of different thickness. We compare these results with

measurements performed with Time-resolved Spectroscopy, considering the photon time of

flight and we recovered the results for the spectral correlation.

*This work has been partially supported by Conacyt/Mexico.




179

[ CHM-368 ] Development of an AC and DC current Hall

effect-based measurement system: Application to

magnetic metallic glasses

A. Rosales-Rivera ([email protected]) 2 , J.J. Melo-Quintero 2 , J.P.

López-Tabares 2 , J. Hincapie-Bedoya 2 , H.A. Giraldo-Daza

([email protected]) 2 , H.A. Giraldo-Daza 3 , J.A. Chavarria-Rubio 2 ,

A.A. Velásquez-salazar 2 , D.F. Gómez-Montoya 2 , A.A. Velásquez-salazar 1

1 Departamento de Ingeniería Eléctrica, Electrónica y Computación, Facultad de

Ingeniería y Arquitectura, Universidad Nacional de Colombia, Sede Manizales, Manizales,

Colombia 2 Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y

Naturales, Universidad Nacional de Colombia, Sede Manizales, Manizales, Colombia 3 Universidad de Manizales-Facultad de Ciencias e Ingenieria-GIDIT

In the first part, we describe the design and instrumentation of an AC and DC current Hall

effect-based measurement system. This system consists of a Current Source (Model

6221 DC-AC, Keithley Instruments Inc.) coupled to a Nanovoltmeter (Model 2182A,

Keithley Instruments Inc.) or a Lock-In Amplifier (Model SR 530, Stanford Research

System), and an electromagnet (Phylatex) that provides magnetic fields up to 1 T. This

system has several measurement facilities including Hall voltage, Hall coefficient, resistance,

resistivity, and I-V curves, and can be operated in both DC and AC current modes. The

functioning of this measurement system was verified using both a standard sample of copper

and several resistor circuits that correspond to simulated metallic and semiconductor

samples. In the second part, we use the previous system to study the magneto-transport

properties of several materials at room temperature including Iron- and Cobalt-based metallic

glasses. We present also an analysis of these magneto-transport properties.




180

[ CHM-415 ] Optical and electrical characterization of

surface states effects of AlGaAs/GaAs heterostructures

grown by MBE

Irving Eduardo Cortes Mestizo ([email protected]) 1 , Leticia

Espinosa Vega 1 , Joel Briones 4 , Ravindranath Droopad 3 , Manuel Perez

Caro 3 , Cristo Manuel Yee Rendón 2 , Edgar Briones 1 , Víctor Hugo

Méndez García ([email protected]) 1

1 CIACyT, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78210 SLP, México 2 Facultad de Ciencias Físico–Matemáticas, Universidad Autónoma de Sinaloa, Culiacán,

80000 CLN, México 3 Ingram School of Engineering, Texas State University, San Marcos, TX 78666, USA

4 Instituto de Estudios Superiores de Occidente, Guadalajara, 45604 GDL, México

Surface physics plays an important role in the description of phenomena that are related with

the interruption of the infinite translational symmetry of the idealized crystalline solid. The

surface of a semiconductor is a particularly simple type of interface, at which the solid is in

contact with the surrounding world, nevertheless at nanometric-scale surface-atoms mean an

important percent of the whole device altering their optical and electrical properties. Surface

and interface physics thus have an enormous impact on research and technology of

nanometric devices. In this work, we analyze and measure the effect of surface properties on

two-dimensional electron gas (2DEG)-containing AlGaAs/GaAs heterostructures by

Photoreflectance (PR) and Raman (RE) spectroscopy in conjunction with Hall measurement

(HM). PR exhibits Franz-Keldysh oscillations (FKO) in the region between 1.45 to 1.8 eV

which are depending on the built in surface electric field intensity (ES) and depletion-layer

width. In heterostructures where the doped layers are located far below the surface, ES is in

the range from 5 to 2.5 x107 V/m. Contrariwise, the PR spectra from samples in which the

doping layer is close to the surface, did not exhibit FKO, since the built in depletion-region

(DR) is very short. Values from 9 to 55 nm of DR were found in our set of samples by RE

using the peak amplitude of the longitudinal optical phonons, and the coupled phonon modes

[1]. We determinate that FKO appears only for those samples where DR > 20 nm. High

intensities of ES generate a strong conduction band-bending which, combined with large DR

can avoid the formation of a 2DEG in the case that the 2DEG quantum well falls within the

depletion-zone. HM indicates that samples where the intensity of ES is large exhibit low

carrier concentration and mobility in the 2DEG. This study allows us to determinate the

charge density, electric field at surface and depletion-layer values which can be introduced

to a numerical model in order to understand and avoid the surface-states effects on the carrier

distribution and conduction band profile of the samples [2].




181

[1] X. Chen et al. J. Electrochem. Soc.Vol. 140, issue 7, 2085-2088 (1993).

[2] A. Cisneros-de-la-Rosa et al. J. Vac. Sci. Technol. B 32, 02C110 (2014).

Acknowledgments:

The author acknowledges the financial support of CONACYT, CeMIE-SOL 22,

FRCUASLP, INFR-2015-01: 255489 and PNCPN2014-01: 248071.

[ CHM-458 ] Symmetry analysis in Bi2Fe2Ga2O9 single

crystals

F. P. Reyes-Ixta ([email protected]) 1 , M. C. Muñoz-Ramírez 1 , J.

Ortiz-Saavedra 1 , H. Tototzintle-Huitle 1 , A. Puga 1 , L. Pérez-Arrieta


1 Unidad Académica de Física. Universidad Autónoma de Zacatecas. Calz. Solidaridad

Esq. Paseo La Bufa s/n. C. P. 98060. Zacatecas, Zac.

The Aurivillius phases such as Bi2Ga4O9 and Bi2Fe4O9 changes in the symmetry usually

occur at a defined temperature known as the Curie temperature (TC). The most common

structural change is the tetragonal-orthorhombic and orthorhombic-monoclinic due to the

polarization and the ferroelectric character of these materials. Bi2Fe2Ga2O9 compound can

be obtained from any of the above compounds by half substituting Fe+3 or Ga+ 3 ions or Ga +3 Fe+3 respectively. These compounds exhibit antiferromagnetic properties with

orthorhombic structures and two formulaic units per unit cell (Z = 2). In this work the

symmetry of well constructed single crystal of stoichiometry Bi2Fe2Ga2O9 with monoclinic

habit is studied. Some works had previously reported a habit and crystalline structure of

orthorhombic symmetry (Pbam). In this work, by X-ray diffraction measurements, we

conclude that this material have monoclinic symmetry. The chemical etching process allowed

us to assign the point group 2/m to this compound. By the Raman microscopy analysis got

only 2 different spectra which confirmed that symmetry is monoclinic. In the case of

orthorhombic symmetry 4 different spectra are expected. The number of phonons found is

lower than calculated for 2 formulaic units (Z), but corresponds very well with those

calculated for Z = 1.




182

[ CHM-516 ] Soft magnetic metallic glasses: application

in magnetic field sensors, fluxgates.

Abilo Andrés Velásquez Salazar ([email protected]) 1,2 , Andrés

Rosales Rivera ([email protected]) 2 , Diego Fernando Gómez

Montoya 2 ,

1 Departamento de Eléctrica, Electrónica y Computación, Facultad de

Ingeniería y Arquitectura, Universidad Nacional de Colombia, Sede

Manizales, Manizales, Colombia 2 Laboratorio de Magnetismo y Materiales Avanzados, Facultad de

Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Sede

Manizales, Manizales, Colombia

Soft magnetic amorphous ribbons of Fe73.5−xCrxSi13.5B9Nb3Cu1 family have a wide variety

of sensor applications and because of its high magnetic permeability and high

magnetoimpedance can be used in many magnetic sensors, one of them is fluxgate

magnetometers. This type magnetometer is used to measure very weak magnetic fields such

as those studied in geomagnetism, mineral exploration and space research. Annealing of

these ribbons can improve their magnetic properties due to its nanocrystallization. It has been

demonstrated that chromium changes the electrical and magnetic properties as it replaces the

iron. Furthermore, the universality class of magnetic phase transitions is changing from Ising

to Heisenberg, indicating an increase in the itinerant magnetism. A fluxgate sensor system

was emulated using a wave generator, a oscilloscope and a two coils, one to generate an

alternating magnetic field and the second to pick up the induction produce by a core of a soft

magnetic ribbon of Fe73.5−xCrxSi13.5B9Nb3Cu1 family. Ribbons with 0 to 20% chromium

content, "as cast" and annealed at 520 ° C were used as cores of the coils. Measures of weak

magnetic fields on the order of Earth's magnetic field were performed with each ribbon to

determine how the chromium and annealing influence the behavior of the sensor system.

Keywords: Soft magnetic metallic glasses, Fluxgate, Sensors, Magnetism.




183

[ CHM-560 ] Characterization of the structure of TiO2

P25 modified by mechanosynthesis

Juan Manuel Padilla Flores ([email protected]) 2 , José Ernesto

Domínguez Herrera 2 , Octavio Maldonado Saavedra 2 , Erick Adrian

Juarez Arellano 1 , Enrique Castillo Zaragoza


1 Dpto. Ciencias Quimicas, Universidad del Papaloapan, Av. Universidad S/N 2 Dpto. Nanotecnología, Universidad Tecnológica del Centro de Veracruz, Av. Universidad

No. 350

Structural changes in the modified P25 TiO2 were studied from mechanosynthesis method at

650 rpm at different times in air. These materials were characterized by Raman, XRD and

UV-VIS reflectance. X-rays show changes in the crystallinity of TiO2 as new corresponding

phases appear to deformation generated by the mechanical stress to which it is subjected,

also, decreasing grain size generates a frequency-range which reflected in the widening of

the diffraction peaks, this behavior is further confirmed in the results of Raman spectroscopy

while the spectra of UV-Vis diffuse reflectance, shows that the milling time changes the

electrical conductivity of the material, so that the mechanosynthesis applied on the TiO2 can

modify the properties of electrical conductivity of the material, also, it was determined that

the electrical properties of the material are a function of particle size.




184

MICROELECTRONICS AND MEMS

(MEM)

Chairman: Wilfrido Calleja (INAOE) Horacio Estrada (CENAM)

Sesión Poster

[ MEM-38 ] Taking advantage of distributed parasitics of

aluminum/cooper interconnects for resonant oscillators

implementation

Ana Karen Armenta Márquez 1 , Mónico Linares Aranda

([email protected]) 1 , Luis Hernández Martínez 1

1 Instituto Nacional de Astrofísica, Óptica y Electrónica. Área de Electrónica, Luis Enrique

Erro No. 1, Santa María Tonantzintla, C.P. 72000, Puebla, México.

Currently, have emerged several demands (like reliability, speed, signal integrity, power

consumption, among others) in the transfer of signals between the different devices that

compose the Metal-Oxide-Semiconductor Integrated Circuits (MOS-IC) made on silicon

substrate. The generation and distribution of high quality periodic signals where the

characteristics of high frequency, low skew and jitter, low power consumption, among others

are required in the signal (clock) that serve to synchronize efficiently complex systems, such

as microprocessors, and communication systems are every time more tight.

In order to partially address these demands, the technologies of MOS-IC have incorporated

in their manufacturing process a greater number of interconnection levels made of aluminum

and more recently of copper, in conjunction with the use of new insulating materials such as

low-k dielectrics that are used to separate the different levels of metal. All this has given rise

to the increment of parasitic resistance, capacitance and inductance between the different

metal levels due to vias used to connect them and the design of the interconnection lines and

their layout, as well as to changes in the manufacturing process.

In this work, resonant ring oscillators based on the inductive and capacitive distributed

parasitics from on-chip wiring are presented. The configuration used in these oscillators is a

single pair of closely spaced rings, implemented on higher metal layer on a MOS-IC. At one

end, these rings are connected in a Mobius fashion, and carefully selecting the perimeter of




185

the ring, wire width and spacing, the values of the inductive and capacitive distributed

parasitics are such that the ring exhibits extremely high frequency oscillations. In these types

of resonant oscillators, charge is recirculated, and therefore these oscillators are highly

energy-efficient. The parasitic inductance and capacitance of the rings are fixed once the ring

perimeter; wire dimensions, layer and spacing are determined. The oscillation frequency of

the resonant oscillators is determined by the total parasitic inductance and capacitance values.

The resonant oscillators are implemented using a UMC 180 nm Mixed-Mode, Single-Poly

6-Metal (1P6M), P-Substrate, RFCMOS Technology.

[ MEM-79 ] Transport N-S-N, F-S-F characterization for

the superconductors Nd[Fe, Co]AsO

Ariam Mora-Hernández ([email protected]) 1 , Agustín Conde-

Gallardo 1

1 Departamento de Física, CINVESTAV

Metal organic chemical vapor deposition technique (MOCVD) and arsenic diffusion

processes have been used for synthesis of Nd[Fe, Co]AsO polycrystalline films. The X-ray

diffraction and energy dispersive X-ray microanalysis (EDX) indicate that the films have the

structure and composition necessary for a superconducting transition at ~15K. The behavior

of the electrical resistance confirms this superconducting transition. By using

Photolithography technique we create a 2 microns thick line of Nd[Fe, Co]AsO

superconductor material and evaporate Au or Fe electrodes on it, to form normal-

superconducting-normal (SNS) or Ferromagnetic-Superconducting-Ferromagnetic (FSF)

junctions. With these junctions we measure current-voltage curves both above and below Tc,

to see the response of the electron tunneling to normal and magnetic electrodes. Additionally,

we try to measure differential conductance to measure the superconducting gap in this

material which has not been stablished before.




186

[ MEM-151 ] Electrical characteristics of capacitors

made of high-K dielectrics based on Ti(X)Al(1-X)O(Y)

thin films

Norberto Hernandez-Como ([email protected]) 2 , Francisco

Hernandez-Cuevas ([email protected]) 2 , Jacobo Munguia 2 , Salvador

Mendoza 1 , Miguel Aleman 2 , Marco Ramirez-Salinas 1

1 Centro de Investigación en Computación, Instituto Politécnico Nacional, México. 2 Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional,

México

Dielectric materials exhibiting high dielectric constants play critical roles in a wide range of

applications including RF MEMS switches, high-sensitivity capacitive pressure sensors and

energy-storage capacitors for piezoelectric energy harvesters. In this work, DC reactive

sputtering, using metallic targets (Al and Ti) and oxygen/argon plasma, is used to grow oxide

films at 100 oC. A dielectric constant (k) over 20 can be achieved in nanolaminate structures

by alternatively depositing nanometric layers of aluminum oxide (Al2O3) and titanium oxide

(TiO2) films. We have particular interest in the Ti(x)Al(1-x)O(y) (TAO) films because it

combines a high-k material (TiO2 with a k>50) and a high band gap material (Al2O3 with a

Eg=8.5 eV) which helps to reduce the leakage current. Capacitors, consisting on

Glass/ITO/TAO(100 nm)/Au, were fabricated using one lithography step. Current-voltage

and capacitance-voltage characteristics were evaluated in order to determine leakage current,

capacitance per area and dielectric constant. It was found that the dielectric constant of TAO

films can be tuned from 15 to 25 as the sub-layer thickness of the Al2O3 and TiO2 films is

decreased from 20 to 5 nm. A minimum leakage current of 10E-7 A was obtained for all the

cases. The effect on the leakage current and the dielectric constant dependency over

frequency was also studied for different TAO total thicknesses of 100, 200 and 300 nm. The

results obtained are encouraging towards application in MEMS technology.




187

[ MEM-220 ] Manufacturing of cantilevers based on

hydrogenated amorphous SiGe films

Margarita Galindo-Mentle 1 , Rosa Maria Woo-Garcia 4 , Rodolfo

Palomino-Merino 3 , Wilfrido Calleja-Arriaga 5 , Carlos Zuñiga-Islas 5 ,

Agustín Leobardo Herrera-May 2 , Francisco Lopez-Huerta


1 Av. Universidad Tecnológica 1000, Xicotepec de Juárez, Puebla, Mexico 2 Centro de Investigaciones en Micro y Nanotecnología, Universidad Veracruzana,

Calzada Ruiz Cortines 455, 94292, Boca del Río, Veracruz, Mexico 3 Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de

Puebla, Av. San Claudio y Río Verde, Col. San Manuel, 72570, Puebla, Puebla,

Mexico 4 Facultad de Ingeniería, Universidad Veracruzana, Calzada Ruiz Cortines 455,

94292, Boca del Río, Veracruz, Mexico 5 Instituto Nacional de Astrofísica, Óptica y Electrónica, Calle Luis Enrique Erro 1,

72840, Tonazintla, Puebla, Mexico

We present a manufacturing process of cantilevers using both boron-doped

hydrogenated amorphous silicon and hydrogenated amorphous silicon-germanium (a-

SiB:H and a-Si0.5Ge0.5B:H) films. The cantilevers are fabricated by plasma enhanced

chemical vapor deposition (PECVD), at 573 K, 110 kHz and a low pressure (0.8 e-3

atm). The proposed microstructures have seven different length with a single

structural layer of 1 µm thickness and are fabricated using surface micromachining.

These microstructures showed a good characteristics for their integration in the

production of MEMS. Our manufacturing process with hydrogenated amorphous

SiGe films is simple and decreases the residual stress of these microstructures.




188

[ MEM-266 ] Manufacturing Piezoresistive Devices

Based on Graphite Films

Luiz Antonio Rasia ([email protected]) 1, Graciane Hammes 2 , Marina

Geremia 2 , Antonio Carlos Valdiero 1

1 Unijuí / DCEEng - Department of Science and Engineering, Rudi Franke Avenue, 540,

Panambi, Brazil 2 Unoesc / University of the West of Santa Catarina, Chapecó, Brazil

In this paper are shown results of the characterization of piezoresistive sensor elements based

on graphite films. The graphite was deposited through direct friction on polymeric substrates.

Using mathematical models were extracted the piezoresistive coefficient, πij, these films. The

results are compared with amorphous DLC films produced by magnetron sputtering

techniques. In these films were obtained longitudinal piezoresistive coefficient in the order

of -3.65x10-10 m2/N transverse piezoresistive coefficient -4.5x10-10 m2/N and shear

coefficients -1.02x10-9 m2/N. Tests have shown that the change in resistivity is proportional

to the load applied to the structure. The proposed arrangement is an alternative way to

produce sensor elements using easier techniques of deposition. The arrangement of graphite

piezoresistores on polymeric substrates should become a substitutive alternative for

conventional force devices, acceleration and pressure made from silicon.




189

[ MEM-449 ] Development of a Virtual Platform for

Piezoresistors Project

Rodrigo Couto Moreira 2 , Luiz Antonio Rasia ([email protected]) 2 ,

Marina Geremia 3 , Sandro Sawicki 2 , Humber Furlan 1

1 FATEC/Centro Paula Souza, Coronel Fernando Prestes,Square, 30,Bom Retiro,

São Paulo, Brazil 2 Unijuí / DCEEng - Department of Science and Engineering, Lulu Ingelfritz Street,

480, Ijuí, Brazil 3 Unoesc / University of the West of Santa Catarina, Chapecó, Brazil

This work shows the development and implementation of a software project for

piezoresistive sensing elements. The program is built in Java and uses the classical

mathematical models of literature for piezoresistors project. There are many programs

that assist piezoresistors projects, but not all are specifically designed for this purpose.

Some are used to simulate stages of the processes of diffusion or implantation of

impurities, others are used to produce the effect of physical and mechanical structures.

In this paper we present a virtual platform that allows you to cross between the

electrical properties, thermal and mechanical semiconductor material chosen for

piezoresistance project. The results are important parameters for the final design of

piezoresistive sensing devices in the laboratory. Otherwise, the platform serves as a

teaching tool designs since the simulation results are shown graphically and can be

experimentally reproduced.




190

[ MEM-455 ] Hybrid energy harvester prototype based

in three different mechanisms: piezoelectric, photovoltaic

and Radio Frequency.

Adriana Limón Morín 1 , Mario Moreno Moreno 3 , Víctor González Díaz 2 ,

Fermi Guerrero Castellanos 2 , Richard Torrealba Meléndez 2 , Aurelio

Heredia Jiménez 4 , Roberto Ambrosio Lázaro


1 Electrical and computing, UACJ, Av. del Charro 450N, Ciudad Juarez, Chih. 2 Electronics department, BUAP, Edif. 109B. Ciudad Universitaria. 18 Sur y Avenida San

Claudio. San Manuel. Puebla, Pue 3 Electronics department, INAOE, Luis Enrique E. 1, Sta. Ma. Tonantzintla, Puebla 4 Mechatronics, UPAEP, Calle 21 Sur.1103, Barrio Santiago, 72410, Puebla, Pue

Harvesting energy is the process of scavenging power from the ambient energy resources.

This ambient energy is related to green energy sources such as solar, thermal, wind,

vibrations and electromagnetic radiation. The amount of energy transformed from the

ambient sources can power up sensor nodes, low power electronic devices and to recharge a

battery, it is a potential solution to realize handheld electronics with long-term operation and

also self-powered electronics, therefore to eliminate the need of changing batteries

frequently. The devices that harvest energy from the ambient require specific environmental

conditions; for instance, solar cells and piezoelectric generators require sunlight and

mechanical vibration, respectively. Since these conditions do not exist all the time, most

energy harvesters do not generate a constant stream of electricity. In order to increase the

output power to bias the electronic systems and to harvest energy continuously is necessary

to combine different types of harvesting mechanisms. In this work is presented the prototype

of a hybrid energy harvesting circuit which integrates piezoelectric, photovoltaic and

electromagnetic energy harvesting mechanisms. It contains a piezoelectric cantilever based

on Lead-Zirconate Titanate piezoelectric transducer (PZT) in order to harvest the ambient

vibrations, a solar cell for sunlight and an antenna capable to harvest ambient Radio

Frequency (RF) energy. The design and implementation of the circuits: AC to DC for the

case of piezoelectric generator, and the antenna and its signal conditioning circuits for RF to

DC are presented. The RF harvesting circuit operates in the 2.45 GHz range with obtained

voltage of 17mV. The prototype is capable to generate a maximum DC power around 241.3

mW when the piezoelectric, solar cell and RF devices are connected together. Thus, the

output power of this hybrid harvesting circuit is very attractive for low power electronic

applications.




191

[ MEM-477 ] Characterizing printed antennas at

microwave frequencies using two popular coaxial

interfaces: a fair comparison

Maria de la Luz Garcia Cruz ([email protected]) 2 , Reydezel

Torres Torres ([email protected]) 1 , Marco Antonio Ramírez Barrientos

2

1 Coord. Electrónica, INAOE. Luis Enrique Erro No. 1, Tonantzintla, Puebla, México C.P.

72840. 2 Fac. Electrónica, UPAEP. 21 sur 1103 Barrio Santiago, Puebla México, C.P. 72410.

Nowadays, printed circuit board (PCB) technology is widely used to implement high-

speed electronic platforms for communication purposes. Therefore, it is highly desirable to

integrate antennas over PCB substrates to reduce cost and optimize area. For this reason,

much research has been carried out to provide designers with methodologies for

implementing reliable antennas on PCB. In fact, printed antennas with different structures

are implemented these days using metal traces separated from the ground plane by composed

dielectrics. These are the well-known microstrip-based antennas, and the pattern for these

devices is selected by considering the frequency range of operation, input impedance, and

radiation pattern, among other important features.

Once the antenna is designed and prototyped, a rigorous verification of its appropriate

operation is required to warranty that the requirements specified for a particular application

are met. In this regard, one of the most important tests performed to an antenna fabricated on

PCB is that carried out to ensure that the frequency of resonance (i.e., the frequency at which

the device is required to operate) as well as the input impedance fall at values within the

tolerances defined at the beginning of the design process. For this purpose, the standard tool

employed to carry out this test is a vector network analyzer (VNA), which applies high

frequency signals to the antenna and measures the power that is reflected back at particular

frequencies within a band specified by the user. Therefore, for practical reasons, in order to

apply and sense signals to a PCB antenna using a VNA, an interface is required. This is due

to the fact that the VNA presents a coaxial connector input/output terminal, whereas the

antenna is terminated with the form of a microstrip line. Thus, bear in mind that not only the

mechanical match of the microstrip with the VNA is necessary, but it is also necessary to

optimize the interface to avoid that the electromagnetic fields applied by the measurement

equipment leaks away from the device under test (DUT) due to undesirable signal reflections.

In a microwave laboratory there are two main forms to practically characterize printed

antennas on PCB: directly using coaxial microwave connectors attached to the board, and

using a universal test fixture (UTF). Both methods present advantages and disadvantages




192

involving several technical aspects; hence, whereas directly using coaxial connectors is a

considerably more popular practice due to the easy and direct implementation, using a

carefully calibrated UTF allows to greatly reduce the effect of the parasitic introduced by the

measurement setup by using a calibration technique that defines the measurement plane at

the level of the DUT. Therefore, the research reported here involves a systematic evaluation

of the error introduced by employing both techniques, allowing the microwave designer to

select the more appropriated approach to characterize a prototype. It is shown that at early

design stages, it would be acceptable to use coaxial connectors since approximate values for

the characteristic impedance defining the input features of the antenna are obtained; similar

results are obtained for the frequency of resonance. Notwithstanding, the acceptable results

obtained in this case, using a UTF is highly recommended for validating the operation of an

antenna on PCB before incorporating the device within the full system. Carefully performed

experiments support these conclusions.

[ MEM-481 ] Microfluidic device fabrication on glass

substrates with deep channels

César Bartolo Pérez ([email protected]) 1 , Claudia Reyes

Betanzo 1

1 Electronics Department, National Institute of Astrophysics, Optics and Electronics, Luis

Enrique Erro # 1, Santa María Tonatzintla, 72840, Puebla, México

In order to fabricate microfluidic devices with deep channels, two masking layers used for

wet etching were characterized. The aim is to reduce their residual stress to avoid defects like

cracks or peeling off that could reduce the quality of the glass surface and the performance

of the device.

First, a bilayer Cr/Cu was deposited by evaporation. Through the variation of the Cu layer

thickness, the stress is reduced. The second masking layer is amorphous silicon deposited by

PECVD. Different deposition conditions were applied, varying the temperature (140-200°C),

pressure (600-900 mTorr) and power (15-30 W), followed by a thermal annealing at different

times.

The stress calculations were made using the Stoney equation and roughness of the films

characterized by AFM measurements. With a bilayer of Cr (50 nm)/Cu (250 nm) has been

obtained microfluidic devices with channels of 83 m deep, while for the amorphous silicon

layer, the depth obtained is 186 m.




193

[ MEM-509 ] Silicon as a MEMS material

Rodolfo Briseño Rodríguez ([email protected]) 1 , Perla Itzel

Alcántara Llanas 1 , Ana Paulina González Arceo 1 , Manuel Bandala

Sánchez 1

1 Microelectronic Systems Department, CIDESI, Av. Playa Pie de la Cuesta 702,

Querétaro, México

The last decades have seen an ever-increasing use of silicon for the fabrication of

miniaturized systems, this development has been driven by the road maps in the

microelectronics industry, but during the last few years the focus of the field is shifting

toward the use of silicon for fabrication of microelectromechanical systems (MEMS) due to

its versatility, its mechanical properties, the wealth of potential silicon-based novel

applications and its cost as is one of the most abundant elements on earth, compatible with

most batch-processed integrated circuits technologies. This work presents an overview of the

reasons why silicon has such an special place in fabrication of MEMS, its advantages,

limitations, and its expected routes of new development.

[ MEM-526 ] A new method for the micromachining of

silicon by a laser-ablation and chemical etching hybrid-

process

Horacio Estrada ([email protected]) 1

1 Centro Nacional de Metrología, Querétaro, QRO

A novel method for the micromachining of silicon wafers will be reported. The purpose in

mind is to find a way to speed up the chemical etching process as well as to achieve the

chemically etching of (111)-silicon wafers to be able to form membranes or other structures

on these substrates. The method includes the ablation with a laser of silicon wafers, followed

by traditional etching processes using KOH or TMAH. The ablation process damages the

exposed surface resulting on a rather random array of 3D grains. The depth of the damage

depends on the power set on the laser. The damaged region can be readily etched out, to yield

a relatively smooth surface after few minutes in the etching solution at temperatures below

the traditional 90oC, widely used for those alkiline solutions. The attractive results of this

hybrid method are the ability to obtain circular membranes on (100)-wafers, which are

usually obtained using plasma etching methods; whereas on (111)-wafers, relatively circular




194

and rectangular deep (200µm) membranes can be achieved within a few hours of etching at

50oC after the corresponding ablation process. Details and results from this work will be

presented, and different perspectives for the use of this hybrid method will be highlighted

for the fabrication of nozzles, or to reduce the plasma etching times and costs, often necessary

when SOI-wafers are included in a device's protocol.

[ MEM-534 ] Design and Fabrication of Touch Mode

Capacitive Pressure Sensor for Biomedical applications

using a Surface Micromachinig Fabrication Module

Daniela Díaz Alonso ([email protected]) 3 , Mario Moreno 3 , Luis Niño

de Rivera 2 , Félix Gil 1 , Juan Manuel Álvarez 3 , Ignacio Juárez 3 , Víctor

Aca 3 , Armando Hernández 3 , Adrián Itzmoyotl 3 , Wilfrido calleja 3

1 APEC, Hospital Luis Sánchez Bulnes, D.F. México 2 IPN ESIME-Culhuacan, D.F. México

3 LI-MEMS INAOE, Puebla, México

This paper presents a new design and fabrication scheme of Touch-Mode Capacitive Pressure

Sensor (TMCPS), which can be used in a wireless integrated RLC implant circuit for

monitoring pressure in biomedical applications. The work is focused on the design,

simulation and fabrication of dynamic capacitors, based on surface micromachining with

Poly-Si and Aluminum films as top electrode, both structural materials were covered with a

1.5µm-thick Polyimide film. The capacitive microstructures have been developed using the

PolyMEMS-INAOE technology® for surface micromachining. The novelty of the method

includes two important aspects: First, the capacitors are designed as a planar cavity within a

rigid frame, where two walls contain channels, which allow etching of the sacrificial material

and simplifies the complementary sealing process to a fully monolithic fabrication scheme.

Second, the electromechanical structures are designed using a composite model, such model

includes a Polyimide film capping for precise pressure sensing, giving protection for the

internal cavity, and at the same time, providing full biocompatibility. Results show the

diaphragms are fully flexible and mechanically stable, the composite model fits perfectly the

mechanical behavior, and the PolyMEMS-INAOE technology® is perfectly suited to develop

pressure sensor devices with manufacture stages at high (Poly-Si) and low temperatures

(Aluminum). In addition, we are presenting a proposal to integrate a telemetric system with

this pressure device for a future implantable stage.




195

[ MEM-542 ] Implementation of a Second-Order Low-

Pass Active Time-Varying Filter with a Symbolic-

Modelled Memristor

Arturo Sarmiento-Reyes ([email protected]) 1 , Luis Hernández-

Martinez 1 , Jesús Jiménez León 1 , Gerardo Ulises Díaz Arango 1 , Hector

Vázquez-Leal 2

1 INAOE, Electronics Department, Luis Enrique Erro 1, 72840 San Andrés Cholula,

Puebla, Mexico 2 Universidad Veracruzana, Faculty of Eectronic Instrumentation

Analog filtering plays an important role in the design of front ends in various systems that

span from signal processing systems, control systems, telecommunications systems to

instrumentation systems. In modern electronics, the requirements for analog filtering

systems are no longer exclusively related to implement a given transfer function in the

frequency domain that fulfills certain specifications related to the gain in a pass band and

attenuation in the reject band, in fact more features have been incorporated to these systems.

Adaptability and programmability are some characteristics that are commonly expected in

the implementation of analog filters in order to make the designs compatible with high

performance electronics. A smart form of incorporating these characteristics to analog filter

design is by generating structures whose parameters change with the time, i.e. time-varying

filters. This can be done by linking a time-dependent function to the constitutive branch

relationships of those elements in the filter structure that define the most important

parameters of the transfer function such as gain, quality factor and cut-off frequency.On the

other side, the specific memory-resistance property of the memristor makes this device

specially suited for implementing time-varying filters. In this paper, the time-varying feature

of the filter is achieved by using a memristor as the element that controls the the parameters

of the transfer function. In this form, the time-dependance of the memristor is reflected in the

overall transfer function of the structure. The result is a filter that possesses identical

frequency-domain response as the original filter plus a faster settling time.

In addition, the memristor is modelled with a fully analytic i-v function that becomes an

excellent feature for including the device in the electric simulation procedure.Waveforms,

transient-response and the complete design flow of the filter are presented in the final

manuscript.




196

NANOSIENCE AND

NANOSTRUCTURES (NSN) Chairmans: Máximo López Lopez (CINVESTAV)

Jaime Santoyo Salazar (CINVESTAV )

Cristo Manuel Yee Rendon (UAS)

Oral Session

INVITED TALK

[ NSN-76 ] Nano-structured ZrO2 co-doped with rare

earth ions with multicolor and white emission

Alma Isabel Ramos Guerra 1 , José Guzmán Mendoza 1 , Manuel García

Hipólito 3 , Ciro Falcony Guajardo 2

1 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, IPN, Miguel

Hidalgo 11500 D.F., México 2 Centro de Investigación y Estudios Avanzados, IPN, Gustavo A. Madero 07360 D.F.,

México 3 Instituto de Investigación en Materiales, UNAM, A.P. 70-360 Coyoacán 04510 D.F.

For this research, the hydrothermal synthesis as well as the characterization in morphology,

structure, chemical composition and photoluminescent properties of intrinsic ZrO2 as well as

co-doped with rare earths ions (RE) is reported.

The intrinsic and co-doped ZrO2 was synthesized using chlorides (ZrOCl2.8H2O,

EuCl3.6H2O, TbCl3.6H2O and TmCl3.6H2O all with a purity of 99.99% from Aldrich brand)

as precursor materials; deionized water as solvent and NaOH to take the solution pH to 12.

The reaction was carried out for 1.5hrs at 200°C; parameters that were kept fix during the

whole synthesis; however, concentration of each dopant was varying in order to determine

the optimal concentration of each RE, results that were used to establish the combination of

RE to obtain luminescent emissions of different colors.

The EDS results confirmed the presence of the rare earth ion in the doped samples and a

stoichiometric relationship close to the ideal. The X-ray diffraction results showed that the

co-doped and the intrinsic ZrO2 powders presented a combination of crystalline structures,

monoclinic and tetragonal, since the dopant concentration was not enough to stabilize only

the tetragonal phase. Furthermore, using this results and Scherrer's formula, the size of the




197

crystal was estimated around 11nm; results that were confirmed through HRTEM. As for the

results concerning luminescent properties, the samples were excited using a wavelength

suitable for the three RE ions. The spectra showed a combination of characteristic emission

lines of each RE present in the sample Tb3+ (5D47F5), Tm3+ (1G4

3H6), and Eu3+ (5D0

7F1 4); apparently with a transfer of energy or an overlap of emission liens. The mixture of

emission lines allowed to have samples with emissions of different colors including white,

since the color of the emission can be controlled with the amount of solution of each dopant

in the synthesis solution

[ NSN-93 ] Structure and luminescence of CdTe

embedded porous silicon

Claudia de Melo ([email protected]) 5 , Guillermo Santana 2 , Jaime

Santoyo 4 , Gabriel Romero 1 , Johnny Ferraz 3 , Moni Behar 3 , Osvaldo de

Melo 5

1 Electrical Engeenering Department, Centro de Investigación y Estudios Avanzados del

Instituto Politécnico Nacional, CINVESTAV-IPN, A.P. 14-740, México D.F. 07360, México 2 Instituto de Investigación en Materiales, Universidad Nacional Autónoma de México, Cd.

Universitaria, A.P. 70-360, Coyoacán 04510, México D. F. 3 Ion Implantation Laboratory, Institute of Physics, Federal University of Rio Grande do

Sul, CP 15051, CEP 91501-970, Porto Alegre, RS, Brazil. 4 Physics Department, Centro de Investigación y Estudios Avanzados del Instituto

Politécnico Nacional, CINVESTAV-IPN, A.P. 14-740, México D.F. 07360, México 5 Physics Faculty, University of Havana, Colina Universitaria, 10400 La Habana, Cuba

Porous silicon (PS) is a promising matrix host for embedding different materials, such as

semiconductors [1,2], metals or conductive oxides [3,4] with a wide range of applications.

This is because the properties of both the PS and the embedded material can be modified in

the final composite. Such composites offer new and interesting properties depending on the

kind of embedded material and its morphology. Several techniques have traditionally been

used to infiltrate PS films. They include sol- gel [5], multiple step process including

impregnation and thermal or chemical treatments [6], atomic layer deposition [7], and

electro-deposition [8] among others.

In this work, the results of using isothermal closed space vaporization technique (ICSV) for

embedded CdTe in porous silicon (PS) are presented. The structure of the embedded material

is determined by X-ray diffraction analysis, which allows identifying the formation of two

different crystalline phases of CdTe. Micrographs of the samples taken with transmission and




198

scanning electron microscopes allow determining the size of the PS pores, and the size and

shape of CdTe grains grown on the inner surface of PS. Direct measurements of

compositional profiles through Rutherford backscattering spectrometry (RBS) are presented;

these measurements allow demonstrating the feasibility of this technique to incorporate the

CdTe inside the pores of mesoscopic PS.

We show that filling of PS with CdTe causes changes in the PS refractive index and in their

luminescent properties. While the virgin PS shows the typical red emission, the embedded

one displays an intense wide emission at room temperature along the whole visible range.

Measurements of photoluminescence vs. temperature from 11 K up to 288 K allow

identifying two different emission bands: a red and a blue band. The behavior of the energy

gap and integrate intensity vs. temperature suggest the red emission arise not from the CdTe,

but from the PS itself; the role of CdTe is to promote this emission trough passivation of the

PS surface. We believe that this emission is associated to direct recombination of photo

generated carriers into Si nanocrystals. On the other hand the energy of the blue band

practically does not change with temperature, due to that we suppose that it arise from

transition of deep levels inside the SiO2 gap.

[1] C. de Melo, S. Larramendi, V. Torres-Costa, J. Santoyo-Salazar, M. Behar, J. Ferraz-

Dias, O. de Melo, Micropor. Mesopor. Mater., 188, 93 (2014).

[2] O. de Melo, C. de Melo, G. Santana, J. Santoyo, O. Zelaya-Angel, J. G. Mendoza-

Álvarez, and V. Torres-Costa, Appl. Phys. Lett., 100, 263110 (2012).

[3] R. G. Singh, F. Singh, V. Agarwal, R. M. Mehra, J. Phys. D: Appl. Phys., 40, 3090 (2007).

[4] P. Granitzer, K. Rumpf, Materials, 3, 943 (2010).

[5] Szilági, Z. Hajnal, F. Pászti, O. B uiu, G. Craciun, C. Cobianu, C. Saaniu, É. Vázsonyi,

Mater. Sci. Forum, 248, 373 (1997).

[6] A. I. Belogorokhov, L. I. Belogorokhova, A. Pérez-Rodríguez, J. R. Morante, S. Gavrilov,

Appl. Phys. Lett., 73, 2766 (1998).

[7] C. Docsö, N. Quoc Khanh, Z. Horváth, and I. Bársony, M. Ufrialnen, S. Lebto, M.

Nieminen, L. Niinistö, J Electrochem. Soc., 143, 683 (1996).

[8] Farid A. Harraz, Tetsuo Sakka, Yukio H. Ogata, Electrochim. Acta, 50, 5340 (2005)




199

[ NSN-94 ] Basic Modification of Multi-walled Carbon

Nanotubes (MWCNT) by Heating Reflux for Possible

Application as Catalysts in Biodiesel Production

Christian Cabello Alvarado ([email protected]) 3 , Pascual

Bartolo Pérez 1 , Susana Rincón Arriaga 2 , Alejandro Zepeda Pedreguera 3 ,

Julio Sacramento Rivero 3

1 CINVESTAV-Unidad Mérida, Carretera antigua a Progreso Km 6, A.P. 73 Cordomex, C.

P. 97310, Mérida, Yucatán, México. 2 Instituto Tecnológico de Mérida, Av. Tecnológico Km. 4.5 S/N, C.P. 97118, Departamento

de Ingeniería Química-Bioquímica, Mérida, Yucatán, México. 3 Universidad Autónoma de Yucatán, Facultad de Ingeniería Química, departamento de

química inorgánica, Campus de Ingenierías y Ciencias Exactas, Periférico Norte Km. 33.5,

Tablaje Catastral 13615, Col. Chuburná de Hidalgo Inn, C.P. 97203, Mérida,

Between the alternatives to replace fossil fuels it has been proposed the use of new products

that do not damage the environment and generate lower cost. Biodiesel is an excellent energy

to offset the high cost of petroleum diesel. This biofuel consists of alkyl esters from vegetable

oils or animal fats that react chemically with short chain alcohols in the presence of a catalyst

to carrying out the transesterification reaction. The catalysts can be classified in

homogeneous and heterogeneous as zeolites, sulfonic resins, some oxides and carbon-based

catalysts. The multi-walled carbon nanotubes (MWCNT) have properties as high mechanical

strength, exceptional electrical properties and thermal resistance, also the elevated relation

of diameter-length and high surface area make them suitable for application in the field of

catalysis. Additionally of these characteristics, through chemical oxidation of the MWCNT

can be added various functional groups as carboxylic acids, amines and amides, which helps

their interaction with other molecules. This research focuses on study the production of

MWCNT modified whit amines by heating reflux, to establish processes for obtaining

nanoparticles that can be used as catalysts in the production of biodiesel. The nanocatalysts

characterization was performed by XPS spectroscopy and SEM-EDX analysis and stability

tests to confirm dispersed suspensions of the modified nanoparticles. The results of XPS

spectroscopy using modified MWCNT showed the presence of a peak in 399.9 eV

corresponding to N1s, while the unmodified MWCNT not signal appears. The other peaks

were identified to C1s (284.43 eV) with high intensity and related O1s (532.16 eV) low

intensity. In the SEM-EDX analysis the presence of nitrogen it was observed in the EDX

spectra for the modified MWCNT. In the semicuantitative analysis the values obtained were

of 90.01 wt % for C, 3.29 wt % for O and 6.7 wt % for N, in the pristine MWCNT the nitrogen

was not detected. Dispersions of the modified MWCNT were stable for 24 hours in polar

solvents.




200

[ NSN-97 ] Controlled Synthesis and Formation

Mechanism of Silver Nanowire

Didier Castañeda García 3 , Alejandro Rodríguez Juárez

([email protected]) 4 , Josefina Aguila Lopez 3 , Joel Díaz Reyes 1 , Jesús

Antonio Fuentes García 4 , Jaime Santoyo Salazar 2 , José Luis Jiménez

Pérez 4 , José Francisco Sánchez Ramírez ([email protected]) 1

1 CIBA-Instituto Politécnico Nacional. San Juan Molino Km 1.5 de la Carretera Estatal

Sta. Inés Tecuexcomac-Tepetitla, Tlaxcala, 90700. México. [email protected] 2 Centro de Investigación y de Estudios Avanzados de Instituto Politécnico Nacional,

Departamento de Física, Av. IPN 2508, San Pedro Zacatenco, C.P. 07360, A.P. 14-740,

07000 México, D.F., Mexico 3 Instituto Tecnológico Superior de Tlaxco, Predio Cristo Rey Ex Hacienda de Xalostoc s/n

Carretera Apizaco Tlaxco Km. 16.8 C.P.90250 Tlaxco Tlaxcala, México 4 UPIITA-Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2580. Barrio

Laguna Ticoman 07340. México D. F.

The synthesis of silver nanowires (Ag NWs) with high quality is challenging because of the

low selectivity of the formation of multiply twinned particles at the nucleation stage for

subsequent Ag NWs growth. We report a systematic study of the controlled synthesis of Ag

NWs with high rate in a simple and scalable preparation method. Using glycerol as a reducing

agent and a solvent with a high boiling point, the reaction is rapidly heated to 150 °C in air

to synthesize Ag NWs with a very high yield in gram level. The obtained Ag NWs are highly

crystalline, monodisperse and exhibit adsorption in the range of 350−400 nm. By simply

varying the temperature of reaction, the formation of Ag NWs can be controlled. Visual color

changes between 40 - 140 °C were observed in the colloidal dispersions. The formation of

Ag NWs has been confirmed using the techniques UV-Vis spectroscopy, XRD and TEM. A

possible growth mechanism of the Ag NWs is given.

The authors are thankful to the Mexican Agencies, CONACYT, SIP-IPN and COFAA-IPN

for financial Supports.




201

[ NSN-108 ] Cubic GaN grown on GaAs substrates by

RF-plasma-assisted Molecular Beam Epitaxy

Y.L. Casallas-Moreno ([email protected]) 5 , D. A. Flores-

Cordero 1 , S. Gallardo-Hernández 5 , B. M. Monroy 4 , A. Hernández-

Hernández 3 , G. Santana 4 , A. Escobosa-Echavarría 2 , M. López-López 5

1 Chemical Department, Escuela Superior de Ingeniería Química e Industrias Extractivas 2 Electric Engineering Department, Centro de Investigación y de Estudios Avanzados del

IPN 3 Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo

4 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México 5 Physics Department, Centro de Investigación y de Estudios Avanzados del IPN

GaN epitaxial films with high cubic phase purity were grown on GaAs(100) substrates by

RF-plasma-assisted Molecular Beam Epitaxy (RF-MBE). The films were synthesized at

different growth temperatures ranging from 710 to 730°C. An As overpressure was employed

during the nucleating layer. We found the optimum conditions for the nucleation of the cubic

GaN using the As overpressure. Higher cubic phase of GaN was obtained for samples that

initiated the relaxation process after some monolayers (8ML) of growth, as a result of better

stabilization of the cubic layer. The relaxation process depends on the As overpressure over

the growth surface and on the growth temperature. The structural details of GaN by high-

angle annular dark-field STEM (HAADF-STEM) and high resolution X-ray diffraction (HR-

XRD) evidenced the purity of cubic phase in the first nanometer of growth, and also the

formation of planar defects as stacking faults. We identified the stacking faults along the

[111] planes, as result of the strain relief caused by the large lattice mismatch between GaN

and GaAs, and the incorporation of hexagonal phase over these facets. The identification and

quantification of h-GaN was performed by X-ray reciprocal space mapping (RSM). We

obtained the highest cubic phase purity of 98.7% for cubic GaN grown at 720°C. The

photoluminescence spectra of the samples clearly show emission peaks of c-GaN. This work

was supported by Sener-Conacyt No. 151076.




202

INVITED TALK

[ NSN-117 ] Nano and micro structures in alkali halide

films produced by pulsed laser deposition

Dwight Acosta ([email protected]) 2 , Elsi Mejia 1 , Citlali Sanchez 1

1 Centro de Ciencias Aplicadas y Desarrollo Tecnológico de la UNAM 2 Instituto de Física de la UNAM

The alkali halide (AH) family are materials with cubic symmetry and it is constituted by positive

sodium or sodium ions and negative chloride ions. These compounds are insulators with wide band

gap and by its simple crystalline composition are often used as model structure to validate and try

new theories and experiments. Thus, recently these materials have been researched as promising host

for self-assembly of luminescent nanostructures. The AH are synthesized with different growth

processes in bulk and thin film configuration, according to faces the electric properties change, thus

for the NaCl the (100) surface is electrically neutral and (111) surface is electrically charged.

Arranging and control of atomic structures and molecular on insulating thin film are of great interest

in device miniaturization. In the insulating materials, and in particular in NaCl, the epitaxial growth

of thin films and its self-assembly process is highly important for nanotechnological applications due

to its high-quality in the growth of layer by layer .

Monocrystalline NaCl and KCl materials, from International Crystal Laboratories, were used

respectively as targets during Pulsed LaserDeposition process, which in turn, was carried out in an

UHV chamber at pressure 10 mTorr using excimer laser at 248 nm, with an output energy 50 mJ at

10 Hz. The PLD system used operation was controlled with a computer. The substrates were located

in front o the target and several distances target-substrate were tried : 45, 55, 60, 70, 80 mm. The

substrate temperature was increased from room temperature up to 300, 400 and 500 ºC respectively

and the number pulses was rised sequentially from 4800 to 24000 shots.

The characterization of thin films was carried out with a SEM JEOL LV 5600 and a STEM JEOL

2010 electron microscopes, a Bruker D8-Discovery X-rays diffractometer, an AFM AutoProbe CP

(Park Scientific Instruments). Nano and micro thin films were produced by PLD on glass and on

polymer substrates From SEM and STEM micrographs analysis the simultaneous ocurrence of three

growing process can be stablished:1)The atomic and molecular clusters formation, 2) the micro

and nano grains coalescence process 3) the self ensamble of the nanocrystal cluster as a function of

substrate temperature, deposition chamber pressure and laser pulses number. Electron micrographs

suggest that nucleation and coalescence rates are different for nano and micro AH crystallites, during

film synthesis and the big crystallites do not growth at the expenses of small ones while the flow of

alkali halide material from target is impinging continuously on substrate

The results suggest that beside the clasics films growth models (Volmer-Weber, Frank- van der

Merwe and Stranski-Krastanov) other possibilities must be considered to explain the Alkali Halides

films formation and growth under PLD deposition.




203

[ NSN-325 ] Influence of zinc acetate on the glass coating

for the growth of zinc oxide nanowires by hydrothermal

method

Marco Alberto Ayala-Torres ([email protected]) 1 , Concepción

Mejía-García 1 , Josué Romero-Ibarra 2 , Gerardo Ortega-Cervantes 1

1 ESFM - IPN 2 IIM - UNAM

In this work, the study of the glass substrate coatings where the ZnO nanowires grow was

carried out. The glass coating was performed by centrifugation, zinc acetate solutions of 1,

10 and 100 mM in 1-propanol, with three cycles of spin coating at 2000rpm for 100s were

deposited. At the end of each cycle the substrate was introduced in a muffle furnace for 1

min at 100°C. ZnO nanowires were obtained immersing the substrates in an equimolar

solution of zinc nitrate hexahydrate and hexamethylenetetramine (HMTA) to 25 mM in

deionized water. A commercial microwave oven at different power settings of 300, 500 and

700W for 20 min for the thermal treatment was used. The ZnO nanowires obtained were

characterized structural, optical and morphologically using XRD, UV-VIS transmission and

Scanning Electron Microscopy (SEM), respectively. XRD patterns spectra revealed the

presence of Zn(OH)2 on the films. The ZnO nanowires bandgap energy for the films grown

on glass was obtained optical transmission spectra (3.24 eV). The influence of the zinc

acetate concentration in the coating density and the morphology of the nanowires was

studied.




204

[ NSN-337 ] Growth and characterization of MoSe2 single

crystals and MoSe2-MoS2 heterostructures

Andres de Luna Bugallo ([email protected]) 1 , Daniel Rubin 3 ,

Fangze Liu 3 , Estelle Cohen 2 , Swastik Kar 3

1 CINVESTAV-Queretaro 2 Harvard University

3 Northeastern University

Over the last decade, a considerable amount of bi-dimensional materials have been obtained

either by exfoliation or deposition techniques including the possibility to form

heterostructures [1,2]. Among all these new nano-materials, transition metal dichalcogenides

(TMDs) particularly Molybdenum and Tungsten based TMDs are intrinsic semiconductors

with well defined bandgap values between 1-2 eV, making them promising candidates for

many optoelectronic and nanoelectronic applications[3].

In this work we present the synthesis and characterization of single layer MoSe2 crystals as

well as a novel method obtain MoSe2-MoS2 vertical and lateral heterostructures. First, MoSe2

nanosheets were grown using chemical vapor deposition (CVD) on SiO2. Micro-Raman

spectroscopy shows dependent thickness on the vibrational modes, monolayers present a

photoluminescence enhancement related to the indirect to direct bandgap crossover. MoSe2

FET devices were fabricated by means of e-beam lithography, backed gated measurements

revealed high gate mobility around 20cm2V-1s-1. The devices also show a photoresponse of

2 orders of magnitude under UV illumination.

Lateral and axial MoSe2-MoS2 monolayer heterostructures were epitaxially grown using a

simple and controllable technique based on a CVD two-step process. Micro-Raman and PL

spectroscopy and imaging show spatially contributions of different vibrational modes and

luminescence of the two materials over the structures. In particular photoluminescence

spectra show that the emission can be tuned from 1.55 to 1.85 eV. Finally crystallinity of the

MoSe2-MoS2 heterostructures was studied by transmission electron microscopy (TEM).

[1] Sheneve B. et. al. ACS Nano, 2013, 7 (4), pp 2898–2926

[2] Yongji G. et. al. Nature Materials 13, 1135–1142(2014)

[3 ]Fengnian Xia, Han Wang, Di Xiao, Madan Dubey & Ashwin Ramasubramaniam, Nature

Photonics 8, 899–907(2014)




205

[ NSN-382 ] Study of the formation of Au nanoparticles

produced by pulsed laser annealing

Citlali Sánchez-Aké ([email protected]) 1 , Jimena Martínez

de León 1 , Tupak García-Fernández 2 , Mayo Villagrán-Muniz 1

1 Laboratorio de Fotofísica, Centro de Ciencias Aplicadas y Desarrollo Tecnológico,

Universidad Nacional Autónoma de México, Apartado Postal 70-186, México D.F., C.P.

04510, México 2 Universidad Autónoma de la Ciudad de México (UACM), Prolongación San Isidro 151,

San Lorenzo Tezonco, México D.F., C.P. 09790, México

Metallic nanoparticles (NPs) either covered or embedded in dielectric matrices like glasses

have received great attention for their linear and non-linear optical properties and its possible

applications as plasmonic structures. One suitable technique for the synthesis of metallic NPs

is pulsed laser annealing. In this method, laser irradiation of thin metal films on non-wetting

substrates produces heat instabilities and melting that lead to the disaggregation of the film

into nanoislands and nanoparticles. Moreover, it has been shown that for laser fluences above

a certain threshold, the NPs can be implanted into glass substrates [1]. This technique can be

perfomed at room temperature and atmospheric conditions and is free of chemical wastes and

lithography requirements [2].

The aim of this work is to investigate the formation of gold NPs using in situ characterization

techniques. The NPs were produced by laser annealing of Au films on both glass and fused

silica substrates. We employed a Nd:YAG laser emitting pulses of 7 ns of duration and 355

nm. With the aim to better understand the mechanisms involved during the annealing, real-

time optical absorption, laser beam deflection and pulsed photoacoustic measurements were

used to monitor the formation of the NPs. The obtained NPs were characterized later by SEM

and UV-Vis optical absorption. The influence of the laser fluence, number of pulses,

repetition rate, film thickness and the background pressure on the characteristics of the NPs

was studied.

[1] S.J. Henley, M.J. Beliatis, V. Stolojan, S.R.P. Silva, "Laser implantation of plasmonic

nanostructures into glass", Nanoscale 5, 1054 (2013).

[2] M.J. Beliatis, N.A. Martin, E.J. Leming, S.R.P. Silva, S.J. Henley, "Laser ablation direct

writing of metal nanoparticles for hydrogen and humidity sensors", Langmuir 27(3), 1241

(2011).




206

[ NSN-393 ] Mechanisms for the Self-Assembly of GaAs

Nanofacets in High-Index GaAs Substrates prepared by

MBE

Reyna Méndez Camacho ([email protected]) 1 , Victor Hugo

Méndez García 1 , Esteban Cruz Hernández 1

1 Coordinación para la Innovación y la Aplicación de la Ciencia y Tecnología, CIACYT-

UASLP, Sierra Leona 550, S. L. P., S. L. P., México.

Controlled formation of periodically ordered one-dimensional (1D) nanostructures is

interesting for fundamental science and applications [1]. Among the variety of methods

available for the 1D semiconductor quantum wires (QWRs) fabrication, self-assembly on

high index (H-I) substrates by molecular beam epitaxy (MBE) is very promising because

does not require additional processing that may introduce defects to the nanostructures.

Natural formation of periodic corrugation in H-I substrates it is due to the energetic unstable

surfaces that tend to break up into low free-energy surfaces, which then can be used as

templates for growing QWRs arrays with high uniformity and density. However, in spite of

the substantial experimental investigation on self-assembling of uniform corrugation on H-I

GaAs substrates [2], there is a lack of theoretical studies concerning to the surface atomic

mechanisms behind the origin of nanoscale corrugation.

In this work, we report the study of the self-induced surface corrugation in the MBE

homoepitaxial growth of GaAs on GaAs(631) through Density Functional Theory (DFT) by

using a Perdew-Zunger (LDA) exchange-correlation pseudopotential. We found that the

assembling of the ~ 60 nm-width terraces of the surface corrugation is triggered by the

formation of smaller ~ 4 nm-long nanofacets. A generalization of this mechanism for other

H-I orientations is also discussed.

[1] V. A. Shchukin and D. Bimberg, “Spontaneous ordering of nanostructures”, Rev. Mod.

Phys., Vol. 71, 4, (1999).

[2] E. Cruz-Hernandez, et al., Appl. Phys. Lett. 101, 073112 (2012).

Acknowledgments: The author acknowledges the financial support of CONACYT, CeMIE-

SOL 22, FRC-UASLP, INFR-2015-01: 255489, PNCPN2014-01: 248071, and CB: 168761.




207

[ NSN-411 ] Analytical study of In shallow implanted

GaN

Carlos Hernández Gutierrez ([email protected]) 3 , Yuriy

Kudriavtsev 2 , Maximo López López 1 , Victor Sánchez Resendiz 2 , Arturo

Escobosa Echavarria 2 , Jaime Santoyo Salazar 1 , Angel Guillen 1

1 Departamento Física, Cinvestav 2 Departamento Ingeniería Eléctrica - SEES, Cinvestav

3 Doctorado en Nanociencias y Nanotecnología, Cinvestav

Ion implantation is a widely used method to form a p- or n-type semiconductor layers. In last

years the ion implantation became a very popular technique to form metal and semiconductor

nano-particles inside of oxides [1-4].

We performed a low energy (25keV) and a high doses (from 2.5 to 5 x1015 ions/cm2)

implantation of Indium in GaN epi-layers, grown by MOCVD on a sapphire substrate. Both

p-type (Mg doped) and n-type (Si- doped) GaN epi-layers were used. The energy and the

doses were selected to reach the In concentration of around 5-7 atomic % at the implanted

maximum. After implantation the samples were heated in ammonia atmosphere under 400oC

during 30 minutes. Two possible results have been suggested originally: a formation of InN

(or In) nano-particles in a near surface GaN layer, or a formation of top InxGa1-xN ternary

layer. To confirm or reject the suggestions we performed a complex analytical study of the

implanted and annealed samples by using SIMS, RAMAN, TEM, XRD and PL methods.

Raman confirmed formation after implantation of In-N bonds and demonstrated indium

oxide peaks, as well. The last peaks disappeared after a thermal annealing in ammonia

atmosphere. SIMS showed a quite similar In distribution before and after annealing. XRD

with a glancing angle confirmed a formation of InxGa1-xN ternary with different composition

(x). PL spectrum shown several peaks, which were indentified corresponding to electron

transitions in InxGa1-xN ternary. But after all, TEM images demonstrated a formation of nano-

particles (InN?) with the typical dimension of around 10nm.

In this report we discuss obtained results and speculate about possible applications of In high

doses implantation in III-nitrides structures.

Reference

[1] A.E. White et al. Appl.Phys.Lett. 50 (1987) 95

[2] M.Strobel, S.Reiss, K.H.Heinig, Nucl. Instr. Meth. B120 (1996) 216

[3] B.Schmidt, K.H.Heinig, A.Mücklich, Mat. Res. Soc. Proc. 647 (2001) 011.20.1

[4] A. W. Wood, X. Weng. Applied Physics Letters 99, 093108 (2011)




208

[ NSN-431 ] Nanoparticles produced by laser ablation in

liquid enviroment

Luis Alberto Hernández-Hernández ([email protected]) 5 ,

Arturo Hernández-Hernández ([email protected]) 4 , Jaime Santoyo-

Salazar 2 , Francisco de Moure-Flores 6 , José Guadalupe Quiñones-Galván

1 , Miguel Meléndez-Lira 3

1 Centro Universitario de Ciencias Exactas e Ingenierías, Blvd. Marcelino García

Barragán #1421, esq Calzada Olímpica, C.P. 44430, Guadalajara, Jalisco 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados - I.P.N.,

C.P.07360 México, D.F 3 Departamento de Física, Centro de Investigación y de Estudios Avanzados - I.P.N.,

C.P.07360 México, D.F. 4 Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo, Calle Ejido de 5 Escuela Superior de Física y Matemáticas – Instituto Politécnico Nacional, Edificio No.

9, U.P.A.L.M., San Pedro Zacatenco, C.P. 07738 México D.F. 6 Facultad de Química, Universidad Autónoma de Querétaro, Querétaro C.P. 09790

México

The formation of ZnS, ZnO, Ge, Si and SiGe alloy nanoparticles under laser ablation of solid

targets in liquids environment is reported. The use of an Nd:YAG laser allow high rate of

nanoparticles formation as a sol. The nanoparticles are characterized by X-ray diffraction

(XRD), UV-Visible transmission spectroscopy and transmission electron microscopy

(TEM). The nanoparticles size dependence on both the laser fluence and the nature of the

liquid is studied. In some cases, nanoparticles of compounds are formed via reaction of the

target whit the liquid.




209

[ NSN-490 ] Structural and compositional analysis in

Zinc Oxide-Graphene Oxide.

Edith Bravo Gonzalez 2 , Aaron Israel Diaz Cano 2 , Efrain Rubio Rosas 1 ,

Yosemik Arjuna Leon Nataret ([email protected]) 2

1 Benemerita Universidad Autónoma de Puebla, CUVYTT, San Manuel,

72570, México 2 Instituto Politécnico Nacional, UPIITA, Gustavo A. Madero, 07340,

México

The optical and structural properties were discussed for the Zinc Oxide-Graphene Oxide

(ZnO-GO) nanomaterial. It used a physical method to grow the material using the Microwave

Assisted Hydrothermal method. The preparation were using 0.07 mmol of

Zn(CH3COO)2∙2H2O and 0.5 M NaOH in 50 ml aqueous solution, stirred for 30 min. The

GO was synthetized by the modified Hummers method and applied sonication for 10 min. In

the prepared solution it added 0.3 ml GO, 5 ml DFM (Dimethylformamide) and 15 ml H2O

deionized to teflon container. The digestion oven parameter were for the first step 5 min –

800W – 130°C – 15 min and the second 15 min – 700W – 110°C. Finally the samples were

cooled 20 min for his subsequent extraction, washed with Ethanol, centrifuged at 3500 rpm

and dried at 55°C for 5 hrs. XRD obtained information about the crystalline structure and

shown a hexagonal phase to correspond to wurtzite structure (JCPDS 36-1451) in relation to

ZnO and a little peak in 22.5° (2theta degree) that could be to relate with GO due to

approximation with FCC graphite phase (002) and the chemistry exfoliation process. An

unusual morphology was observed by SEM analysis, the material has an appearance like

tulip with nanometric sizes (150-500 nm) and homogeneous surface, this structure resembles

a fractal configuration. EDS microanalysis obtained weight values of 24.89%W, 23.68%W

and 51.43%W for C, O and Zn respectively like atomic relation. FTIR obtain information

about the chemical bonding in the material. It has bands attributed to vibrational modes like

H-O-H assigned to a small amount of H2O in the ZnO nanocrystals around 1592 cm-1, bands

in 828 cm-1 and 678 cm-1 are assigned to the vibrational frequencies due to charge in the

microstructural features into Zn-O lattice. The Zn-O bond is assigned to stretching frequency

at 542 cm-1 for pure ZnO and the O-H vibrational frequencies at 3326cm-1. For GO functional

groups the bands attributed to vibrational mode are C-O, O=C=O, C-H, O-H, -COOH

centered in 1242cm-1, 2320 cm-1, 2933 cm-1 and 3354 cm-1 respectively. PL spectroscopy

shows different emission bands associated to defects and the modification of ZnO crystal

structure due to incorporated of GO in the lattice´s material, the pure ZnO in the lattice and

the ability of ZnO particles to transfer photogenerated electrons to GO has been demonstrated

from quenching of ZnO emission.




210

[ NSN-522 ] Strain Distribution of InAs Nanostructures

Grown on GaAs by MBE.

Eric Eugenio López ([email protected]) 1 , Irving Eduardo

Cortes Mestizo 1 , Víctor Hugo Méndez García ([email protected]) 1

1 Center for the Innovation and Application of Science and Technology (CIACyT),

Autonomous University of San Luis Potosí (UASLP), Av. Sierra Leona #550, Lomas 2a

Sección, SLP 78210, México.

The Quantum dots (QDs), being the only structures that present atom-like properties, are the

most promising candidates for developing the next-generation technologies. Although

several major challenges have still to be overcome for the improvement of the QDs quality

and distribution, these nanostructures are often considered as the basis for numerous nano-

electronic devices and applications. The QDs are commonly grown on dissimilar materials

(different lattice constant and parameters) to propitiate the accumulation of strain in the

interface, which is the main mechanism of the formation self-assembled QDs, the Stransky-

Krastanov growth mode. In such cases once the nucleation of the QDs is achieved, due to the

lattice mismatch, the strain in the structure is reduced but also a thin InAs wetting layer (WL)

remains below the QDs. The remaining strain within the QDs is known to impact their

electronic structure and therefore their opto-electronic properties. On the other hand,

photoreflectance (PR) spectroscopy is a technique focused on the band bending modulation

(i.e. surface electric field modulation) [1]. This spectroscopy, as expected, is sensitive to the

electric field produced by the remaining strain in the heterostructure, therefore able to study

it. In this work the strain distribution involved in the whole structure InAs/GaAs was studied:

inside the InAs 3D nanostructures, along the 2D wetting layer, and in the bulk GaAs

substrate. The effect of strain on the energy bands split is analyzed by two-dimensional

simulation of hydrostatic strain in the QDs structure. The simulation indicates that the energy

band diagram is modified by the WL thickness and the QDs topology, which determine the

strain in the GaAs topmost monolayers. Our numerical results are supported by experimental

analysis performed by PR.

[1] J. Misiewicz, Opt. Elec. Rev. 20(2), 101 (2012).






211

Sesión Poster

[ NSN-39 ] Influence of silicon dioxide nanoparticle on

the mechanical properties of concrete mixtures

Fernando Marcial ([email protected]) 2 , Leandro García 1 , Julián

Hernández 1 , Arturo Ayon 3

1 CENTRO DE INVESTIGACION EN MICRO y NANOTECNOLOGIA, UNIVERSIDAD

VERACRUZANA, Calzada Ruiz Cortines # 455, Fracc. Costa Verde, C.P. 94294, Boca del

Río, Veracruz. MEXICO 2 FACULTAD DE ING. MECANICA ELECTRICA, UNIVERSIDAD VERACRUZANA,

Lomas del estadio S/N, Col. Zona Universitaria, C.P. 91000. Xalapa, Ver, MEXICO. 3 MEMS Research Laboratory Dept. of Physics and Astronomy. The University of Texas at

San Antonio, USA

Abstract.

We describe the influence of silica nanoparticles in the compressive strength of a concrete,

hereby referred to as nanoconcrete. The exercise comprised the preparation of two types of

mixtures, namely, (i.) Portland Composite Cement (CPC 30R), sand and coarse aggregate

(gravel) with water cement (W/C) ratio of 0.59 and (ii.) the aforementioned components plus

silica particles (sand grains with 95% of SiO2) to produce nanoconcrete. The exercise

included several nanoconcrete samples that were prepared by varying the content of the silica

particles in the proportions of 15%, 20% and 30% by weight of CPC 30R cement used while

preserving the W/C ratio = 0.59. These prepared mixtures were tested in their fresh and hard

state under uniaxial compression. In order to correlate the observed performance with the

microstructure of these blends, the mixtures were characterized employing X-Ray

Diffraction (XRD) to determine the size of the particles of silica (56 nm) and cement CPC30R

(130 nm), Scanning Electron Microscopy (SEM) to observe the microstructure of the

produced concrete samples, and Energy Dispersive X-Ray Spectroscopy (EDS) to obtain the

specific mineralogical components of concrete and nanoconcrete. The measure response

indicated that strength increased by 15% when silica nanoparticles where added to the

mixture paving the way for the prospective proliferation of this technique.

Keywords. Nanoparticles of silica sand, concrete nanostructured, concrete pattern,

nanoconcreto, CPC30R Portland Cement.




212

[ NSN-43 ] Study of two and three interacting particles in

Graphene type lattices within the Gereralized Hubbard

Model

Edmundo Emmanuel del Muro Arteaga ([email protected]) 1 ,

Sergio Molina Valdovinos 1 , Jaime Raúl Suárez López 1

1 Universidad Autónoma de Zacatecas, Unidad Académica de Física, Calzada Solidaridad

esq. Paseo, La Bufa s/n, C.P. 98060, Zacatecas, Zac. México.

Graphene, a two-dimensional material formed by a single layer of carbon atoms ordered in a

honeycomb lattice. Electron-electron interactions in graphene are expected to play an

important role due to its low dimensionality, and many-body effects have received great

attention [1,2]. In this work, we study the electronic correlation for two and three interacting

particles with parallel and antiparallel spins in a graphene lattice using a real space method

previously reported [3], and the generalized Hubbard model, which includes interactions

between electrons at the same site and at nearest neighbours sites, and also an occupation

dependent hopping. The method consists in mapping the many body problem in an equivalent

one described by an tight binding Hamiltonian with site and bonding impurities. Using

translational symmetries of impurities, we can project the states space in a lower dimensional

one. Then, we analyse electronic correlation by the calculation of the bonding energy, that

is, the energy difference between the bonding state and the non-bonding state of lowest

energy, for different values of the hopping parameter and potential interactions. We obtain

the behaviour of the wave function and its physical implications in the graphene lattice when

electronic correlations are present.

Keywords: electronic correlation, graphene, electrical and electronic properties

[1] Phys. Rev. B 77, 073412 (2008).

[2] Phys. Rev. Lett. 111, 036601 (2013).

[3] Phys. Rev. B 77, 115410 (2008)




213

[ NSN-45 ] Optical near field diffraction by a conducting

double slit under Leontovich impedance boundary

approximation

Juan Sumaya Martinez ([email protected]) 2 , Gustavo Montiel

Gonzalez ([email protected]) 1

1 Physics Dept., Universidad Autonoma del Estado de Mexico 2 Physics Dept., Universidad Autonoma del Estado de Mexico. Instituto Literario 100,

Col.Centro. Toluca, Edo. Mex.

The optical near field diffracted by a metallic double slit ruled in a thick conducting metallic

screen is numerically studied. The Leontovich impedance boundary condition is used at the

metallic interfaces for gold, silver and aluminum. Using incident plane waves the optical near

field is computed above, within and below the double slit system for the two fundamental

cases of polarization S and P. The diffracted field is analyzed as a function of the slit width

(particularly at the subwavelength regime), the reffractive index of the metal and the

thickness of the metallic screen. Finally a comparison with the case of a perfect conducting

screen is performed.




214

[ NSN-50 ] Effect of stirring speed in the structural

properties of pbse nanoparticles obtained by colloidal

synthesis

Edgar Cabrera Guerrero ([email protected]) 1 , Enrique Rosendo Andres 1 , Roman

Romano Trujillo 1 , Gabriela Nieto Caballero 2 , Tomas Diaz Becerril 1 , Hector Juarez

Santiesteban 1 , Mauricio Pacio Castillo 1 , Godofredo Garcia Salgado 1

1 CIDS-ICUAP 2 FCQ-BUAP

Nanoparticles of lead selenide (PbSe NPs) have been obtained through colloidal synthesis in

aqueous solution. The synthesis was carried out at room temperature and the stirring speed

was varied 60 to 1200 r.p.m. HRTEM measurements shown that the distance between planes

are 0.24 nm y 0.36 nm associated with (220) and (111) crystalline planes of PbSe

respectively. SEM measurements shown that all samples the presence of agglomerates of

PbSe is observed, however the presence of bars which may be selenium is also appreciated,

but also as the value of revolutions increases, these bars disappear. The crystal sizes are 10-

13 nm, 11-14 nm and 12-15 nm for molar concentrations of (1:1), (1:2) and (1: 3)

respectively as was calculated XRD measurements, also was found that the PbSe NPs have

the face-centered cubic phase. Micro-probe Raman spectroscopy was used to prove the

existence of optical phonon mode LO(Г) of PbSe nanoparticles prepared by colloidal

chemistry. EDS analysis shown the 1:1 Pb/Se stoichiometry is favored when the stirring

speed is 1100 r.p.m.




215

[ NSN-60 ] Radial Breathing Modes and optical

properties in Ti Nanoparticles obtained by green

synthesis

Ricardo Andrés Britto Hurtado ([email protected]) 1 , Ramón Alexis Alvarez

Bayona 1 , Manuel Cortez Valadez 1 , Mario Flores Acosta 1 , Humberto Arizpe Chavez 1

1 Universidad de Sonora

In this research, we present the results of experimental and theoretical study of nanoparticles

of titanium (Ti) as the main reducing agent using the plant extract of Nopal (Opuntia ficus-

indica) to synthesize metal nanoparticles. Optical absorption, Raman spectroscopy, EDS,

TEM was used for characterization. Absorption bands located at 395 and 355 nm was

detected after reduction of the titanium ions. Nanoparticles with an amorphous structure were

visualized with a size less than 10 nm in diameter, on the other hand, nano crystal structures

were formed with sizes of 1-4 nm. The presence of Ti in the particles was confirmed by EDS.

It was found that the Raman spectrum shows bands at low wave numbers of 359 and 404

centered cm-1. Vibrational properties of Tin clusters (n = 2-13) using the theory of density

functional DFT were used, finding radial breathing modes in each cluster between 387-298

cm-1. The calculations used in the level of B3LYP approach in combination with the

LANL2DZ basis set.

[ NSN-69 ] AFM study of epitaxial layers grown from In-

As liquid phases on the isoperiodical GaAs and InGaP

substrates

Edith Guadalupe Castillo Baldivia ([email protected]) 1 , Andrei Yu. Gorbatchev 1

, Viatcheslav A. Mishurnyi, 1 , Francisco Javier De Anda Salazar 1 , Ulises Zavala Moran


1 UASLP-IICO

In a previous work [1] it has been shown that Liquid Phase Epitaxy (LPE) can be used to

grow quantum dots if there is a lattice mismatch between the epitaxial layer and substrate

and if the growth conditions lie far outside the thermodynamic equilibrium because of the

generation of elastic energy due to stress in the epitaxial layers[2]. But the thermodynamic

equilibrium in the liquid-solid interface is determined as well by the difference in chemical

compositions between the solid and liquid phases.




216

The objective of this work is to study the morphology of lattice matched LPE layers grown

simultaneously, from a single InAs liquid phase, on substrates with different compositions:

GaAs and InGaP/GaAs. The growth experiments were done at a liquidus temperature of

450°C with a supercooling of 6°C. Contact times were 1, 5 and 15 seconds.

Samples were characterized by Atomic Force Microscopy (AFM). Every epitaxial layers

surface contains nanoislands whose of heights and diameters are in the range of 2-65 nm

depending on the growth time and on the substrate kind. For the same experiment, the

nanoislands average sizes are larger when grown on InGaP and have higher densities and

rougher surfaces as compared to the nanoislands grown on GaAs. But the nanoislands grown

on GaAs substrates have more uniform distributions of heights and diameters. Furthermore,

it is convenient to mention ripples that appear on the surface of the epitaxial layer grown on

InGaP with 5 seconds the ripples are parallel to [0-11]. These studies allow us to conclude

that in the case of growth of low dimensional structures by LPE their properties are

determined by the magnitude of the thermodynamic disequilibrium that includes not only the

effect of the elastic energy generated by the mismatch between the epitaxial layer and the

substrate but also by the difference in the chemical compositions in the interface liquid-solid.

[1]Journal of Physics: Conference Series 167(2009) 012002

[2]Journal of Crystal Growth 57 (1982) 84-90

[ NSN-70 ] FeSe2 nanoparticles using hydrothermal

method: Structural, morphological and optical

characterization

M.V. Morales Gallardo ([email protected]) 1 , N.R Mathews

([email protected]) 1 , A.M Ayala 1 , M. Pal 2

1 Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Temixco,

Morelos 62580, México 2 Instituto de Física, BUAP, Av. San Claudio y Blvd. 18 Sur Col. San Manuel, Ciudad

Universitaria, C.P. 72570, Puebla, México

Iron pyrite is a nontoxic and earth abundant material which has wide applications in the fields

such as, thin film solar cells, photoelectrochemical cells, and photocatalysis. An optical band

gap of about 1 eV and the high absorption coefficient of 105 cm-1 make this material suitable

for the above mentioned applications. The work was focused on the development of phase

pure FeS2 nanoparticles by hydrothermal synthesis. The chemicals used were FeSO4 as a

precursor of Fe and Na2S2O3 as a source of sulfur (S) using water as the only solvent. The

crystallization process of the material was studied by annealing at different temperatures in




217

N2 atmosphere. Finally, it was concluded that thermal treatment at a temperature of 280 °C

for 3 h in N2 was the most appropriate condition to obtain pure pyrite. The product was

characterized by X-ray diffraction (XRD); the structural studies showed the formation of

phase pure FeS2 which was further confirmed by Raman spectrum. Morphological

characterization by scanning electron microscopy (SEM) showed the formation of compact

rod like structure. The estimated band gap energy was of 1.7 eV which is higher than the bulk

FeS2 (0.9 eV). The work for the development of thin films using these nanoparticles is under

progress and the structural and optical properties of the films will be discussed.

Acknowledgements: Authors acknowledge María Luisa Ramón García for the XRD analysis

and José Campos for technical support in material characterization This work was supported

by the project: CONACYT Ciencia Basica 238869, IN107815, CeMIE-Sol P28

[ NSN-78 ] Effect of rapid thermal annealing ambient of

SRO films obtained by hfcvd

Angel Mena ([email protected]) 1 , Godofredo Garcia

([email protected]) 1 , Tomas Diaz 1

1 CIDS-BUAP

Photoluminescent and vibrational properties of SiOx films deposited on crystalline silicon

sustrates (100) and annealed in a rapid thermal annealing (RTA) process are reported in this

work. The films were deposited by the Hot Filament Chemical Vapor Deposition (HFCVD)

technique, using molecular hydrogen (H2) and a fused quartz rod (SiO2) as a solid source.

The filament-source distance was keeped constant at 2mm in all process. Source-substrate

distance was adjusted at 1, 2, 3, 4 and 5mm. The characteristic peaks of the before annealing

SiOx films; stretching, bending and rocking, observed by FTIR spectroscopy showing a

dependence of the position with the growth temperature. The photoluminiscence peaks show

the best intensity around 750nm. After annealing in RTA hydrogen atmosphere at 900oC the

FTIR peaks remain almost the same, but the photoluminscence spectra shows a width

increase for about twice that the original sample the first in 750nm and second in 690nm The

deconvolution of the photoluminiscence spectra shows two principal peaks, one of them

remain in the same wavelenght in all cases 750nm, and the other presents a shift to short

wavelengths 660nm. This phenomena is attributed to creation of nanocrystals and radiative

defects in the SiOx films, the formation process of nanocrystals during the RTA appear to

be depending of the film density.




218

[ NSN-89 ] Synthesis, characterization and simulation of

copper oxide nanoparticles.

J.I. Valencia-Lima ([email protected]) 3 , E. Rubio-Rosas 1 ,

M.A. Morales-Sanchez 2 , R. Agustín-Serrano 1

1 Centro Universitario de Vinculación y Transferencia de Tecnología, Benemérita

Universidad Autónoma de Puebla. Av. San Claudio y 18 sur C.U. Col. San Manuel, C. P.

72570. Puebla, Pué. México. 2 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla. Av. San

Claudio y 18 sur C.U. Col. San Manuel, C. P. 72570. Puebla, Pué. México 3 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla. Av. San

Claudio y 18 sur C.U. Col. San Manuel, C. P. 72570. Puebla, Pué. México.

Copper oxide nanoparticles, using copper acetate and sodium hydroxide as precursors,

polyvinylpyrrolidone as surfactant and ascorbic acid as reducing agent in aqueous solutions,

were synthesized. A drawback in the synthesis of such nanoparticles is due to it operates at

a nanoscale, their morphology and size are difficult to handle; since a small increase /

decrease in temperature or concentration can generate big changes. Therefore, a

mathematical model from the reaction kinetics taking place in the synthesis is proposed. The

model control parameters can create an appreciation of parameters to be varied to obtain

morphology and specific particle size. The nanoparticles were characterized by X-ray

diffraction and scanning electron microscopy, showing a cubic crystal habit and particle size

within 100 nm. Testing their antibacterial activity by incorporating them into hydroxyapatite

as a biomaterial in bone filling is of particular concern. The impregnated hydroxyapatite

showed antimicrobial properties, offering an excellent inhibition zone.

[1] D. Yu, V.W. Yam, J. Am. Chem. Soc. 126 (2004) 13200.

[2] Y. Zhao, J.J. Zhu, J.M. Hong, N. Bian, H.Y. Chen, Eur. J. Inorg. Chem. 20 (2004) 4072.

[3] A.Kaminaga,V.K Vanag and I.R. Epstein, J.Phys. Chem. 122,174706(2005)

[4] I.R Epstein, I. Lengyel, S. Kadar, M. Kagan and M. Yokoyama(1992) "New Systems for

Pattern formation studies." Phys. A 188,26-33




219

[ NSN-95 ] Application of Silver Nanowire to Cotton

Fabric for Develop a Superhydrophobic Textile

Josefina Aguila Lopez ([email protected]) 3 , Alejandro

Rodríguez Juárez 4 , José Fernando Huerta Rosas 2 , José Ángel Juárez

Torres 2 , Jesús Antonio Fuentes García 4 , José Luis Herrera Pérez 4 , José

Francisco Sánchez Ramírez ([email protected]) 1

1 CIBA-Instituto Politécnico Nacional. San Juan Molino Km 1.5 de la Carretera Estatal

Sta. Inés Tecuexcomac-Tepetitla, Tlaxcala, 90700. México. [email protected] 2 Facultad de Ingeniería, Ingeniería Textil, Benemérita Universidad Autónoma de Puebla,

Puebla, 72570, México. 3 Instituto Tecnológico Superior de Tlaxco, Predio Cristo Rey Ex Hacienda de Xalostoc s/n

Carretera Apizaco Tlaxco Km. 16.8 C.P.90250 Tlaxco Tlaxcala, México 4 UPIITA-Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2580. Barrio

Laguna Ticoman 07340. México D. F.

We present a facile and effective method to prepared superhydrophobic cotton textile. Silver

nanowire were synthesized by a polyol process and then were conformal coated onto

individual cotton fibers through a simple dip and dry process. SEM images revealed a thin

and uniform silver nanowires coating on the cotton microfibers which was supported by a

surface chemical analysis by EDS. Further modification of the nanowire-containing cotton

textile with octyltriethoxysilane led to hydrophobic surface. Surfaces prepared showed a

sticky property, which exhibits a static water contact angle of ˃ 150° for a 10 µl droplet that

water drop did not slid off even when the sample was held upside down. These modified

cotton textiles are potentially useful in a wide variety of applications.

The authors are thankful to the Mexican Agencies, CONACYT, SIP-IPN and COFAA-IPN

for financial Supports.




220

[ NSN-114 ] Preparation and characterization of porous

anodic aluminum oxide films for solar thermal

applications

Samuel Santiago Cruz ([email protected]) 1 , Julio Rodríguez González 2 , Eduardo Mercado Aguilar 2 , Arturo Fernández Madrigal 1

1 Instituto de Energias Renovables Universidad Nacional Autonoma de México, Privada

Xochicalco S/N Temixco, Mor, México C.P. 62580 2 Universiad Tecnológica de Huejotzingo Camino Real a San Mateo S/N Santa Ana

Xalmimilulco Huejotzingo, Pue, México C.P. 74169

Porous anodic aluminum oxide films on substrates aluminum 1050 (99.5% Al) were

produced by anodizing with Direct Current Voltage (DCV), in phosphoric acid 2 M, the

potential was varied from 15 to 30 DCV. Time and temperature were kept constantly at 20

minutes and 18oC respectively. The anodized potential effects in transversal and surface

parameters of the films was studied by scanning electron microscopy (SEM), SEM

micrographs revealed film thickness between 670 and 1200 nm, 35-65 nm pore

diameters and barrier layer thickness of 25 and 35 nm on average. According to the current

vs. time graph, it was possible to observe four states in pore formation and porous film

formation. After the anodizing process, an increase in the oxygen content was observed due

to the formation of aluminum oxide on the surface of the substrate. Before the anodizing

process, the maximum diffraction peak corresponded to the plane (220), however, after the

process the maximum diffraction peak was seen as (111). The Porous anodic aluminum

oxide films could be used as selective absorber coatings in solar thermal applications with

the parameters observed, when nickel nanoparticles are electrodeposited at the bottom of the

pores by use an alternating current (AC).




221

[ NSN-122 ] Comparison of two morphologies base on

TiO2 according to its photocatalytic activity

José Alberto Isidoro Olvera Rodríguez ([email protected]) 1 , Carlos

Guzman Martinez 1 , Eduardo Arturo Elizalde Peña 1 , Karen Esquivel Escalante


1 UAQ

Nowadays the wastewaters are an important issue, especially the water polluted with

drugs. When the wastewater is treated, the traditional methods are not enough, because they

may cause that the pharmaceutical pollutants react with the chemicals added for the

decontamination process, and the obtained products could be even more lethal to the human

being.

The solution for this problem is the use of advanced oxidation processes, especially

the photocatalysis with TiO2. The purpose of this investigation is to change the morphology

of the TiO2, to determine if the morphology of the material has a significant role in the

treatment of wastewaters.

The nanoparticle of TiO2 was obtained through sol-gel synthesis, and to obtain the

nanotube structure, this was carried out by alkaline hydrothermal reduction assisted by

microwave process. The characterization of the material was made by TEM, S-BET, Raman

Spectroscopy and diffuse reflectance.

Results

According to the TEM micrograph was possible to achieve the change of the

morphology, obtaining from crystalline TiO2 nanoparticles, TiO2 nanotubes, Those can be

observed however is not homogeneous the formation and distribution of this structure. The

synthesis method must be improved in order to obtain the desired structure and distribution.




222

[ NSN-124 ] Self-organized TiO2 nanotubes

functionalized with iron oxide nanoparticles: Effect of

annealing and the concentration of iron in the precursor

solutions

Geraldine Hernandez ([email protected]) 2 ,

Wilson Lopera 2 , Maria Elena Gomez 2 , Walter Torres 1

1 Department of Chemistry, Universidad del Valle, Cali, Colombia 2 Department of physics, Universidad del Valle, Cali, Colombia

When activated by UV light, TiO2, a common semiconducting material, is used as a

photocatalyst for the degradation of organic compounds and the water splitting

reaction. Nanostructuring TiO2, in the form of nanotubes, for instance, significantly improves

surface area, which in turn enhances the oxide catalytic activity. For the last 30 years,

strategies to activate TiO2 with visible light have been implemented that aim at decreasing

the energy band gap between the valence and conduction band of TiO2 and preventing the

recombination of photo-generated electrons and holes in the material. While narrowing of

the band gap has been achieved by doping TiO2 with selected cations and anions, the issue

of prevention of electron-hole recombination has been addressed by the synthesis of hybrid

materials between TiO2 and other oxides, for instance, Fe2O3, in which the photo-generated

electrons and holes can be spatially separated.

Although heterojunctions between TiO2 nanotubes and Fe2O3 have been produced by

chemical and electrochemical means, a typical problem is that the interface between the two

oxides is not well defined. In this work, we report a novel electrochemical approach for the

preparation of hematite, a-Fe2O3 rods inside TiO2 nanotube films electrochemically

deposited on Ti electrodes. The structural and morphological properties of the Fe-

TiO2 nanohybrids are characterized by X-Ray diffraction and high-resolution-scanning-

electron and atomic-force microscopies as a function of the electrosynthesis variables and

annealing temperatures.

Acknowledge: This research was sponsored by research project No 1106569331046, C.I

7917 COLCIENCIAS-UNIVALLE; Center of Excellence on Novel Materials "CENM".




223

[ NSN-144 ] Synthesis and characterization of zinc

cobaltite nanostructures in low concentrations of

dodecylamine

Juan Pablo Morán Lázaro ([email protected]) 1 , Florentino

López Urías 4 , Oscar Blanco Alonso 3 , Verónica María Rodríguez

Betancourtt 5 , Israel Ceja Andrade 3 , Alejandra Carréon Alvarez 2 , Rocío

Castañeda Valderrama 2 , Marciano Sánchez Tizapa 2 , Amaury Suárez

Gómez 2

1 Departamento de Ciencias Computacionales e Ingeniería, CUValles, Universidad de

Guadalajara, Carretera Guadalajara-Ameca Km. 45.5, Ameca, Jalisco 46600, México. 2 Departamento de Ciencias Naturales y Exactas, CUValles, Universidad de Guadalajara,

Carretera Guadalajara-Ameca Km. 45.5, Ameca, Jalisco 46600, México. 3 Departamento de Física, CUCEI, Universidad de Guadalajara, Jalisco 44410, México.

4 Departamento de Materiales Avanzados, IPICYT, Camino a la Presa San José 2055, Col.

Lomas 4a sección, San Luis Potosí, S.L.P. 78216, México. 5 Departamento de Química, CUCEI, Universidad de Guadalajara, Jalisco 44410, México.

Zinc cobaltite (ZnCo2O4) is a p-type semiconductor material with spinel-type structure which

has been mainly used as electrode for Li-ion batteries and supercapacitors due to its higher

electrochemical performances and higher conductivities. In this work, ZnCo2O4

nanostructures have been prepared by a simple microwave-assisted colloidal method, using

zinc nitrate, cobalt nitrate and dodecylamine, dissolved in ethyl alcohol. The solvent

evaporation was made by applying microwave radiation at low power (~ 147 W). Various

concentrations of dodecylamine were used to control the surface morphology of ZnCo2O4

powders. Micro-rods (length of 20-40 µm), porosity (pore of ~ 2 µm) and semispherical

particles (diameter of ~ 0.42 µm) were observed by SEM, when 1, 2, and 3 g of dodecylamine

were used, respectively. While, nanoparticles were confirmed by TEM. X-ray powder

diffraction measurements indicated the formation of spinel compound ZnCo2O4 at a

calcination temperature of 800 °C. Five vibrational modes were acquired by Raman

spectroscopy and the main absorption bands were registered by UV-Vis spectroscopy. These

last measurements confirmed the formation of the ZnCo2O4 phase.




224

[ NSN-148 ] Polymethylmethacrylate (PMMA) fibers

reinforced with carbon nanotubes obtained by the

electrospinning technique

Rosa Yetzira Ponce Cano ([email protected]) 1 , Jorge R. Aguilar

Hernández 1 , María de los Ángeles Hernández Pérez 2

1 Escuela Superior de Física y Matemáticas - I.P.N., Edificio No. 9 U.P.A.L.M., Lindavista

C.P. 07738 México D. F. 2 Escuela Superior de Ingeniería Química e Industrias Extractivas - I.P.N., Edificio No. 8

U.P.A.L.M., Lindavista C.P. 07738 México D. F.

In this paper we present results concerning the manufacture of polymethylmethacrylate

(PMMA) fibers reinforced with carbon nanotubes, obtained by electrospinning from

polymers in solution. Electrospinning involves a potential difference of the order of 15 kV

or more, applied between a metal needle, which contains a polymer solution, and the collector

consisting of a copper plate. Continuos increase of the potential difference between the

electrodes will overcome the surface tension thereby expelling a fiber which is deposited on

the collector surface. In this work we obtained PMMA fibers 15% weight by appliying a

potential difference of 15 kV for a distance of 7 cm between electrodes. Moreover, another

pair of parameters, such as the type of solvent and the concentration of the solution, were

also varied. For the characterization of the fibers scanning electron microscopy, Raman

spectroscopy and FTIR spectroscopy were used. The results of this work showes that carbon

nanotubes were added in an ordered way, mostly perpendicular to the cross section of the

PMMA fibers.




225

[ NSN-155 ] CHARACTERIZING THE DOSIMETRIC

PROPERTIES OF ZnO UNDOPED AND DOPED

WITH Tb

Alejandro Ortiz Morales 1 , Epifanio Cruz Zaragoza 2 , Manuel García

Hipolito 3 , Ramón Gomez Aguilar 1

1 Instituto Politécnico Nacional, UPIITA, Av. IPN, No. 2580 Col. La Laguna Ticomán,

Gustavo A. Madero. México, D.F., C.P. 07340 2 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543,

04510 México D.F., México 3 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,,

04510, México D. F., México

It is well known that zinc oxide (ZnO) presents dosimetric properties when it is exposed to

ionizing radiation. This work reports some dosimetric properties of a new batch of Tb-doped

ZnO samples. This material was prepared by a spray pyrolysis (SPM) method. The

morphologic characterization of the samples was analyzed by Scanning Electron Microscopy

(SEM). The dosimetric properties such as: linearity on the function of the gamma doses, f(D)

and g(D) indexes and superlinearity, and the effect of heating rate (2°C/s – 40°C/s ) on the

ZnO were investigated. The linear response was between 0.5 kGy and 4 kGy. Also the

loosing of thermoluminescent response or fading up to 120 days was analyzed. The glow

curves during the fading decay were analyzed by the Glow Curve Deconvolution method

(CGCD) based on the mixed order kinetic to obtain the kinetics parameters.




226

[ NSN-158 ] Core-Shell Magnetite-ZnO synthesis assited

by sonochemistry

Ramon Rodriguez Lopez ([email protected]) 2 , Karen Esquivel

Escalante ([email protected]) 2 , Carlos Guzman Martinez 2 ,

Luis Antonio Ortiz Frade 1 , Eduardo Arturo Elizalde Peña 2

1 CIDETEQ 2 UAQ

The photocatalytic technology is an easy and cheap method for the treatment of organic and

inorganic non-biodegradable pollutants in the wastewater. The synthesis of a photocatalytic

material magnetically separable for its reutilization, can be done through a core-shell

structure, using a magnetite core (Fe3O4) for its magnetic properties and photocatalytic zinc

oxide (ZnO) as shell. Sonochemistry is used for the synthesis of the core-shell structure, using

magnetite synthetized by coprecipitation method, and ZnO nanoparticles by precipitation

method.

As a results of using sonochemistry for 20 minutes at 50% of power, 20 % of amplitude and

80% of cycles was possible to achieve a core shell structure, TEM results shown hexagonal

shape nanoparticles with a dark core and a shell surrounding that core, verifying the core-

shell structure.

According to these results the next stage is to carry out the photocatalysis test at pH 7 to

remove a textile dye expecting to have a good removal of it and a recovery of the catalyst by

a magnetic field.




227

[ NSN-163 ] Graphene growth from a pattern of pencil

drawn dots

Juan Jesus Vivas Castro ([email protected]) 1 , Gabriela

Lourdes Rueda Morales 1 , Jaime Ortiz Lopez 1 , Gerardo Ortega Cervantez

1

1 ESFM-IPN

We present a simple, economical and efficient way to synthesize single and double layer

graphene. Various patterns of equidistant dots were drawn with a commercial pencil on a Cu

substrate. Substrates with pencil outlined patterns are heated for 15 minutes at 1050 ° C in a

cylindrical oven under a flow of an Argon / Hydrogen gas mixture. From the results it was

observed that the number of layers, coverage and structural quality of the synthesized

graphene are closely related to the amount and distribution of the drawn patterns. The

samples were characterized by scanning electron microscopy and Raman spectroscopy. Our

findings show that graphite pencil lead can be used directly as a solid feedstock for high

quality graphene growth.




228

[ NSN-170 ] Characterization and application of Au

nanostructured substrates for surface enhanced Raman

spectroscopy using Methylene blue as a test molecule.

José Guadalupe Morales Méndez ([email protected]) 3 , Luis

Escobar Alarcón 2 , Emmanuel Haro Poniatowski 1

1 1UAM- Izt Physics Department, San Rafael Atlixco No. 186, Col. Vicentina, Iztapalapa,

09340, Mexico 2 ININ, Carretera Mexico- Toluca s/ n, La Marquesa Ocoyoacac, Mexico

3 UAM- Izt Physics Department, San Rafael Atlixco No. 186, Col. Vicentina, Iztapalapa,

09340, Mexico

The influence of the morphology and distribution of nano-structured gold substrates on the

localized surface plasmon resonance wavelength and surface enhanced Raman signal

(SERS) is investigated. The gold (Au) nanostructures are synthesized by laser ablation using

a Nd: YAG laser emitting in the third harmonic, at a wavelength of 355 nm. Nanostructures

are made by varying the number of pulses (600, 700, 800, 900, 1000, 1100, 1200, 1300, 1500,

5000) on the target. Typical pulse duration is 8 ns, the energy density is approximately 0.1

J/cm2. The gold nanostructures are characterized by UV- Vis spectroscopy. The surface

plasmon wavelength shows a strong dependence on the nanostructures morphology which

evolves progressively from nanospheres to more complex shapes. The SERS studies were

performed using methylene blue as test molecule. It is found that the SERS signal exhibits a

maximun depending on the surface morphology.

[ NSN-171 ] Synthesis, characterization and matematical-

molecular modelling of silver NPs by photocatalytic

reduction

M. A. De la Cruz Garcia ([email protected]) 3 , M. A. Morales

Sánchez 4 , E. Rubio Rosas 1 , J. Varela Caselis 1 , R. Agustín Serrano 1 , A.

Maldonado 2


Universidad Autónoma de Puebla, AV. San Claudio y Prolongación de la 24 sur, Col. San

Manuel C.P. 72570, Puebla Pué. México. 2 Facultad de Ciencias Físico-Matemáticas, Benemérita Universidad Autónoma de Puebla,

Av. San Claudio, Col. San Manuel, C.P. 72570, Puebla Pue. México. 3 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, Av. San




229

Claudio, Col. San Manuel, C.P. 72570, Puebla Pué. México. 4 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, Av. San

Claudio,Col. San Manuel, C.P. 72570, Puebla Pué. México.

Silver nanoparticles were synthetized by photo-reduction using silver nitrate (AgNO3),

distilled water (H2O) and polyvinylpyrrolidone (PVP). The following solutions were

prepared: a first solution (S1) of silver nitrate with distilled water to 0.01M, the second

solution (S2) of silver nitrate, distilled water and polyvinylpyrrolidone to 0.1M, both

solutions were irradiated by light UV with wavelength of 254 nm and exposition time of 40

and 80 minutes, respectively. The results obtained by Scanning Electronic Microscopy

(SEM) showed cubic, thetrahedrical, and spherical morphologies for S1, and triangular

morphology for S2. Two synthesis routes were employed: the one (S1) was realized with

constant agitation, while in the second route over a substrate of SiO2 was synthesized silver

nanostructures. The morphologies obtained, are particles with size of 50-100 nm,

approximately. The analysis of X-Ray Diffraction showed the crystalline phases of metallic

silver. We propose a photo-reaction mechanism which complemente the time-dependent

Ginzburg-Landau equation with not conserved order parameter (TDGL), and it allowed us

to simulate by computer the cubic morphology by adjusting control parameters such as

temperature, chemical potential and mobility of the system, to understand the subjacent

mechanism of growth and nucleation of silver nanoparticles.

Keywords: Ginzburg-Landau equation, growth mechanism, coarsening

1. Sato-Berrúet, al., “Silver nanoparticles synthesized by direct photoreduction of metal salts.

Application in surface-enhanced, Raman spectroscopy. 2009, 40, 376-380.

2. I. Ranvinoch, A. B. Ezersky, P. D. Weidman, The dinamics of patterns: World Scientific

Publishing Co. Pte. Lid, 2000.

3. Richards, G. H. “Computational chemistry”. New York: Oxford University Press.

4. Witkowski, A. Tiribocchi, J. Stenhammar, R.J. Allen, D. Marenduzzol, M. E. Cates,

“Scalar field theory for active particle phase separation”, Nature Communications. (2014)

DOI: 10.1038/ncomms5351.




230

[ NSN-181 ] Anomalous Transport in PT-Symmetric

Quarter Stacks

Josué Ramírez Hernández ([email protected]) 2 , Felix Izrailev

Mikhailovich 2 , Nykolay Makarov 1

1 Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Priv. 17 Norte No.

3417, Col. San Miguel Hueyotlipan, Puebla, Pue., 72050, México. 2 Instituto de Física de la Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla,

Pue., 72570, México.

We studied the transmission and reflection properties for a stack of 𝑁 bilayers with PT-

symmetry embedded in a homogeneous medium. Each (𝑎, 𝑏) bilayer is made of absorbing

electromagnetic energy material (layer 𝑎) and amplifying material (layer 𝑏). The losses and

gains are incorporated into the complex dielectric functions. They are balanced and their

strength is defined by dimensionless parameter 𝛾.

We have obtained a dispersion relation for the Bloch phase 𝜑𝐵 = 𝜅𝑑, which establishes the

dependence of the Bloch wave number 𝜅 on the wave frequency 𝜔 and loss/gain parameter 𝛾.

The spectral band/gap-structure appears only within an interval 0 < 𝛾 < 1. The number of

spectral bands 𝑁𝑏 turns out to be finite and to depend on 𝛾: the larger the loss/gain parameter,

the smaller the number of the spectral bands.

We have reviled that there are two mechanisms for emerging the perfect transmission 𝑇𝑁 =1 for a whole array of 𝑁 unit cells. The first one is the known Fabry-Perot resonances whose

number depends on the number of unit cells 𝑁 and the loss/gain parameter 𝛾. The second

mechanism is associated with two specific frequencies 𝜔𝑠𝑝 that separate the regions with

𝑇𝑁 < 1 from those with 𝑇𝑁 < 1 in every spectral band.

We have recognized that, whereas 𝑇𝑁(−𝛾) = 𝑇𝑁(𝛾) , the left-hand and right-

hand reflectances are transformed one to another as the sign of 𝛾 is changed, 𝑅𝑁(𝐿)(−𝛾) =

𝑅𝑁(𝑅)(𝛾) . In addition, they obey the relation 𝑅𝑁

(𝐿)(𝛾) ≤ 𝑅𝑁(𝑅)(𝛾) , being equal solely at

the Fabry-Perot resonances. At specific frequencies 𝜔𝑠𝑝 the effect of unidirectional

reflectionless emerges, where the perfect transmission 𝑇𝑁 = 1 takes place with vanishing

only the left-hand reflectance 𝑅𝑁(𝐿)(𝛾) = 0 . At the same time, the right-hand reflectance

conserves its finite and positive value, 𝑅𝑁(𝑅)(𝛾) > 0 . Our analytical findings are

demonstrated by numerical data.




231

[ NSN-185 ] Pd content effect on the degradation

efficiency in Pd/ZnO nanocomposites

Ma. De Lourdes Ruiz Peralta ([email protected]) 2 , Gustavo

Gonzalez Escobedo 2 , Alejandro Escobedo Morales 2 , J. Humberto

Camacho García 2 , Jenaro Varela Caselis 1


Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue., Mexico. 2 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, C.P.

72570 Puebla, Pue., Mexico.

In the present work, Pd/ZnO nanocomposites with various palladium contents were

prepared through hydrothermal method. The crystal structures, morphology and optical

properties of the nanocomposites were characterized by X-ray diffraction (XRD), SEM, UV-

vis, Fast Fourier Infrared (FT-IR) and micro-Raman spectroscopies.

Pd wt % were optimized to improve catalyst activity in the degradation of R6G used as a

representative dye pollutant, the results demonstrate a degradation efficiency of 98.9% with

a 1wt % of Palladium content.The pH value of the reaction mixture induces the formation of

Pd or PdO nanoparticles,Raman spectra of Pd/ZnO nanocomposites show a broad band at

640 cm-1, attributed at PdO formation, however, the Raman spectra of the nanocomposites

synthesized under acidic conditions shows a decrease in the intensity and a widening of the

E2 (high) mode.




232

[ NSN-193 ] Carbon Nanotubes Synthesis by Chemical

Vapor Deposition from Butanol, Diethyl Ether, Ethyl

Acetate and Hexane

Francisco Gabriel Granados Martínez ([email protected]) 3 ,

José de Jesús Contreras Navarrete 3 , Diana Litzajaya García Ruiz 3 ,

Carmen Judith Gutiérrez García 3 , Alejandro Durán Navarro 3 , Edgar

Eduardo Gama Ortega 3 , Nelly Flores Ramírez 3 , Lada Domratcheva

Lvova 3 , Leandro García González 1 , Luis Zamora Peredo 1 , María de

Lourdes Mondragón Sánchez 2

1 Centro de Investigaciones en Micro y Nanotecnología Universidad Veracruzana Calzada

Ruiz Cortines, 455, Costa Verde, 94294, Boca del Rio, Veracruz, México 2 Instituto Tecnológico de Morelia Av. Tecnológico 1500. Lomas de Santiaguito 58120,

Morelia, Michoacán, México 3 Universidad Michoacana de San Nicolás de Hidalgo Gral. Francisco J. Múgica S/N,

Felicitas del Río, 58030, Morelia, Michoacán, México

Sustainability has become a main focus in the synthesis of CNTs. The use of low toxicity

precursors has gain importance in order to reduce the environmental effects. The main object

of this research is to develop alternatives to current used carbon precursors in the production

of nanomaterials.

Carbon nanotubes were produced via chemical vapor deposition (CVD) using as carbon

source: butanol, diethyl ether, ethyl acetate and hexane. CVD was chosen due to its better

yield attributes and the versatility on the exploitable precursors; additionally, it offers more

control on the CNTs characteristics obtained. Argon was used as carrier gas at different flows

ranging from 50-90 ml/min. Samples were synthesized in catalytic reaction using a quartz

tube reactor and stainless steel AISI 304 core as catalyst support, at different temperatures

between 680-850 ºC, according to the precursor. CNTs were characterized through Scanning

Electron Microscopy (SEM), Energy Dispersed Spectroscopy (EDS), X-Ray Diffraction

(XRD), Fourier Transformed Infrared Spectroscopy (FTIR) and Raman Spectroscopy. The

SEM showed CNTs diameters from 50-300 nm. EDS analysis demonstrated carbon atomic

percentages ranging from 93-99 %, 1.0-4.5 % iron and less than 1 % of manganese, chrome

and silicon. FTIR confirms the presence of stretching vibrations containing CHx and C=C

typical of aromatic rings. The research proposed innovating CNTs synthesis throught the use

of some new carbon precursors and catalyst.

With the acknowledgment for the support on this research to the CIC-UMSNH projects and

the collaboration network of PRODEP “Nanostructural materials”.




233

[ NSN-205 ] MWCNTs oxidation by thermal treatment

with air conditions

Jose de Jesus Contreras Navarrete ([email protected]) 2 ,

Francisco Gabriel Granados Martínez 2 , Lada Domratcheva Lvova 2 , Nelly

Flores Ramírez 2 , María Remedios Cisneros Magaña 2 , Leandro García

González 3 , Luis Zamora Peredo 3 , María de Lourdes Mondragón Sánchez

1

1 Instituto Tecnológico de Morelia 2 Universidad Michoacana de San Nicolás de Hidalgo

3 Universidad Veracruzana

The incorporation of carbon nanotubes (CNTs) with several materials leads to new and

innovating applications; generally, a process of functionalization has to occur to achieve the

join. Nowadays the most different methods to add functionalized groups involve the use of

acids. These techniques implicate high costs, laborious multistep process and environmental

risks. The aim of this research was the oxidation of Multiwalled Carbon Nanotubes

(MWCNTs) at atmospheric conditions through thermal treatment adding carbonyl groups.

The MWCNTs were obtained by Chemical Vapor Deposition (CVD) at 760 °C using

benzene and ferrocene as organic and organometallic precursors and argon as carrier gas.

The MWCNTs were heated inside an electric furnace. Temperature ranged between 260 –

600 °C. The samples were characterized by Scanning Electron Microscopy (SEM), Energy

Dispersed Spectroscopy (EDS), X-Ray Diffraction, Fourier Transformed Infrared

Spectroscopy (FTIR) and Raman Spectroscopy. The results shown lost in weight percentage

that fluctuated from 0 to 78 % according to different temperature conditions. The SEM

micrographs indicated that MWCNTs remain below 400 °C. EDS analysis was focused in

single CNTs and clusters. Carbon nanotubes without thermal treatment contain only carbon

and iron; in contrast to the CNTs heated within air presence that showed up to 25 % oxygen.

The larger oxygen amount was found on CNTs extremes and for iron was on base. FTIR

analysis demonstrated presence of carbonyl groups and decrease of CHx. This research

proposes one step functionalize process with low costs and environmental risks for carbonyl

group CNTs.

With the acknowledgment for the support on this research to the CIC-UMSNH projects and

the collaboration network of PRODEP “Nanostructural materials”.




234

[ NSN-207 ] Optical properties of nanostructured

bimetallic hyperbolic metamaterials

Silvia Cortés-López ([email protected]) 1 , Felipe Pérez-Rodríguez 1

1 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Post. J-48,

Puebla, Pue. 72570, México.

The phenomenon of negative refraction, observed in metal-dielectric metamaterials, has been

widely studied. This phenomenon can occur in double negative metamaterials, whose

effective permittivity and permeability are simultaneously negative, or in strongly-chiral

metal-dielectric structures. Such negative index metamaterials are fabricated by using

different forms of the metal inclusions: split-ring resonators, dual-bar rods, fishnet structures,

rotated crosses, and so on. Nevertheless, the negative refraction can also be observed in

anisotropic media without requiring negative permeability nor strong chirality. For instance,

a metal-dielectric superlattice possesses negative index of refraction in the frequency interval

where the effective permittivity principal values, corresponding to the directions parallel and

perpendicular to the plane of the layers, have opposite signs. In this work, we consider

another type of superlattice, namely, a periodic heterostructure composed of two metallic

layers in the unit cell. We have calculated the components of the average permittivity tensor

in the long wavelength limit. Interestingly, the homogenized bimetallic superlattice behaves

as a uniaxial crystal with different frequency-dependent permittivities along and across the

periodicity direction. With these results, the reflectivity and transmissivity of a bimetallic

multilayer structure have been calculated too. For p-polarized electromagnetic waves, it was

found that both reflectivity and transmissivity exhibit Fabry-Perot resonances associated with

the quantization of the wave vector. The resonances are observed in the frequency interval,

where the refractive index is negative. We have analyzed the effect of both the bimetallic-

metamaterial slab thickness and the angle of incidence on the optical spectra of reflectivity

and transmissivity.

This work was partially supported by VIEP-BUAP and CONACYT.




235

[ NSN-209 ] Spectroscopic Characterization of Calcined

Zeolitic Tuff from Etla, Oaxaca-Mexico

Manuel Sánchez Viveros ([email protected]) 4 , Gregorio

Zacahua Tlacuatl ([email protected]) 4 , José Javier Castro Arellano 4 ,

Isaías Hernández Pérez 2 , Fernando Chávez Rivas 3 , Vitalii Petranovskii 1

1 Centro de Nanociencias y Nanotecnología, UNAM, C. P. 22860, Ensenada, B.C., México 2 Departamento de Ciencias Básicas, UAM-Azcapotzalco, C.P. 02200, México D. F.,

México 3 Departamento de Física, ESFM-IPN, C. P. 07738. México D.F., México

4 Laboratorio de Posgrado, ESIQIE-IPN. C. P. 07738, México D. F., México

This work reports studies of the nature of iron oxide species in zeolitic tuff from Etla, Oaxaca,

Méx. The zeolitic mineral has been grinding and calcined at 250 and 500 °C. The set of

samples were analyzed XRD, UV-Vis and EPR. As a catalytic test we have employed the

photo-catalytic degradation of Black 5 azo dye (RB5). By XRD technique was found an

increase of the initial amorphous phase, with increasing calcinations temperature, and the

analysis of selected diffraction lines and using the Debye-Scherrer function was found that

the average grain decrease mainly to the clinoptilolite phase. The UV-vis results shows that

the bands for λ > 650 nm decrease in intensity with the augmentation of the calcined

temperature, and the opposite effect is observed on the bands in the range of 400 to 650 nm.

Form EPR technique we have detected broad ferromagnetic signals characteristics of iron-

oxides nanoparticle, who´s intensity decrease with the calcinations temperature. Concerning

to the catalytic activity was found that the samples calcined at 500 °C have a better photo-

catalytic in comparison with the lower and the uncalcined samples. We propose to the iron

oxides nanoparticles as the sites of the photo-catalytic activity into the degradation of RB5.




236

[ NSN-225 ] Synthesis, characterization and simulation of

ternary magnetic fluids whit magnetite nanoparticles

Sergio Enrique Pichón Posada ([email protected]) 1 ,

Marco Antonio Morales Sánchez ([email protected]) 1

1 Benemérita Universidad Autónoma de Puebla (BUAP)

Keywords: magnetic fluid, magnetic nanoparticles, Hele-Shaw cell, magnetite, magnetic

field strength.

In the present work was realized the synthesis of a magnetic fluid made of magnetite

nanoparticles, these nanoparticles were suspended in oil and immersed in water with the aim

of understand the behavior of the ternary mixture in the presence of magnetic fields and create

a model mathematician to explain the mixture pattern formation. Magnetite nanoparticles

were obtained by the precipitation method of ferric and ferrous salts in solutions of

ammonium, obtaining nanoparticles of 70 nm. These nanoparticles were functionalized with

a coupling agent (3-Glycidyloxypropyl trimethoxysilano) in order to generate a better

compatibility and fluid dispersion. The nanoparticles were characterized by X-ray diffraction

(XRD), infrared spectroscopy (FTIR), electron microscopy (SEM), atomic force microscopy

(AFM) and to study the behavior of the magnetic fluid by optical microscopy. Finally, the

computer simulation (using Fast Fourier Transform with programming language python and

their libraryT-Kinter) of the mathematical model can to be controlled different parameters

such as concentration of particle magnetic moments, magnetic field strength, temperature

and chemical potential. The patterns obtained by this simulation are very similar to the

behavior shown experimentally, confirming the accuracy of the mathematical model

presented earlier.

References:

[1] M. A. Morales, J.F. Rojas: Modeling ternary mixtures by mean-fiel theory of polyelectrolytes:

coupled Ginzburg-Landau and Swift-Hohenberg equations, Benemérita Universidad Autónoma de

Puebla, Centro universitario de vinculación y transferencia tecnológica, Physica A 391 (2012) 779-

791.

[2] P.e. Lloret, C.a. Moina, G.o. y barra: síntesis, funcionalización y caracterización de nanoparticulas

magnéticas con estructura núcleo-cáscara, centro de investigación y desarrollo en electrodeposición

y procesos superficiales. (7 de septiembre 2007).

[3] Antonio Mora Rosas: Modelación y Simulación de Comportamientos No-lineales, en Física de

Materiales, Química y Biomimética, Benemérita Universidad Autónoma de Puebla. Centro

universitario de vinculación y transferencia tecnológica. Pág. 1-7.




237

[ NSN-279 ] Low-temperature thermal annealing of pure

Zn nanostructures

Roberto López ([email protected]) 1 , Enrique Vigueras 1

1 Laboratorio de Investigación y Desarrollo de Materiales Avanzados (LIDMA), Facultad

de Química, Universidad Autónoma del Estado de México, Paseo Colón esquina Paseo

Tollocan, Toluca Estado de México, México

Metal Zn nanostructures were deposited by vacuum thermal evaporation and subsequently

annealed in ambient atmosphere. The Zn nanostructures were deposited during 10, 30, or 60

min at a vacuum pressure of 10 -6 Torr. The nanostructures were then heated at 100 or 200

°C for several post-annealing times. Scanning electron microscope, energy dispersive

spectroscopy, and X-ray diffraction under grazing incidence techniques were performed to

evaluate the morphological and structural characteristics of the Zn nanostructures after the

thermal annealing process. The nanostructures heated at 100 °C held similar morphological

and structural characteristics compared to that of those as-deposited samples. However,

annealing performed at 200 °C leads to the transformation of the structure and morphology,

which changed the initial metal properties of the as-deposited nanostructures.




238

[ NSN-282 ] Growth of 4-aminothiophenol on iodine

modified Au(100) studied by scanning tunneling

microscopy

Tizoc Fernando Huerta Garcia ([email protected]) 2 , José

Valenzuela Benavides ([email protected]) 1


Km. 107 Carret. Tijuana-Ensenada, Ensenada, B.C., México c.p. 22860 2 Posgrado en Ciencia e Ingeniería de Materiales, U.N.A.M. Km. 107 Carret. Tijuana-

Ensenada, Ensenada, B.C., México c.p. 22860

Abstract:

The presence of an adsorbed iodine layer on different crystallographic faces of noble metals

can reduce the interaction strength between an adsorbed organic molecule and the metal

substrate, permitting the weaker intermolecular interaction to become relevant thus resulting

in long range order in self assembled molecular (SAM) layers. In this work, we describe the

growth mechanism of 4-aminothiophenol (4-ATP) molecules on iodine modified Au(100),

as studied by electrochemical scanning tunneling microscopy and cyclic voltammetry. The

first stages of ATP adsorption is characterized by one dimensional molecular growth along

well defined directions of the iodine monolayer, and long and thin trenches between

molecular lines that are present even after several layers have grown. At more positive

potentials complete surface coverage is observed on the surface. After returning the potential

to more negative potentials, molecular desorption occurs and randomly distributed pits or

vacancies appear on the surface. This markedly different desorption mechanism from the

adsorption process is explained in terms of the different molecular bonds during the oxidation

of the ATP molecule. Although 4-ATP oxidation and the formation of secondary products

on a Au electrode is a rather well studied process, to our knowledge the present work

represents the first attempt to understand the role of an iodine monolayer on the

electrochemistry of ATP on Au(100) electrodes.

Keywords: Scanning tunneling microscopy, electrochemical phenomena, gold, iodine,

aminothiophenol




239

[ NSN-302 ] Adsorption of methylene blue dye onto

multiwalled carbon nanotubes decorated with metal

nanoparticles

Julián López-Tinoco ([email protected]) 5 , Javier Lara-Romero 4 ,

Francisco Paraguay-Delgado 1 , Gabriel Alonso-Núñez 3 , Sergio Jiménez-Sandoval 2

1 Centro de Investigación en Materiales Avanzados Unidad Chihuahua 2 Centro de Investigación y de Estudios Avanzados del IPN Unidad Querétaro

3 Centro de Nanociencias y Nanotecnologia UNAM Ensenada 4 Facultad de Ingeniería Química-Universidad Michoacana de San Nicolás de Hidalgo

5 Universidad Politécnica de Lázaro Cárdenas

Synthetic dyes are extensively used as coloring agents in textile, paper, pharmaceutical and

food industries. Water contamination with these synthetic dyes is a serious environmental

problem. In this work we evaluate the adsorption capabilities of ceria and zirconia

nanoparticles deposited on multiwalled carbon nanotubes as an alternative to the adsorption

of dyes.

The dye used in this study was the basic blue 9 (Methylene Blue). The adsorption studies

were carried out using UV-Vis spectroscopy. It was found that carbon nanotubes with ceria

and zirconia nanoparticles have a greater adsorption capacity compared to functionalized

CNTs.

For the synthesis of the metal nanoparticles, metal nitrates were used as metal sources, dioctil

sodium sulfosuccinate (AOT) was used as surfactant and NaBH4 was used as a reducing

agent. The synthesis was performed at 120°C, 10 minutes and 600 W. Carbon nanotubes

multiwalled were synthesized by the spray pyrolysis method using alpha-pinene as a carbon

source and ferrocene as catalyst. CNTs were purified and functionalized by a conventional

acid treatment. The materials produced were characterized by transmission electron

microscope of high resolution (HR-TEM), Raman spectroscopy, thermal gravimetric

analysis (TGA) and X-ray diffraction (XRD).




240

[ NSN-304 ] Optical properties for dielectric-graphene-

dielectric multilayer quasi-periodic Thue-Morse

Structure

Ireri Aydee Sustaita-Torres ([email protected]) 2 , Claudia

Sifuentes-Gallardo 2 , Raúl Alberto Reyes-Villagrana 1 , Isaac Rodríguez-

Vargas 1 , Jesús Madrigal-Melchor ([email protected])

1

1 ) Unidad Académica de Física, Universidad Autónoma de Zacatecas, 98060, Zacatecas,

México. 2 Unidad Académica de Ingeniería Eléctrica, Universidad Autónoma de Zacatecas, 98000,

Zacatecas, México.

Potential applications in optoelectronics had generated a great interest of study of graphene

optical properties. Along with this, the graphene have exceptional properties such as high

mobility and optical transparency, flexibility, robustness. Is for this properties of graphene

can be used in different devices such as transparent conductors, organic light-emitting diodes,

photodetectors, touch screens, saturable absorbers and ultrafast lasers [1]. A transfer matrix

method (like Pochi-Yeh) is developed for obtained optical properties, reflection,

transmission, and absorption in the far-infrared region. The quasi-periodic structure was

compound by intercalate graphene sheets between two consecutives dielectrics, and the

dielectrics media follows Thue-Morse sequence. The graphene sheets was described by the

optical conductivity considering interband and intraband transitions [2]. The structure of the

spectra depends, in far infrared region, strongly of the number of sequence generation, width

of the different dielectrics and optical contrast (dielectric contrasts). The results for transverse

magnetic polarization and transverse electric polarization for different angles are shown. In

spectra the geometrical properties of the sequence Thue-Morse can be observed and obtain

absorption band well define. We had made a comparison between quasi-regular and regular

structures.

[1] F. Bonaccorso, Z. Sun, T. Hasan and A. C. Ferrari, Graphene photonics and

optoelectronics, Nature Photonics, 4 611-622, sep. (2010).

[2] L. A. Falkovsky and S. S. Pershoguba, Optical far-infrared properties of a graphene

monolayer and multilayer, Phys. Rev. B 76, 153410 (2007).




241

[ NSN-319 ] Different routes to prepare MoS2 nanofibers

by electrospinning, for applications in lithium ion

batteries.

Nadia Cruz Gonzalez ([email protected]) 1 , Miguel Angel Melendez

Lira 1

1 Department of Physics, CINVESTAV-IPN, Av. Instituto Politécnico Nacional 2508, col.

San Pedro Zacatenco, Delegación Gustavo A. Madero, México D.F. C.P. 07360

Recently, energy problem has become the greatest problems and attracted worldwide

attention. It has been proved to be an important task for scientist to search new materials

possessing great performances in dealing with the energy conversion, storage and usage.

Super capacitor is a new energy storage device, and it has many advantages such as long

service life, great power density, high energy density, green environmental protection and

has attracted enormous research interest. In recent years materials based on metal

dichalcogenides layered (MDL) has been used in anodes for the second generation of

rechargeable lithium batteries (LIBs) for its similar properties of graphene. The super

capacitor performance of MoS2 is comparable to those carbon nanotube array electrodes.

However, the electronic conductivity of MoS2 is still lower compared to graphite / graphene,

and the specific capacitance of MoS2 is still very limited in alone for energy storage

applications. Nanofibers-LMD / potentiate chemical and electrical properties of both

materials that absorb volume expansion in the loading / unloading, improving structural

stability and cyclability of the electrodes. This paper describes tow procedures of

synthesizing MoS2 nanofibers. In First method Polyvinylpyrrolidone (PVP)/Ammonium

tetrathiomolybdate (ATTM) composite nanofibers were prepared by a sol–gel method and

an electrospinning technique. Subsequently, the MoS2 nanofibers were derived from

reduction of these precursor composite fibers at 450 °C under a H2 atmosphere for 2 h, and

annealed under Ar atmosphere for 6 h. In Second Method, PVP nanofibers and MoS2

nanoribbons were synthetized bye electrospinning and solvothermal techniques. The

composite nanofibers were characterized by X-ray diffraction (XRD), Fourier transform

infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission

electron microscopy (TEM).

This work was financed by CONACYT project number CB2010-154857 and CONACYT

postdoctoral fellow second call 2014, Referencia: CVU No.218308.




242

[ NSN-324 ] Fractal graphene systems: Combined effects

of magnetic and electric fields on the transmission,

transport and electronic structure characteristics

Rogelio Rodríguez González ([email protected]) 1 , Isaac

Rodríguez Vargas 1

1 Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad

Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac., México.

We investigate the tunneling peculiarities of massive Dirac electrons through

magnetoelectric fractal graphene barriers. To this aim, the transmittance, linear-regime

conductance and spectrum of bound state are calculated. For the magnetoelectric fractal

barriers the electric and magnetic fields are considered along with a non-periodic order of

Cantor kind for the spatial distribution of the barriers. With this in mind, we compare the

above physical properties between systems of electric, magnetic and magnetoelectric

barriers. Our results indicate that the magnetoelectric barriers together with the aperiodic

order can modulate in an effective way the transmission, transport and electronic structure

characteristics.




243

[ NSN-364 ] Electrical transport properties of self-

Assembled ZnO nanoparticles embedded in a silicon

oxide matrix produced by reactive RF sputtering.*

P.R. Jiménez-Macías 1 , A. Lara-Sánchez 5 , A. Hernández-Hernández 4 , A.

García-Sotelo 3 , E. Campos 3 , S. Gallardo-Hernandez 3 , M. Zapata-Torres

2 , J.L. Fernández-Muñoz 2 , E. Valaguez-Velazquez 6 , M. Melendez-Lira ([email protected]) 1

1 1Departamento de Física, CINVESTAV-IPN, , Apdo. Postal 14-740, 07000, México DF 2 CICATA-IPN, Unidad Legaria, Calz. Legaria 694, Col. Irrigación, 11500, Mexico, DF 3 Departamento de Física, CINVESTAV-IPN, , Apdo. Postal 14-740, 07000, México, DF

4 Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo, Calle Ejido de

Chimalpa Tlalayote S/N Col. Chimalpa, Apan, Hidalgo. México 5 Facultad de Ingeniería, Universidad Autónoma de Chihuahua, México,

6 UPIITA-IPN Av. IPN 2580, C.P. 07340 México, DF

Self-assembled silicon and germanium nanoparticles embedded within a SiO2 matrix have

been successfully produced taking advantage of the roughness associated with the sputtering

deposition process[1,2].

The aforementioned approach has been employed to explore the possibility to produce ZnO

nanoparticles embedded within a silicon oxide matrix on soda-lime glass and p-silicon

substrates. Silicon dioxide and metallic Zn films were deposited employing silicon and zinc

targets. Oxygen content of the working plasma was modulated through argon partial

pressure. X-ray diffraction characterization do not shown the presence of metallic zinc.

Secondary ion mass spectroscopy shown an interdifussion of zinc throughout the SiO2

matrix. TEM micrographs indicated the presence of nanoparticles. XPS shown ZnO

formation under specific growth parameters. Photoluminescence emission at room

temperature for samples grown on silicon substrates was not observed. Transport properties

were studied measuring the IvsV characteristics of the films. For samples grown on silicon

rectifying behavior and spectral response are observed . The observed results of transport

properties are discussed in terms of the crystalline structure of the ZnO nanoparticles and its

interaction with SiO2 matrix.

*: Partially funded by CONACyT-Mexico

[1]. Mota-Pineda, E., et al. Journal of Applied Physics 108.9 (2010): 094323.

[2] Hernández-Hernández, A., et al. Journal of Applied Physics 111.4 (2012): 044327.




244

[ NSN-366 ] Nucleation and growth of eutectic

nanopowders: a re-engineering approach

H. Rojas-Chávez ([email protected]) 3 , D.A. Mora-Alvarado 3

, M.L. Mondragón-Sánchez 2 , C. Flores-Morales 4 , D. Jaramillo-Vigueras 1

1 Centro de Investigación e Innovación Tecnológica - IPN 2 Instituto Tecnológico de Morelia - TecNM

3 Instituto Tecnológico de Tláhuac II - TecNM 4 Instituto de Investigaciones en Materiales - UNAM

We report the mechanosynthesis of Pb0.26Sn0.74 nanoparticles using high-energy milling

process under composition, pressure and temperature (C-P-T) vial conditions.

A eutectic alloy was obtained by mechanosynthesis from elemental powders of Pb and Sn

via high-energy milling under controlled C-P-T vial conditions. Systematic analysis of

transformation in the resulting phases of milling has been envisaged to characterize

microstructures i.e. morphology, particle size and percentage of different phases formed as a

function of milling time. As-milled powders were analyzed by Atomic Force Microscopy,

X-ray powder diffraction and crystals structures were refined by the Rietveld method. The

results reveal that the system of Pb-Sn powders transforms gradually to eutectic alloy,

Pb0.26Sn0.74.

The difficulties in using the conventional process (melting/solidification) for producing

eutectic alloys lie in certain aspects. First, the temperature is usually quite high, which could

cause the oxidation of samples according to the Gibbs free energy criteria. Second, the poor

mixing in the liquid zone promotes segregation in melted alloys. The third problem is that

the conventional process use vacuum conditions and the surface oxides in melted alloys have

to be reduced by molecular hydrogen. So, this process is expensive compared with the

proposed one. In order to overcome these difficulties, we suggest a non-equilibrium process

as follows: this process utilizes an equivalent energy in order to ensure a free-impurities

stoichiometric eutectic alloy. Moreover, an inert experimental setup and a high-energy

mechanical source are suggested. Re-engineering of eutectic alloys obtained by a non-

equilibrium process to fully avoid thermal energy sources is proposed in this work.




245

[ NSN-388 ] Incorporation of ZnO Nanostructures in a

MIS Diode Architecture

Rubén Jonatan Aranda García ([email protected]) 1 , Daniel

Valdivia Montes 2 , Alejandro Escobedo Morales

([email protected]) 2 , Jose Alberto Luna López 1 , José

Antonio Rivera Márquez 2

1 Centro de Investigación en Dispositivos Semiconductores-ICUAP, Benemérita

Universidad Autónoma de Puebla, Puebla, Pue., Mexico 2 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, Puebla,

Pue., Mexico

Because of its physical properties, ZnO is considered a potential semiconductor compound

for fabricating electronic and optoelectronic devices. In this regard, several growth

techniques have been developed to ensure the required control for manufacturing commercial

devices. On the pathway for improving the performance of the actual devices, low-

dimensional materials seem to be a promising alternative.

Here, the fabrication of a metal-insulator-semiconductor (MIS) diode structure based on ZnO

nanostructures is reported. The ZnO nanostructures were grown on anodized aluminum

substrates (Al2O3/Al). While the ZnO nanostructures were obtained through a low-

temperature hydrothermal route, the substrates were prepared by subsequent electrochemical

processes: electropolishing (4V; 8 min) and anodizing (1 mA; 2 min). The ZnO/Al2O3/Al

architecture was studied by x-ray diffraction (XRD), scanning electron microscopy/energy

dispersive x-ray spectroscopy (SEM/EDS) and impedance measurements. The voltage-time

data (anodizing) and the capacitance values indicate the formation of an insulating barrier

(Al2O3) on the metallic substrate (Al); this was confirmed by means of SEM and EDS

analysis. Our studies show that the reported method is effective for growing ZnO nanorods -

whose dimensions are about a hundred nanometers- on anodized aluminum substrates in

order to obtain a MIS diode structure. The ZnO nanostructures have preferred orientation,

presumably along the [001] direction as their crystal habit suggests.




246

[ NSN-389 ] Physical and magnetic properties of

nanostructured Gd-Fe3O4 cores obtained by co-

precipitation

Sandra Irene Eguía Eguía ([email protected]) 2 , Angel Guillén

Cervantes 1 , Jaime Santoyo Salazar 1

1 Departamento de Física, CINVESTAV Zacatenco, México, D.F. 2 Doctorado en Nanociencias y Nanotecnología, CINVESTAV Zacatenco, México, D.F.

Nowadays, iron oxides doped with Gd nanoparticles have been investigated due to their

superparamagnetic properties as directional magnetic core in bio-medical applications. The

main challenge is synthesize Gd-Fe3O4 nanoparticles with magnetic monodomains and

uniaxial anisotropy with low remanence energy. These features allow getting specific control

over magnetic response and biodistribution for future applications as functionalized systems

in nanomedicine. In this work, we show preliminary results of the synthesis of Gd-Fe3O4

nanoparticles via co-precipitation of aqueous solutions of ferrous and ferric chloride salts.

The as-synthesized powders were characterized by different techniques. Size, morphology

and composition of the nanoparticles were determined by transmission electron microscopy

(TEM), scanning electron microscopy (SEM); and energy-dispersive x-ray spectroscopy

(EDS), while the structure of the as-synthesized nanoparticles was identified by x-ray

diffraction (XRD) and, Fourier transform infrared (FT-IR). Finally, these results are

correlated with magnetic responses and magnetic domains interactions measured by

magnetometer and magnetic force microscopy (MFM) to consider the Gd-Fe3O4 as candidate

for contrast agent and hyperthermia treatment applications.




247

[ NSN-399 ] Magnetic properties of nanostructured MBE

grown (GaMn)As

Antonio Del Rio De Santiago ([email protected]) 1 , Esteban Cruz Hernandez 1 ,

Cesar Fidel Sanchez Valdes 2 , Jose Luis Sanchez Llamazares 3 , Isaac Martinez

Veliz 4 , Maximo Lopez Lopez 4 , Victor Hugo Mendez Garcia 1

1 Center for the Innovation and Application of Science and Technology (CIACyT), Universidad

Autónoma de San Luis Potosí, Av. Sierra Leona #550, Lomas 2a Secc., San Luis Potosí, S. L. P.

78210, México. 2 CNyN, UNAM, AP 14, Ensenada 22860, Baja California, México.

3 Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José

2055, Col. Lomas 4ª sección,San Luis Potosí, S.L.P. 78216, México. 4 Physics Department, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal

14-740, México D.F. 07000, México.

The growth a semiconductor materials that sustain ferromagnetic properties at room temperature have

been the target of numerous studies since the Mid-20th century. The importance of these systems lays

on their potential applications in areas such as quantum computing, spintronics and novel solar cells.

The most promising materials among dilute magnetic semiconductors (DMS) to realize these

applications is the GaAs doped with Mn. Typically, the (GaMn)As films are grown by molecular

beam epitaxy (MBE) at low temperature (LT) (<290°C), due to the fact that the solubility of Mn in

GaAs is very low at thermal equilibrium, so that (GaMn)As is a metastable compound which can only

be grown with low temperature MBE far from thermal equilibrium. However, LT-MBE has several

disadvantages, such as high concentration of vacancies, interstitial Mn and As antisities. Most of these

factors limit the ferromagnetic transition temperature below 177K [1]. In this work in order to avoid

the above mentioned defects, we grew (GaMn)As by MBE at high temperature, 530 ° C. By using a

vibrating sample magnetometer, hysteresis loops in the range of temperature from 3 and 400 K were

obtained. The remanent field shows ferromagnetism above room temperature for samples grown at

the Mn concentration, Mn%, of 0.02 to 0.2. The coercive field at RT, Hc, increases from 52.85 to 356

Oe as Mn% increases. The remanent magnetization, M, shows a similar dependence with Mn%: it

steadily changes from 0.87×10-6 to 3.71×10-6 emu. However, for samples Mn%=0.02 and 0.04%,

dissimilar magnetic properties dependence was found. This is explained in terms of differences in

crystalline quality for these samples as corroborated by high resolution X-ray diffraction. To be sure

of the fact that the manganese is integrated in the whole layer, secondary ion mass spectrometry

(SIMS) depth profiles were obtained. The SIMS analysis indicates that, though the Mn%

incorporation was not uniform, the dopant is integrated into the entire layer.

[1] H. Ohno, A. Shen, F. Matsukura, A. Oiwa, A. Endo, S. Katsumoto, Y. Iye, Appl.Phys. Lett.

69 (1996) 363.

Acknowledgments: The author acknowledges the financial support of CONACYT, CeMIE-SOL 22,

FRCUASLP, INFR-2015-01: 255489, PNCPN2014-01: 248071, and CB: 168761.




248

[ NSN-409 ] Mn incorporation in GaAs grown by HT-

MBE studied by SIMS and HRXRD

Estebán Cruz Hernández ([email protected]) 1 , Antonio Del Río De

Santiago 1 , Salvador Gallardo Hernández 2 , Miguel Angel Vidal Borbolla 1

, José Angel Espinoza Figueroa 1 , Manuel Gutiérrez Hernández 1 , Máximo López López 2 , Víctor Hugo Méndez García 1

1 CIACyT, Universidad Autónoma de San Luis Potosí 2 Departamento de Física, CINVESTAV

Diluted Magnetic semiconductors (DMS) has received much attention in recent years due to

the interest in the integration of ferrogmanetism and spin-electronics with the ubiquitous

semiconductor technology [1]. In particular, the growth of the DMS GaMnAs exhibiting high

crystalline quality is of special interest to the incorporation of ferromagnetic GaMnAs layers

into the GaAs-based microelectronic and optoelectronic devices. However, these potential

applications has been limited because GaMnAs with useful Mn atomic percent (Mn%) high

concentration is only obtained by growing at low-temperature (< 300 °C), which cause a poor

GaMnAs crystallinity as compared with GaAs grown at higher temperatures (>500 °C). In

this work we investigate the mechanisms of the Mn incorporation in GaAs by growing by

MBE at the relative high temperature of 530 °C. The samples were grown by varying the

nominal Mn% from 0.01 to 0.2. From AFM and SEM imaging we found the formation of

nanostructures at the top of an initial layer of GaMnAs for the higher Mn% concentrations.

For Mn% < 0.1, nor any formation of surface structures was found. By SIMS analysis

variations in the Mn gradient concentration were obtained, which strongly depends on the

Mn% and the formation of the nanostructures. HDXRD rocking curves shows good

crystallinity and the apparition of MnAs aggregates in the sample with the higher Mn%

concentration.

*Corresponding author: [email protected]

[1] Rev. Mod. Phys., Vol. 86, No. 1, (2014)


SOL 22, FRC-UASLP, INFR-2015-01: 255489, PNCPN2014-01: 248071, and CB: 168761.




249

[ NSN-410 ] Influence of Dy doping on structural and

optical properties of ZnO nanostructures

Raul Sanchez Zeferino ([email protected]) 1 , Gemma

Moreno Corella 2 , Mario Enrique Álvarez Ramos 1 , Javier Hernández

Paredes 1

1 Departamento de Física, Universidad de Sonora, Blvd. Luis Encinas J y Rosales S/N Col.

Centro, Hermosillo, Sonora C.P. 83000, México. 2 Posgrado en nanotecnología, Universidad de Sonora, Blvd. Luis Encinas J y Rosales S/N

Col. Centro, Hermosillo, Sonora C.P. 83000, México.

The study of the optical properties of ZnO is an important research for practical applications

such as solar cell, gas sensors, white light emitting, optoelectronic devices, etc. Using

sonochemical synthesis, undoped ZnO and Dy-doped ZnO 1-4 mol % nanoparticles were

prepared. The aim of this work is to analyze the optical properties of ZnO nanostructures for

possible application in white light emitting devices. Scanning electron microscopy (SEM)

showed that undoped ZnO nanostructures have an undefined morphology, however, for the

Dy-doped ZnO nanostructures present a formation of leaves or flakes type morphology.

Patterns of X-ray diffraction (XRD) showed peaks assigned to the hexagonal wurtzite type

structure of ZnO in the case of heat-treated samples at 700 °C and majority phases of zinc

hydroxide for ZnO powders without annealing. The main vibrational modes of ZnO were

found in the Raman spectra performed on samples with annealing, however, for the samples

without annealing mainly phases of zinc hydroxide were found, it is consistent with the

results of XRD. The UV-Vis spectra exhibit an absorption edge around 383 nm which is

characteristic of ZnO. All the photoluminescence spectra (PL) of ZnO and ZnO: Dy

nanostructures showed two emission bands. A PL peak at approximately 383 nm and a broad

emission band between 400 and 800 nm. The results showed that the emission from the

sample without annealing and doped with Dy 2 mol % is the closest to the white light

emission. Several significant changes in the properties of ZnO:Dy were observed due to the

variation of doping and the application of annealing which are discussed in detail in this

research.




250

[ NSN-419 ] Effect of the applied external magnetic field

in the density of interfacial traps in nanometer

transistors

Hector Manuel Uribe Vargas ([email protected]) 1 , Joel Molina Reyes 1

1 INAOE

As the dimension of advanced electronic devices reach nanometric scales, high-k materials

are used as gate oxides in state-of-the-art Complementary Metal-Oxide-Semiconductor

(CMOS) devices. These oxides have allowed Moore´s law to continue, nevertheless, the

interface between high-k oxides and silicon does nos have good quality, thus reducing the

mobility of the electrons in the channnel, so its important to measure the denisty of interface

traps in these devices.

One often used technique to measure the interface trap density is C-V, altough this technique

can not be implemented in ultra-thin high k- oxides (<4nm). One alternative is the charge

pumping technique, which we used in this work.

In this work, 28nm IBM transistors were electrically charachterized (Id-Vg, Id-Vd, Vth, Vfb)

and using the charge pumping technique, Dit was measured in these devices. Then, an

external magnetic field perpendicular to the channel is applied, thus modulating the Dit.




251

[ NSN-432 ] Green synthesis of silver and gold

nanoparticles by aquoethanolic extract of Bacopa

procumbens (Mill.)

Valentin Lopez Gayou ([email protected]) 1 , Juan Manuel Castelan

Figueroa 1 , Elias Emilio Hernandez Beteta 1 , Marlon Rojas Lopez 1 ,

Alejandro Zamilpa 2 , Blanca Eda Dominguez Mendoza 3 , David Guillermo Perez Ishiwara 1

1 CIBA-IPN, Tlaxcala, 90700, Mexico 2 CIBIS-IMSS. Argentina No. 1, Col. Centro, Xochitepec, Morelos C.P. 62790, México

3 Laboratorio de RMN, CIQ-UAEM, Av. Universidad 1001. Colonia Chamilpa,

Cuernavaca, Morelos C.P. 62210, México

The need to fabricate nanostructured materials has led us to seek ecological methods that

allow us to care for our environment and reduce costs. In recent years, the green synthesis

show good results in the obtaining of metal nanoparticles as a quick, efficient, cheap and

ecofriendly process. The use of plant extracts gained importance because of the simplicity

by eliminating the elaborate process of maintaining cell cultures and eco-friendliness used in

bacteria and fungi have also been utilized in the synthesis of nanoparticles. We has been

observed that various metabolites in plant extracts have the ability to reduce silver and gold

ions acting as chelating and stabilizers agents of nanoparticles, increasing the

biocompatibility. In this study uses the aquoethanolic extract of Bacopa procumbes as

reducing and stabilizer agent for obtaining gold and silver nanoparticles. The formation of

nanoparticles was by UV-vis spectroscopy and the functional groups on the surface of the

nanoparticles was analyzing by FTIR. The size and morphology was observed by

transmission electron microscopy (TEM).




252

[ NSN-437 ] Study of low temperature photoluminescence

in ZnS:Mn2+ nanoclusters

María del Pilar Gutiérrez Amador ([email protected]) 2 , Arturo

Hernández Hernández 2 , Betsabée Marel Monroy Peláez 3 , Jaime Santoyo

Salazar 1

1 Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, 07000, México D.F.,

México. 2 Escuela Superior de Apan, UAEH, Carretera Apan- Calpulalpan km 8, Apan, Hgo. 43920

México. 3 Instituto de Investigaciones en Materiales-UNAM, Apdo. Postal 70-360, México D.F.,

Coyoacán 04510, México.

Undoped and Mn-doped ZnS nanoclusters have been synthesized by a soft chemistry method

[Zn(1-x)MnxS (0.010≤x≤0.20)]. The average size of nanoclusters is in the range of 3 to 5 nm

in cubic blenda structure. The band gap value decreased from 3.58 eV (for x=0) to 3.24 eV

as a function of mangenese content. The samples with manganese content between 0.05 and

0.15 showed the photoluminescence effect. For higher manganese concentrations this

phenomenon disappears. The PL spectra of Mn-doped ZnS nanoclusters at room temperature

exhibit two emission bands, the 495 nm blue emission host defect-related and the orange 588

nm emission associated with the 4T1-6A1 transition of Mn2+. The blue emission is dominant

at low temperatures (from 10K to 200K) ; while the orange emission is dominant in the range

of 200 K to room temperature. An energy levels scheme is proposed in order to explain the

photoluminescence behavior of the Mn-doped ZnS nanoclusters.




253

[ NSN-440 ] Thermodynamic approach in formation of

Ge nanocrystals on silicon oxide through crystallization

and agglomeration from amorphous thin films.

Arturo Hernández-Hernandez ([email protected]) 3 , Luis Alberto

Hernández-Hernández 4 , Francisco De Moure-Flores 5 , José Guadalupe

Quiñones-Galván 1 , Miguel Meléndez-Lira 2

1 Departamento de Física, CUCEI, Universidad de Guadalajara, Blvd. M. García

Barragán 1421, Guadalajara, 44430, Jal, México C.P. 44430 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, A.P. 14740, C.P. 07300, México, Distrito Federal, México. 3 Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo, Calle Ejido de

Chimalpa Tlalayote s/n Colonia Chimalpa, Apan Hidalgo, México. 4 Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, Edificio 9

U.P. Adolfo López Mateos, Col. San Pedro Zacatenco, C.P. 07730 México DF, México. 5 Facultad de Química Materiales, Universidad Autónoma de Querétaro, Querétaro,

76010, México.

The crystallization process was examined for thin films of germanium on silicon oxide thin

films (SiO2) grown by RF sputtering. Three-dimensional crystalline islands were formed

through crystallization and agglomeration. The mechanism of germanium nanocrystals (Ge-

NCs) formation was discussed on the basis of thermodynamics. In studying the

crystallization of the germanium nanocrystals, the influence of the film-substrate interfacial

energy and surfaces defects should be taken into consideration. It was found that the thickness

of the as deposited amorphous films is an essential factor in determining the crystallization

behavior and in controlling crystal size.




254

[ NSN-442 ] Enhanced Photoresponse of a Metal-Oxide-

Semiconductor Photodetector with Germanium

Nanocrystals Embedded in the Silicon Oxide Layer

Arturo Hernández-Hernández ([email protected]) 3 , Luis Alberto

Hernández-Hernández 4 , Francisco De Moure-Flores 5 , José Guadalupe

Quiñones-Galván 1 , Betsabee Marel Monroy 6 , Guillermo Santana-

Rodríguez 6 , Miguel Meléndez-Lira 2

1 Departamento de Física, CUCEI, Universidad de Guadalajara, Blvd. M. García

Barragán 1421, Guadalajara, 44430, Jal, México C.P. 44430 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto



U.P. Adolfo López Mateos, Col. San Pedro Zacatenco, C.P. 07730 México DF, México. 5 Facultad de Química Materiales, Universidad Autónoma de Querétaro, Querétaro,

76010, México. 6 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, A.

P. 70-360, C.P.04510, Coyoacán, México DF, México.

In this work we report a two-terminal metal-oxide-semiconductor photodetector for which

light is absorbed in a capping layer of germanium nanocrystals embedded in a silicon oxide

matrix grown on p -type silicon substrates. Operated at direct and reverse bias photoresponse

from 900 to 1300 nm was observed. Also, we report on the effect of nanocrystal size on the

photocurrent. The highest optoelectronic conversion efficiency was observed in samples with

smaller germanium nanocrystals. This effect were explained by a transistorlike mechanism,

in which the inversion layer acts as the emitter and trapped positive charges in the dielectric

layer assist carrier injection from the inversion layer to the contact, such that the primary

photocurrent could be amplified.




255

[ NSN-445 ] Optical Properties And Morphology of InAs

Quantum Dots and Quantum Dashes Grown by MBE.

Eric Eugenio López ([email protected]) 1 , Satoshi Shimomura

2 , Víctor Hugo Méndez García ([email protected]) 1

1 Center for the Innovation and Application of Science and Technology (CIACyT), Universidad

Autónoma de San Luis Potosí, Av. Sierra Leona #550, Lomas 2a Sección, SLP 78210, México. 2 Graduate School of Science and Engineering, Ehime University, Bunkyo-cho 3, Matsuyama,

Ehime 790-8577, Japan.

The study of semiconductor quantum dot structures (QDs) is based on improving the control of the

nucleation and to propitiate the self-ordering. This offers the possibility for developing new

generation optical and electronic devices of high performance, taking advantage of their unique atom-

like properties. Nevertheless, despite of their importance, there is still some lack of information in the

self-ordering or nucleation on anisotropic high index substrates (AHIS). In this work, we studied the

morphological and optical properties of self-organized QDs of InAs/GaAs grown by molecular beam

epitaxy (MBE) on GaAs (411)B, (221)B and (100) substrates under different As pressures (PAs=3.1,

4.5 and 6.0x10-6 mbar). Elongated structures, frequently termed as quantum dashes (QDHs) were

observed by atomic force microscopy (AFM) for the samples grown on GaAs (221)B. The QDHs are

oriented along [110]. It is thought that prior to the arrival of the In atoms, the GaAs(221)B surface

was composed by facets naturally self-assembled along that direction [1]. The QDHs length increases

with PAs, however at high PAs surface pits with a density of ~2x109 pits/cm2 appeared. For the samples

grown on the (411)B and (100) surfaces bimodal size distribution of the QDs were observed. Clearly

the density of the QDs varies as a function of PAs: for the large QDs on (411)B, slightly increases 2.2

to 3.2x1010 dots/cm2 while the small islands decreases from 3.4 to 1.1x1011 dots/cm2 when increasing

PAs. For (100) samples the density of the small islands, behaves similarly, decreasing from 4 to

0.3x1011 dots/cm2 and the large QDs did not change with PAs (~4x1010 dots/cm2), but their average

diameter did. The uncompensated evaporation of As due to the high growth temperature of the BL

may have propitiated Ga droplets that acted as nucleation centers and therefore the high density of

QDs. The PAs increment reduces the adatoms diffusion length [2] indicating the formation of large

width InAs islands, as corroborated by AFM. The QDs emission on the (411)B samples as measured

by photoluminescence spectroscopy blueshifted, which was related to alloying effects during the

capping procedure.

[1] F. Grosse, Phys. Rev. Letts., 89, 116102 (2002).

[2] K. Stiles, J. Vac. Sci. & Tech. B, 3, 1089 (1985).

The author acknowledges the financial support of CONACYT, CeMIE-SOL 22, FRCUASLP, INFR-

2015-01: 255489 and PNCPN2014-01: 248071.




256

[ NSN-493 ] Effect of the Energy Fluence on the Optical

and Structural Properties of ZnO Nanoparticles

Synthesized by Laser Ablation of Solids in Liquids

Yryx Yanet Luna Palacios ([email protected]) 3 , Marco Antonio

Camacho López 3 , Miguel Ángel Camacho López 2 , Guillermo Aguilar 1

1 Department of Mechanical Engineering, University of California Riverside, 900

University Ave., Bourns Hall A-341, Riverside, CA, USA. 92521. 2 Laboratorio de Fotomedicina, Biofotónica y Espectroscopia Láser de Pulsos Ultracortos,

Facultad de Medicina, Universidad Autónoma del Estado de México, Jesús Carranza y

Paseo Tollocan s/n. Toluca, México, C.P. 50120 3 Laboratorio de Investigación y Desarrollo de Materiales Avanzados, Facultad de

Química Universidad Autónoma del Estado de México, Campus Rosedal, Km 14.5

Carretera Toluca-Atlacomulco, San Cayetano de Morelos, C.P. 50925

In recent years, Zinc Oxide Nanoparticles (ZnO NPs) have been very important due to their

many applications, for example: solar cells, sunscreens, biosensors due to their optical

properties, and even in biomedicine for cancer cell destruction. The optical and structural

properties of ZnO NPs depend on the synthesis conditions. Mostly these ZnO NPs are

synthesized by chemical methods, however this method provides contaminated ZnO NPs.

On the other hand a physical method such as the Laser Ablation of Solids in Liquids (LASL)

allows to have ZnO NPs free of contaminants and easy modification in the synthesis

parameters, producing ZnO NPs with different optical and structural characteristics. In this

work, we prepared ZnO NPs by LASL at different energy laser fluences. For the synthesis,

we used a pulsed nanosecond Nd-YAG laser with a wavelength of 532 nm, a repetition rate

frequency of 15 Hz and a per pulse energy of 25 mJ, three different energy laser fluences and

acetone like the liquid medium. Samples were characterized by UV-Vis, fluorescence,

Raman spectroscopy and TEM. Results show that using different energy laser fluences during

the ZnO NPs synthesis, their fluorescence emission is not spectrally affected since all the

emission spectra are identical. However the emission intensity increases as the energy laser

fluence is increased, indicating that only the concentration of ZnO NPs in the solution is

affected, but not their size.




257

[ NSN-499 ] Crystalline CdO nanoparticles in an

amorphous matrix of Cd2V2O7 with Er3+ ions

Erika Cervantes Juárez ([email protected]) 5 , José G. Quiñones

Galván 4 , Yadira A. González Rivera 5 , Rosendo L. Lozada Morales 5 ,

Enrique Campos Conzález 1 , Orlando Zelaya Angel 1 , Sergio Jimenez

Sandoval 2 , Efrain Rubio Rosas 3

1 CINVESTAV 2 CINVESTAV, Unidad Querétaro

3 CUVyTT 4 Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías,

Universidad de Guadalajara 5 FCFM-BUAP

Er3+ ions have been introduced into a matrix of Cd2V2O7 using a conventional melt-

quenching method. X-ray diffraction results indicate the presence of approximately 40 nm

sized CdO nanocrystals embedded within the amorphous Cd2V2O7 matrix. The presence of

such nanocrystals was confirmed by transmission electron microscopy. Raman spectroscopy

measurements confirm that the amorphous matrix is composed by Cd2V2O7. The band gap

obtained by optical absorption is 2.84 eV. From the photoluminescence spectrum the

electronic transitions observed are the 2H11/2, 4S3/2,

4F9/2, 4I9/2

→ 4I15/2 and 4S3/2 → 4I13/2 corresponding to Er3+. Thermally activated transport was observed

by dark conductivity measurements taken room temperature to 450 K. The morphology and

chemical composition of the sample were determined by scanning electron microscopy and

energy dispersive spectroscopy respectively.




258

[ NSN-507 ] Green synthesis of stable magnetite Fe3O4

nanoparticles in aqueous extract of hydroponic crops

Araceli Aldana Vázquez ([email protected]) 2 , Jaime Santoyo Salazar


1 2Departamento de Física, Centro de Investigación y Estudios Avanzados del Instituto

Politécnico Nacional, CINVESTAV-IPN, Zacatenco, 07360 México, D.F. 2 Posgrado de Nanociencias y Nanotecnología, Centro de Investigación y Estudios

Avanzados del Instituto Politécnico Nacional, CINVESTAV-IPN, Zacatenco, 07360

México, D.F.

In this work, we report two biosynthesis of Magnetite (Fe3O4) nanoparticles (~10nm)

obtained from dried biomass in aqueous solutions. The green precursors used were extracts

of (1) greenhouse hydroponic lettuce (Lactuca sativa: a plant that generates lots of root and

Biomass) and (2) Sumac leaves (Rhus typhina). The advantages of these routes are green

technology of low cost and reproducible processing. The extracts from these plants have ion

precursor high tannin biomolecule, which is the main organic chain to produce the chemical

reaction between water and metal ions. The control of particle size of Magnetite (Fe3O4)

during the reactions depends from pH and molar concentration in air. Nanoparticles were

analysed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy

(SEM), X-Ray Electron Diffraction Scattering (EDS) and X-Ray Diffraction (XRD). These

results are contribution to consider this synthesis method for future extend of large scale

production.

Keywords: Bioreduction, Tannin, biomass, nanoparticles.

Acknowledgments:

Conacyt Ph.D. and CINVESTAV-IPN Fellowships.

Conacyt Project (Sa/ZAC/FI/2013/000765), Lotto BioNano Laboratories and CINVESTAV-

IPN.




259

[ NSN-512 ] Study of ablation and thermal damage

induced by laser irradiation in nanostructured materials

Lis Tamayo-Rivera ([email protected]) 1 , Emma Vianey García-

Ramírez 2 , Ariadna Sánchez-Castillo 1 , José Alfredo Pescador-Rojas 1 ,

Jorge Alejandro Reyes-Esqueda 2

1 Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo,

Apan, Hgo, CP.43920, México 2 Instituto de Física, Universidad Nacional Autónoma de México, Ciudad

de México. CP.04510, México

Metal nanoparticles embedded in a dielectric matrix have become one of the most interesting

systems, due to the presence of so-called Surface Plasmon Resonance. Those materials and

its nonlinear optical interactions have been widely studied; however, the origin of the

nonlinear response and its dependence with the Surface Plasmon Resonance has not been

clearly understood yet. It is well known that, resonant nonlinear response is bigger than non-

resonant nonlinear response; however, linear absorption in resonant regime can also be

injurious because a large amount of the incident energy is absorbed by the sample to be

released thermally by a non-radiative process. The electromagnetic energy absorbed causes

an increase in local temperature, and with it, a structural change in the irradiated area. To be

able to explain the mechanisms behind the nonlinear response it is necessary to separate the

desired phenomena in the nonlinear regime from the possible permanent changes induced in

the material.

In this paper we show the presence of optical ablation and thermal damage induced by laser

irradiation in nanostructured materials. The work aims to identify the observed damage in

the sample: deformation, aggregation and ablation of nanostructures; as a function of the

local temperature reached, i.e, as a function of the optical energy absorbed by the sample.




260

[ NSN-518 ] Thermal Analysis in Air and Nitrogen

Atmospheres of Single Wall Carbon Nanotubes by

Raman Spectroscopy.

Leticia Ithsmel Espinosa Vega ([email protected]) 1 ,

Ricardo Guirado López 2 , Ángel Gabriel Rodríguez Vázquez 1

1 Coordinación para la Innovación y la Aplicación de la Ciencia y la Tecnología

(CIACYT), Universidad Autónoma de San Luis Potosí, Universidad Autónoma de San Luis

Potosí, Álvaro Obregón 64, San Luis Potosí, S.L.P., 78000, México 2 Instituto de Física, “Manuel Sandoval Vallarta”, Universidad Autónoma de San Luis

Potosí, Álvaro Obregón 64, San Luis Potosí, S.L.P., 78000, México

Given the widespread applications of carbon nanotubes it is very important to know their

behavior under extreme physical conditions one of them it is the sensitivity of carbon

nanotubes, used as NO2 sensors, is found to be largely influenced by oxidative treatment so

it is necessary a complete analysis about the comportment that this kind of materials have in

different atmospheres to heated.

The temperature dependence of the Radial Breathing Mode Raman spectra of Single Wall

Carbon Nanotubes (SWCNT) is irreversible under the presence of oxygen, but it is reversible

up to 1000 K in nitrogen ambient. We present a combined experimental and theoretical study

using Density Functional Theory (DFT) calculations and molecular dynamics simulations, in

order to analyze the structural properties and chemical reactivity in the SWCNT. Our results

shows that the irreversibility is due to degradation of the SWCNT produced by a dissociative

chemical adsorption of oxygen by intrinsic defects on the nanotube surface. Oxygen opens

the nanotubes forming semitubes that lead to the different diameter distribution observed by

Raman scattering. In the absence of oxygen, the associative chemical adsorption of nitrogen

by the intrinsic defects avoids the opening of the nanotubes up to 1000K. Additionally,

Raman spectroscopy in back-scattering geometry has been used for the characterization in a

complete process were the carbon nanotubes are heating in nitrogen ambient at 1000 K and

then in oxygen ambient until the same temperature. We observe than the annealing in

nitrogen avoids the damage in the sample heating in oxygen and the Raman spectra remains

stable.




261

[ NSN-531 ] Low temperature magnetic behavior of

CoFe2O4 nanofibers obtained by electrospinning

Diana María Carrillo Flores ([email protected]) 2 , José Trinidad

Elizalde Galindo 2 , Carlos Ornelas Gutiérrez 1 , José Rurik Farias Mancilla

2

1 Centro de Investigación en Materiales Avanzados, Miguel de Cervantes 120, 31109,

Chihuahua, Mexico 2 Department of Physics and Mathematics, Instituto de Ingeniería y Tecnología,

Universidad Autónoma de Ciudad Juárez, Av. Del Charro 450 norte, 32310, Ciudad

Juárez, Mexico.

The synthesis of the CoFe2O4/Fe2O3 nanofibers was carried out by the electro-spinning in

order to study the effect of grain size distribution achieved on the magnetic properties when

measured at low temperatures. In this work, the precursor solution was compose of 8%Wt

of PVP, with molecular weight Mw 1, 300 K, and 7.65 g of Co(NO3)26H2O and

Fe(NO3)26H2O in water. The solution was heated at 60 °C with vigorous stirring for 3 h and

then delivered into a metallic needle at a constant flow rate of 0.3 ml/h. After collecting the

fibers, these were annealed at 750°C by 1 h. The characterization was carried out by X-ray

diffraction (DRX), Transmission Electron Microscopy (TEM) and Vibrating Sample

Magnetometry (VSM). XRD patterns exposed a CoFe2O4 as the main phase present in the

nanofibers with a cell parameter a = 8.3381 Å. Characterization of morphology carried out

with TEM revealed a wide distribution of grain sizes, ranging from 40 to 240 nm. Finally,

magnetic properties of calcined samples characterized by VSM, shown a strong temperature

dependence of hysteresis loops shape, going from single-phase loops for room temperature

to wasp-waisted shaped loops for low temperatures. It show up a change in the magnetic

interactions as temperature goes down because the grain size distribution of nanoparticles

composing the nanofibers and the different magnetic anisotropy of CoFe2O4 and Fe2O3

phases, being these the underlying responsibles of the hysteresis loops shape.




262

[ NSN-532 ] Nanostructure and magnetic properties of

electropun MnFe2O4 nanofibers

Lizeth Vázquez Zubiate 2 , Diana María Carrillo Flores 2 , Pierre Giovanni

Mani González 2 , Carlos Ornelas Gutiérrez 1 , José Trinidad Elizalde

Galindo ([email protected]) 2

1 Centro de Investigación en Materiales Avanzados, Chihuahua, Mexico. 2 Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, Universidad

Autónoma de Ciudad Juárez, Chihuahua, Mexico

The synthesis of the MnFe2O4 nanofibers was carried out by the electro-spinning in order to

study the effect of grain size distribution achieved on the magnetic properties when measured

at low temperatures. In this work, the precursor solution was compose of 10%Wt of PVP,

with molecular weight Mw 1, 300 K, and 8.7 g of Mn(NO3)26H2O and Fe(NO3)26H2O in

water. The solution was vigorously stirred for 2 h and then delivered into a metallic needle

at a constant flow rate of 0.5 ml/h. After collecting the fibers, these were calcined at 800°C

by 4 h in air atmosphere. The characterization was carried out by X-ray diffraction (DRX),

Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometry (VSM).

MnFe2O4 pure phase was found in the nanofibers from XRD patterns. TEM micrographs

revealed a fibers diameter around 600 nm and a wide distribution of grain sizes, ranging from

20 to 100 nm. Magnetic properties of calcined samples characterized by VSM were measured

at low temperature to determine the magnetic interactions behavior of the fibers. It was found

a change in the magnetic interactions as temperature goes down because the

magnetocrystalline anisotropy dependence on it by means of delta M curves.




263

[ NSN-541 ] Novel solution process for synthesis of

CZTS nanoparticles using oleylamine as solvent

Arturo Méndez-López ([email protected]) 2 , Arturo Morales-Acevedo

1 , Yuliana de Jesús Acosta-Silva 2 , Mauricio Ortega-López 2

1 Depto. de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, Avenue IPN No. 2508, 07360 Mexico City, DF, Mexico 2 Sección de Electrónica del Estado Solido (SEES), Depto. de Ingeniería Eléctrica, Centro

de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Avenue IPN

No. 2508, 07360 Mexico City, DF, Mexico

Chalcopyrite, Cu2ZnSnS4 (CZTS), is widely applied in the fabrication of thin-film solar

cells, due to its high efficiency and stability. The high costs and complexity of vacuum

processes have driven the development of non-vacuum methods, such as solvothermal

approaches using organic solvents and metal salts. To overcome the problems of energy

waste and carbon residue, this study synthesized ink of CZTS nanoparticles using the hot-

injection method at 230 °C . The resulting CZTS particles were characterized by XRD,

Raman, SEM, TEM and UV–vis to investigate the crystal structure, composition,

morphology, and band gap. This paper demonstrates the considerable potential for the

synthesis of nanoscale CZTS particle ink using a low-cost, simple process, applicable for

mass production.




264

[ NSN-545 ] Study of the formation of 2DEG in

AlGaAs/GaAs n-doped interface

J. Antonio Rojas Rosales ([email protected]) 1 , Gelacio Atondo

Rubio 1 , Oscar J. Velarde Escobar 1 , Francisco Ramos Brito 1 , Cristo M.

Yee Rendón 1

1 Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Sinaloa

We study the formation of 2DEG in n-AlGaAs/AlGaAs/GaAs structure, as function of the

doping and the space layer between the n-doped AlGaAs and the GaAs layer. We realized

self-consistent calculations of quantum bound states of the 2DEG. The problem is solved by

discretization of the structure and converting the Schrödinger equation into a central

difference and the solving the system by using a shooting method. For solving the Poisson

equation we used the same discretization than before and solve for a central difference

equation and then enforcing the self-consistent scheme to compute the energy for the 2DEG.

We compare our results with the modified Fang-Howard approximation.




265

[NSN-574] TiO2 inverse opals with palladium

nanoparticles inclusions as active film in chemical

sensors

M. P. Sampedro ([email protected])1, B. Zenteno-Mateo2, M.

López Fuentes1, Morales Sánchez M. A1, Hernández Santiago A. A.3, Rojas

Rodríguez J. F4.

1Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla. C.P.

72570, Puebla, México. 2 Facultad de Ingeniería BUAP, Bulevar Valsequillo y Circuito CU, Ciudad Universitaria

Puebla, Pue. México. 3Facultad de Ciencias Químicas, Laboratorio de Química Biofísica, Benemérita

Universidad Autónoma de Puebla. C.P. 72570, Puebla, México 4Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla.

C.P.72570, Puebla, México.

The TiO2 opals were functionalized with palladium nanoparticles and were used in the

fabrication of chemical sensors for the detection of hydrogen (H2) and ammonia (NH3) using

hydrogen concentrations in the order of parts per million (ppm) at moderate temperatures

(200-500°C). The results showed that the inclusion of palladium nanoparticles on the surface

of TiO2 opals improves the sensing performance. Particularly the sensor response increased

two-fold and the time constants were reduced to seconds, in comparison with the sensor

without palladium nanoparticles at the optimal sensor operating temperature. These results

show that the TiO2 inverse opals are an excellent option in the development of third-

generation gas sensors.





266

PHOTOTHERMAL PHENOMENA,

PLASMA AND VACUUM (PPPV) Chairman: Citlali Sánchez Aké (CCADET-UNAM)

Oral Session

INVITED TALK [ PPP-87 ] Photoacoustic Characterization of Green, Red and

Dehydrated Capsicum annuum L. variety Pasilla

Francisco Hernández-Rosas 1 , Víctor Rodrigo Barrientos-Sotelo 3 , Rogelio

Cano-Casas 3 , Alejandro Benitez 3 , Alfredo Cruz-Orea 2 , Juan Hernández-

Rosas 3

1 Colegio de Postgraduados, Campus Córdoba, Km.348 Carretera Federal Córdoba-

Veracruz, Congregación Manuel León, Amatlán de los Reyes, Ver., 94946, México 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN,

Apartado Postal 14-740, México D.F. 07360, México 3 Instituto Politécnico Nacional UPIITA, Av. IPN, No. 2580, Col. La Laguna Ticomán, Del.

Gustavo A. Madero, México D.F., 07340, México

Chili peppers are an important part of the Mexican diet, such that today they are integrated

in the cultural traditions inherited from pre-Columbian ancestors. Nevertheless, research on

the chili pepper is still needed. In this work, we used photoacoustic spectroscopy (PAS) to

specifically characterize Capsicum annuum L. variety pasilla in three different stages: green,

red and dried. Measuring their optical properties using the photoacoustic technique we

monitored physiological and biochemical changes occurring in the samples during ripening

and drying. Several processes, such as water stress, occur during ripening and dehydration to

promote the biosynthesis of new compounds, such as various carotenoids, that are clearly

visible in the absorption spectra. In order to obtain information about another physical

parameters, we have also measured the moisture content of these peppers and the

permeability of their cuticles beginning from the unripe stage until ripening and dehydration

of the pasilla peppers.

Keywords: photoacoustic spectroscopy; water vapor, diffusion coefficient; water stress.

*[email protected]

mailto:*[email protected]




267

[ PPP-107 ] Polycaprolactone thin films synthesized by low

pressure plasma polymerization.

J. Antonio Lopez Barrera ([email protected]) 1 , Roberto Olayo

Valles ([email protected]) 2 , Juan Morales Corona 2

1 Academia de Física, Universidad Autónoma de la Ciudad de México Plantel Cuautepec,

Av la Corona # 320, col Loma la Palma 2 Departamento de Física, Universidad Autónoma Metropolitana Unidad Iztapalapa, Av

San Rafael Atlixco 186, col Vicentina

We demonstrate the plasma polymerization of e-caprolactone (e-CL) at low pressure. Thin

films of plasma-polymerized e-CL were deposited on glass slides and KBr pellets in a tubular

plasma reactor at 0.6 mbar. All polymerizations were performed for 120 min with a radio

frequency of 13.5 MHz and power was varied between 50 and 120 W. The films were

characterized by XRD, TGA, DSC, SEM, and Raman and infrared spectroscopy.

Additionally, the water contact angle with the film surface was measured. The results show

that the plasma-polymerized e-CL films are significantly different chemically and

topologically from poly(e-caprolactone) films. The films prepared by plasma polymerization

were used as cell culture surfaces for smooth muscle cells.




268

[ PPP-188 ] Pulsed photoacoustic study of Ag and Au

nanoparticles obtained by laser ablation in ethanol

Enrique Esparza Alegría ([email protected]) 2 , Miguel Angel

Valverde Alva 5 , Tupak García Fernández 6 , Citlali Sánchez Aké 1 , Rosalba

Castañeda Guzmán 1 , Mayo Villagrán Muniz 1 , José Luis Sánchez

Llamazares 4 , Cesar F. Sánchez-Valdés 4 , M.B. De la Mora 1 , Jean Yves

Tovar Sánchez 2 , Ciro Eliseo Márquez Herrera 3

1 CCADET, Universidad Nacional Autónoma de México (UNAM), México D.F., C.P.

04510, México. 2 Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), México D.F.,

C.P. 04510, México. 3 Facultad de Química, Universidad Autónoma de México (UNAM), México D.F., C.P.

04510, México. 4 Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San

José 2055, Col. Lomas 4ª sección, San Luis Potosí, S.L.P., C.P. 78216, México 5 Posgrado en Ciencia e Ingeniería de Materiales, Universidad Nacional Autónoma de

México (UNAM), México D.F., C.P. 04510, México. 6 Universidad Autónoma de la Ciudad de México (UACM), Prolongación San Isidro 151,

Col. San Lorenzo Tezonco, México D.F., C.P. 09790, México.

Colloidal silver and gold nanoparticles were obtained through laser ablation in ethanol by

using a pulsed Nd:YAG laser with 1064 nm of wavelength and nanosecond pulse duration.

Different parameters as energy, spot area, number and repetition rate of the laser pulses were

varied during the experiments. The size distribution and shape of the nanoparticles were

obtained by transmission electron microscopy. The absorption spectra of the colloids showed

the respective plasmon absorption peaks. The pulsed photoacoustic (PA) technique was used

to study the ablation process and its influence in the synthesized colloids. This technique

allowed to determine both the production rate per laser pulse and concentration of the

synthesized NPs. The PA analyses showed a significant reduction of the production rate of

the NPs during the first hundreds of the laser pulses. The colloids were also analyzed by

atomic absorption spectroscopy that allowed to calibrate the results obtained by pulsed PA

technique.

Keywords: pulsed photoacousticanalysis; laser ablation in liquid; synthesis of silver

nanoparticles




269

[ PPP-201 ] Optoacoustic approach for the characterization of

ultrasound and optoacoustic phantoms

Bartolome Reyes-Ramírez ([email protected]) 1 , Gerardo

Gutiérrez-Juárez 1 , Luis Polo-Parada 2 , Crescencio García-Segundo 3

1 Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Universidad de

Guanajuato 2 Department of Medical Pharmacology and Physiology, Dalton Cardiovascular Research

Center, University of Missouri-Columbia 3 Imagenología Biomédica: Física y Computacional, Centro de Ciencias Aplicada y

Desarrollo Tecnológico, Universidad Nacional Autónoma de México

In the last decade development of medical ultrasound devices with frequencies higher to 20

MHz propose new challenges. Some of this is the characterization of test phantoms

manufactured from tissue-mimicking-material, which are used to calibrate, assess and

quantify the performance of ultrasound scanners. To do this characterization, some physical

properties have to be measure; among them are sound speed, impedance, absorption and

attenuation of the beam through the tissue. In this study, the thermoelastic model of the

optoacoustic effect with one degree of freedom in the spatial coordinates for a plane sample

was studied in order to assess the ultrasound speed of solid and semisolid samples as potential

phantoms. The model proposed considers a sample with thickness , Beer’s law absorption

immersed in a no absorbent fluid with different acoustical impedance. It was show that the

optoacoustic signal, in the transmission mode of detection, is composed mainly by a pairs of

pulses, with time interval between both pulses equal to , here is the sound

speed of the sample [1]. In order to use this result as a method to measure the phantom sound

speed, we realize a series of experiments with liquids solutions of cupper nitrate. The

optoacoustic pressure was generated by nanosecond laser pulses and registered by homemade

capacitive sensors with 28 μm thick Polyvinylidene Fluoride films operating in the

piezoelectric mode. The thickness of the sample was 12 mm. The sample sound speed was

measured with the approach proposed and using another optoacoustic configuration that is

independent of model. The values obtained were 1563 m/s and 1560 m/s, respectively.

[1] Solution for the photoacoustic wave equation with a single spatial degree of freedom,

Beer's law absorption of radiation and mechanical barriers. F. Herrerías-Ascué, A. González-

Vega, J. Torres-Arenas, and G. Gutiérrez-Juárez. Modern Physics Letters B, 27(18), article

number: 1350135 (20 July, 2013).




270

[ PPP-255 ] Influence of film thickness, fluence and number of

pulses on the synthesis of Au nanostructures by laser

annealing

Jimena Martínez de León Mármol ([email protected]) 1 , Citlali

Sánchez Aké 1 , Tupak Ernesto García Fernández 2

1 Laboratorio de Fotofísica, Centro de Ciencias Aplicadas y Desarrollo Tecnológico,

Universidad Nacional Autónoma de México, Apartado Postal 70-186, México D.F., C.P.

04510, México 2 Universidad Autónoma de la Ciudad de México (UACM), Prolongación San Isidro 151,

San Lorenzo Tezonco, México D.F., C.P. 09790, México

In the last few years metallic nanoparticles and nanostructures have attracted significant

interest due their multiple applications of their plasmonic properties. Nowadays there are

several techniques to fabricate them, although not all of them are easy, unexpensive or

sustainable. Laser annealing is a relatively new technique which has the advantages of being

accessible, environment friendly, can be used on multiple materials and substrates, and can

also be set to obtain patterns or other structures. However, it is still used mostly empirically

and the exact phenomenon is still being studied.

Many parameters interfere during the physical processes in this technique such as the material

to be treated, the substrate, surrounding atmosphere, applied energy, pulse duration, among

others. This work exhibits qualitatively the influence of three chosen variables: energy

density (fluence) of the irradiating beam, thickness of the original deposited film and number

of pulses received during the treatment. Au films of different initial thicknesses have been

deposited previously over glass substrates to be laser annealed using a Nd:YAG laser (355nm

operated with a repetition rate of 10Hz and 8ns of pulse lenght). Different values of

laser fluence have been used. Finally, the treatment under such conditions has been repeated

for different number of pulses. The resulting nanostructures have been characterized by SEM

and UV-Vis spectrometry. The tendencies obtained in this study will make the further usage

of this technique more precise and easier to handle.




271

[ PPP-425 ] Design and characterization of a Chromel-Alumel

thermionic converter

José Guillermo Pérez Luna ([email protected]) 1 , Steffanie Jiménez

Flores ([email protected]) 2 , Antonio Esteban Jiménez Gonzalez 3 ,

Salvador Alcántara Iniesta 2

1 Facultad de Ciencias de la Electrónica, Benemérita Universidad Autónoma de Puebla,

Av. 14 sur y Av. Sn Claudio, Ciudad Universitaria, Puebla Pue., México, CP 72560. 2 Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Av. 14 sur y Av. Sn

Claudio, Ciudad Universitaria, Puebla Pue., México, CP 72560. 3 Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Priv.

Xochicalco S/N, Temixco Mor, México, CP 62580

The design and characterization of a thermionic converter (TC) made with electrodes of

chromel and alumel is presented. These electrodes are cylindrical form and are located over

a vertical structure isolated by ceramic elements. A chromel cylinder is used as the anode

while an alumel cylinder is used as the cathode. In the internal cavity of the anode is located

a tungsten filament heater. The TC includes an aluminum base and a glass dome that maintain

vacuum by using an O-ring located between them. A dual valve is connected at the aluminum

base for air extraction and nitrogen introduction. A special curve tracer module was designed

to measure the small current generated by the TC. A parametric study for different

temperatures in the electrodes was made. Parametric curves for vacuum and nitrogen plasma

were obtained for their comparison.




272

[ PPP-500 ] In situ photoacustic characterization for porous

silicion growing: detection principles

Cristian Felipe Ramirez Gutierrez ([email protected]) 1 ,

Anderzon Felipe Palechor Ocampo 1 , Mario Enrique Rodriguez Garcia




The electrical and optical properties of porous silicon (PS) had been widely studied in recent

years, and it is well know that the porous silicon (PS) properties depend on porosity, and

porosity depends on growing parameters choose for the electrochemical process. Usually PS

films are characterized after the electrochemical etch using techniques like scanning electron

microscopy (SEM), in order to obtain surface and cross-section parameters that allows the

determination of thickness and porous size; profilometry had been used to determine

interface roughness; and gravimetry to determine the porosity.These techniques are contact,

destructive, and are not able to give information at the same time that the etching process is

forming of PS.

In this work we develop a photoacoustic cell coupled to electrochemical cell for characterize

the growing of PS. The detection is based on the changes in the reflectance coefficient. The

changes in the reflectance coefficient is a response of the changes in the thickness of PS and

the optical properties of the film.

It shows the dependence of photoacoustic signal of the wavelength of the laser and current

density of the electrochemical etch, and the same time we have been doing a simple

description of the differential equation of the heat diffusion with the reflectance corrections

to reproduce the photoacoustic signal obtained.




273

Sesión Poster

[ PPP-30 ] Photoacoustic technique in the study of

photosynthesis aquatic lirium (eichhornia crassipes) exposed

to ultrasound

Jeniffer Calderón ([email protected]) 1 , Alejandro Rojas 2 , Leslie

Salazar 2 , Maira Jiménez 2 , Antonio Calderón 1 , Gabriel Peña 3

1 Instituto Politécnico Nacional, Unidad CICATA Legaria. 2 Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología.

3 Universidad Francisco de Paula Santander, UFPS, Colombia.

Eichhornia Crassipes, water hyacinth, is a free float plant native of the Amazon, Brazil, which

by the beauty of its flowers has been propagated to almost all the tropical and sub-tropical

regions of the world. This plant is a weed, which causes consequences extremely unfavorable

for the environment and for the diverse human activities that are developed in the bodies of

water. We report the effect of the intensity of ultrasound (US) in the photosynthetic activity

of Aquatic Lirium (Eichhornia Crassipes), specifically the absorption spectrum of the

photosynthetic pigments using the photoacoustic technique. For this, we use power densities

values of US irradiation of 1 mW/cm2, 8 mW/cm2 and 16 mW/cm2, with a frequency of

17Khz and five hours of exposure time, in all cases.

We show the effect of US irradiations to generate cavitation in the watery parts of the Aquatic

Lirium or water hyacinth, in order to obtain inhibition of its photosynthetic activity. These

results show the utility of the ultrasound irradiation, as well as, the importance the

photoacoustic technique in the photosynthesis monitoring in Aquatic Lirium.




274

[ PPP-120 ] Diagnostics of the combination of silicon and

bismuth plasmas in a nitrogen atmosphere

Enrique Camps ([email protected]) 1 , Johans Restrepo 1 , Johans

Restrepo 2 , Stephen Muhl 3

1 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado

Postal 18-1027, México D.F. C.P. 11801, México 2 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,

Apartado Postal 70-360, Coyoacán, México, D.F. 04510, México 3 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,

Apartado Postal 70-360, Coyoacán, México, D.F. 04510, México.

In this work two laser ablation plasmas which expand perpendicularly to each other, in a

nitrogen atmosphere, were studied using optical emission spectroscopy and a planar

Langmuir probe. The plasmas were formed by the ablation of silicon and bismuth targets.

The Langmuir probe was used to measure the mean kinetic ion energy and the plasma

density. The optical emission spectroscopy was used to determine the excited chemical

species present in the plasmas, as well as their temporal behavior. This study was carried out

at pressures between 2 and 40 x 10-3 Torr and laser fluences between 2 and 15 J/cm2. During

the ablation of the silicon target in the nitrogen atmosphere we observed species

corresponding to single and double charged Si ions, excited neutral silicon and singly ionized

molecular nitrogen. For the case of the ablation of the bismuth target the observed species

corresponded to excited neutral bismuth. The main emitting species depended on the working

pressure and the energy of the ablated ions. During the simultaneous ablation of the two

targets, the intensity of the emitting species increased, however the type of species remained

the same. The fluence applied to the bismuth target was chosen so that the bismuth ion

energy was kept constant at around 50 eV with a plasma density of 5.5 x 10 11 cm-3, and for

the case of the silicon target the ion energy was fixed at different levels in order to study the

influence of the energy and plasma density on the type of excited species.




275

[ PPP-169 ] Thermal characterization of Castor oil as additive

in lubricant oil by photothermal techniques

Gemima Lara-Hernández 2 , José de Jesús Agustín Flores-Cuautle

([email protected]) 1 , José de Jesús Agustín Flores-Cuautle 3 ,

Eder Contreras-Gallegos 4 , Alfredo Cruz-Orea 2 , Juan Carlos Benavides-

Parra 2

1 Catedras CONACyT, Consejo Nacional de Ciencia y Tecnologia, Av. Insurgentes Sur

1582, Del. Benito Juarez C.P.: 03940, Mexico. 2 Departamento de Física, CINVESTAV-IPN, Av. IPN No. 2508, Col. San Pedro Zacatenco,

07360 Mexico, DF, Mexico. 3 Maestria en Ingeniera Electronica, Division de Estudios de Posgrado e Investigacion,

Instituto Tecnologico de Orizaba, Orizaba, Ver. Mexico. 4 Sección de Estudios de Posgrado en Investigación-ESIME-IPN, U.P.A.L.M., Col. San

Pedro Zacatenco, 07730 Mexico, DF, Mexico.

Over the last years extensively research has been carried out on full or partial substitution of

supplies resources coming from renewable resources on traditionally non-renewable, in the

case of the automobile sector there are progresses in bio-combustibles (biofuel) [1-3] and

synthetic oils coming from vegetable sources [4, 5].

There are strong efforts to find oil additives which can improve oils features in automobile

industry, by adding vegetables oils to commercial lubricant oils, is expected to improve oil

thermal stability. By using the so-called thermal wave resonator cavity (TWRC) and inverse

photopyroelectric technique, different ratios of castor oil (ricinus comunis)-motor oil blends

were obtained and their thermal properties were characterized.

Several oil-additives concentrations (95%-5%, 90%-10%, 85%-15%, 80%-20%) were

measured and thermal diffusivities and effusivities as well as densities are reported, getting

full thermal characterization for every concentration.

[1] Balafoutis A, Fountas S, Natsis A, Papadakis G. Performance and Emissions of Sunflower,

Rapeseed, and Cottonseed Oils as Fuels in an Agricultural Tractor Engine. ISRN Renewable Energy

2011;2011:12.

[2] Biodisel. 2015.

[3] Vegetable oil as diesel fuel? J Am Oil Chem Soc 1980;57:A805-A19.

[4] Campanella A, Rustoy E, Baldessari A, Baltanás MA. Lubricants from chemically modified

vegetable oils. Bioresource Technology 2010;101:245-54.

[5] Adhvaryu A, Erhan SZ, Perez JM. Tribological studies of thermally and chemically modified

vegetable oils for use as environmentally friendly lubricants. Wear 2004;257:359-67.




276

[ PPP-179 ] Thermal and Optical characterization of

sunscreen creams by using Photothermal Techniques

Elizabeth Díaz Torres ([email protected]) 2 , Margarita Lizeth

Alvarado Noguez ([email protected]) 2 , Alfredo Cruz Orea 1 ,

Feliciano Sanchez Sinencio 1

1 Departamento de Física CINVESTAV-IPN 2 ESFM-IPN

The thermal and optical characterization of sunblock oils and creams is important, among

other reasons, because they protect the human skin against the UV radiation [1]. In the present

study the thermal effusivity and optical absorption spectra of several sunscreen creams were

obtained by using two photothermal techniques. The Inverse Photopyroelectric (IPPE)

configuration [2] and the Photoacoustic spectroscopy (PAS) [3] techniques were used to

obtain the thermal effusivity and optical absorption spectra of the samples respectively.

Sunblock creams with different sun protection factors were studied by obtaining their optical

absorption coefficient as a function of the incident wavelength. Also these samples were

exposed to UV light by several times to monitor their degradation by PAS.

References

[1] Gabriela Badea, Ioana Lăcătuşu, , Nicoleta Badea, Cristina Ott, Aurelia Meghea, Use of

various vegetable oils in designing photoprotective nanostructured formulations for UV

protection and antioxidant activity, Industrial Crops and Products 67: 18–24 (2015).

[2] A. Mandelis and M. M. Zver “Theory of photopyroelectric spectroscopy of solids”

J.Appl. Phys. 57(9) 4421-4430 (1985).

[3] C. Hernandez Aguilar, A. Cruz Orea, R. Ivanov, A. Dominguez, A. Carballo, I. Moreno

and R. Rico, “The optical absorption Coefficient of Maize Seeds Investigated by

Photoacoustic Spectroscopy” Food Biophysics 6:481-486 (2011).




277

[ PPP-233 ] Photoacoustic Characterization of Thin

Semiconductor Films


Rodríguez-Fragoso 2 , Julio Gregorio Mendoza-Álvarez 2 , Gerardo

González de la Cruz 2

1 FCE-BUAP 2 Physics Department-CINVESTAV

Thermal conductivity, thermal diffusivity and thermal interface conductivity of

semiconductor thin film samples on substrate were investigated by means of the

photoacoustic technique. The investigated films were grown by liquid phase epitaxy

technique. The thermal properties of the samples are identified by comparison with an

analytical solution obtained solving the one-dimensional heat conduction across the film and

substrate. In particular, the fitting parameter is normalized to one obtained with a reference

sample to obtain the thermal conductivity. Furthermore, the determination of the interface

thermal conductivity between the film and the substrate gives a qualitative measure of the

disorder at the interface. This latter parameter plays an important role on heat transport in

layered materials. We estimated the thermal diffusivity, thermal conductivity and the

interface thermal conductivity of the ternary InAsSb and quaternary InGaAsSb layers

deposited on GaSb (470 mm in thickness) were measured and found to be 0.274 cm2/s, 0.252

W/cm K and 235W/cm2 k for the ternary film and 0.2187cm2/s, 0.287W/cm K and

73.46W/cm2 K for the InGaAsSb film.




278

[ PPP-260 ] Thermal conductivity measurement in concrete

with spheres of clay and polystyrene by means of the hot disk

technique

Jonathan Félix Guarachi Solano 1 , José Antonio Calderón Arenas 1

1 1Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada Unidad Legaria del

Instituto Politécnico Nacional, Av. Legaria 694 Col. Irrigación, Del. Miguel Hidalgo, C. P.

11500 México D. F., México.

Disc-shaped samples of concrete composite, with diameter of 6.4 cm and thickness of 3.2

mm, were used. Each sample consisted of spheres, of clay and polystyrene, embedded in

concrete. In order to ensure the assumptions of an infinite medium and not completely

penetrating heat flux through the sample in the axial direction, two of these composite disks

were stacked together above the sensor and two more stacked below it, giving us a double

thickness of sample. This stacking of disks allowed the generation of more reproducible

data.

The Hot Disk Thermal Constants Analyzer is an emerging technology that uses the transient

plane source technique to measure the in-plane and through-plane thermal conductivity of an

anisotropic material in the same test. The sensors used in this test method consisted of a

10µm thick nickel foil embedded between two 25.4 µm thick layers of Kapton polyimide

film. The nickel foil was wound in a double spiral pattern and had a radius, R of 6.403

mm. For the more conductive samples the sensor with the larger radius was used. The

thermal conductivities were measured at 23oC. Since the test specimens are anisotropic, this

test method is suitable for this project.

We obtained a reduction of up 50% in the thermal conductivity of the composite samples

comparing with samples only of concrete.

Keywords: Thermal conductivity, thermal diffusivity, concrete.




279

[ PPP-294 ] Thermal characterization of biodiesel including

metallic nanoparticles

Genaro López Gamboa 3 , Genaro López Gamboa 4 , José Luis Jiménez

Pérez 3 , Zormy Nacary Correa Pacheco 2 , José Francisco Sánchez-

Ramírez 1

1 CIBA-Instituto Politécnico Nacional, San Juan Molino Km 1.5 de la Carretera Estatal

Sta. Inés Tecuexcomac-Tepetitla, Tlaxcala, 90700 México 2 Instituto Politécnico Nacional-Centro de Desarrollo de Productos Bióticos. Carretera

Yautepec–Jojutla, km 6.8, San Isidro, Yautepec, Morelos, México CP 62730 3 UPIITA-Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2580. Barrio

Laguna Ticomán, 07340. México D.F. 4 Universidad Politécnica del Valle de Toluca (UPVT) km 5.7 Carretera Almoloya de

Juárez, Santiaguito Tlalcilalcali, C.P. 50904 Edo. México, México

Jatropha biodiesel was prepared using alkaline catalysts. Au nanoparticles with different

concentrations were prepared by redox method. The nanoparticles (size φ = 13 nm) were

mixed with biodiesel obtaining the bionanofluids with different concentrations. Thermal lens

technique was used to characterize the thermal properties of biodiesel containing Au

nanoparticles in order to observe how the presence of nanoparticles influences the

bionanofluids thermal diffusivity. The characteristic time constant of the transient thermal

lens was estimated by fitting the experimental data to the theoretical equations. An increase

in the thermal diffusivity for the Au nanoparticles dispersed in biodiesel was observed as

concentration of nanoparticles was increased. UV-Vis spectroscopy and TEM were used in

order to characterize the bionanofluids.




280

[ PPP-295 ] Photothermal techniques applied for

characterization of soybean nanobiodiesel

José Luis Jiménez Pérez ([email protected]) 3 , Genaro López

Gamboa 3 , Genaro López Gamboa 4 , Zormy Nacary Correa Pacheco 2 ,

José Francisco Sánchez-Ramírez 1 , Juan Ignacio Escorza Chávez 3

1 CIBA-Instituto Politécnico Nacional, San Juan Molino Km 1.5 de la Carretera Estatal

Sta. Inés Tecuexcomac-Tepetitla, Tlaxcala, 90700 México 2 Instituto Politécnico Nacional-Centro de Desarrollo de Productos Bióticos. Carretera


Laguna Ticomán, 07340. México D.F. 4 Universidad Politécnica del Valle de Toluca (UPVT) km 5.7 Carretera Almoloya de

Juárez, Santiaguito Tlalcilalcali, C.P. 50904 Edo. México, México

Thermal properties of diesel added with nanoparticles could be increased comparing to

conventional diesel. This work deals with the enhancement of thermal conductivity of

nanofluids from soybean biodiesel added with spherical Ag nanoparticles. Thermal lens

spectrometry in the mismatched dual-beam mode was used to measure the thermal diffusivity

of the Ag nanoparticles on the biodiesel. The characteristic time constant was estimated by

fitting the experimental data to the theoretical expressions. The thermal diffusivity of the

biodiesel containing Ag nanoparticles nanofluids was strongly dependent on the presence of

the nanoparticles in the range of 0.01 to 0.1 % as concentration of nanoparticles increases. A

possible explanation of this phenomena is given.




281

[ PPP-361 ] Photothermal techniques for thermo-optical

characterization of mineral transformer oils

Andrés Marín Serrano ([email protected]) 2 , Primo Alberto

Calva Chavarría 2 , José Abraham Balderas López


1 IPN-UPIBI-Basic Science Department, Av. Acueducto S/N, col. Barrio la Laguna,

Ticomán, C. P. 07340, México, D. F., México 2 IPN-UPIITA-Posgraduate studies department, Av. Instituto Politécnico Nacional No.

2580, col. Barrio la Laguna, Ticomán, C. P. 07340, México, D. F., México

Photothermal techniques, in the sample´s thickenss scan domain, are presented for thermo-

optical characterization of mineral oils, used as dielectric fluids for power transformers.

Thermal diffusivity and optical absorption coefficient (at 405 nm) were measured for these

fluids, by means of a photopyroelectric and photoacoustic techniques, respectively, as a

function of the thermal degradation of these substances. Thermal diffusivity values were

found very closed to each other, independently of the degree of degradation of the oil,

meanwhile, optical absoprtion coeffcient values were found with enough difference as to be

considered as physical parameter for the assessment of the thermal degradation of these

substances.




282

[ PPP-375 ] Pulsed photoacoustic technique for the

characterization of gold nanoparticles formation by thermal

annealing thin films

Artemisa Mazón Martínez ([email protected]) 2 , Artemisa Mazón

Martínez 1 , Citlali Sánchez-Aké ([email protected]) 1 , Tupak

Ernesto García Fernández 3 , Mayo Villagrán Muniz 1

1 Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma

de México, P.O. Box 70-186, C.P. 04510, México D.F., México. 2 Facultad de Ciencias, Universidad Nacional Autónoma de México, Cd. Universitaria,

C.P. 04510, México D.F., México. 3 Universidad Autónoma de la Ciudad de México (UACM), Prolongación San Isidro 151,

San Lorenzo Tezonco, México D.F., C.P. 09790, México.

Gold nanoparticles (NPs) were produced by thermal annealing of Au films of different

thickness ranging from 20 to 40 nm. In this method, a dielectric substrate coated with a metal

thin film is heated up to below the metal fusion point. The NPs formation results from the

disaggregation of a film into particles due to the minimization of surface energy when the

temperature is increased [1]. The shape, mean size and size distribution of the NPs depend

on the film thickness, heating rate and the maximum temperature of the annealing process

[2].

In order to study of the evolution of the NPs formation we employed pulsed laser

photoacoustic technique, excited by a pulsed Nd:YAG laser. Our study was performed on

Au films deposited by sputtering on different dielectric substrates. Since the optical

absorption depends on the structure of the irradiated material, this technique may detect the

changes produced by the thermal annealing. The results obtained by photoacoustic were

compared with the corresponding sample images obtained by scanning electron

microscopy.

[1] C. Worsch, M. Kracker, W. Wisniewski, C. Rüssel, Thin solid films 520, 4941-4946,

2012.

[2] C.V. Thompson, Annu. Rev. Mater. Res., 42, 399-434, 2012.




283

[ PPP-378 ] Photoacoustic Techniques Applied to Thermo-

optical characterization of Biological Tissues.

Melisa Cuevas Sánchez 2 , Lilia Martínez Pérez 2 , José Abraham Balderas

López ([email protected]) 1

1 IPN-UPIBI, Av. Acueducto S/N, col. Barrio la Laguna, Ticomán, C. P. 07340, México, D.

F., México 2 IPN-UPIITA, Av. Instituto Politécnico Nacional No. 2580, col. Barrio la Laguna,

Ticomán, C. P. 07340, México, D. F., México

A self-normalized photoacoustic technique, in the modulation frequency domain, suitable for

thermo-optical characterization of sample sandwiched between transparent windows, was

applied for thermal diffusivity and optical absorption coefficient measurements (at 405 nm

and 532 nm) of biological tissues, embedded inside transparent glasses.

Biological samples consisted of rat skin tissues with progressive stage of melanoma. Thermal

diffusivity values for these samples were found very close to each other, for which this

thermal property was shown not quite adequate for health degree of these samples. Optical

absorption coefficients values (especially at 405 nm), on the other hand, shown adequate

differentiation as to be considered as promises physical parameter for classification of degree

of melanoma of these samples.




284

[ PPP-384 ] Relation between gas content and the thermal

diffusivity of mineral oils

Norma Angélica García Vargas ([email protected]) 2 , Primo Alberto

Calva Chavarría 2 , José Abraham Balderas López



F., México 2 IPN-UPIITA, Av. Instituto Politécnico Nacional No. 2580, col. Barrio la Laguna,

Ticomán, C. P. 07340, México, D. F., México

Results of a research of the relation between the thermal diffusivity coefficient and the

degradation level of mineral oils used as dielectrics in power transformers, particularly about

its gas content, are reported. To characterize the oil samples, dissolved gases analysis (DGA)

and photopyroelectric (PPE) technique were performed in order to obtain the dissolved gas

content and the thermal diffusivity coefficient, respectively. The analysis of the relation

between these properties showed up that the rise of the thermal diffusivity is attributed to the

presence of carbon monoxide and carbon dioxide. In the other hand, the dissolution of

acetylene presented a tendency of increasing the thermal diffusivity coefficient while its

concentration increased.




285

[ PPP-407 ] Electric field influence on heat transport in

aqueous dispersions of carbon nanotubes

F. Cervantes-Alvarez ([email protected]) 1 , J.D. Macías 1 , N. Pech-May

1 , J.J. Alvarado-Gil 1

1 Department of Applied Physics, CINVESTAV-Unidad Mérida, Carretera Antigua a

Progreso km.6, A.P. 73 Cordemex, C.P.97310, Mérida, Yucatán, México.

Carbon nanotubes are among the most interesting materials developed during the last few

years due to their outstanding thermal, electrical, and optical properties [1,2]. A good amount

of work has also been made in developing diverse composite materials based on carbon

nanotubes. In particular, they have attracted special interest for its large aspect ratio in

increasing the spatial scale of diverse phenomena. However applications in smart fluids

require that the nanotubes, immerse in a fluid matrix, can be manipulated. This can be done

using alternating electric fields which favor the formation of carbon nanotubes columnar

along the field and avoiding migration of the particles[3]. Those columnar arrangements

induce anisotropy which modifies reversibly the mechanical, optical and electrical properties

of the composite material.

In this work changes on heat transport of aqueous dispersions of multiwall carbon nanotubes,

with different concentrations, were characterized using infrared thermography. These

changes were investigated as a function of the applied electric field intensity.

[1] P.M.Ajayan, O. Stephan, C.Colliex, D.Trauth. Science 265, (1994)

[2] S.H. Hsu, M.C. Wu, S. Chen, C.M. Chuang, S.H. Lin, W.F. Su. CARBON 50, (2012)

[3] Oliva-Avilés A.I., Avilés F., Sosa V., Oliva A.I., Gamboa F. Nanotechnology 23 (2012).




286

[ PPP-467 ] Temperature dependence of biodiesel thermal

diffusivity

F. Cervantes-Alvarez ([email protected]) 1 , V.M. Chuc-Palacios 2 , L.

Díaz-Ballote 1 , M. Zambrano-Arjona 2 , J.D. Macías 1 , J.J. Alvarado-Gil 1

1 Department of Applied Physics, CINVESTAV-IPN, Carretera Antigua a Progreso km.6,

A.P. 73 Cordemex, C.P.97310, Mérida, Yucatán, México 2 Facultad de Ingeniería, Universidad Autónoma de Yucatán, Av. Industrias No

Contaminantes por Anillo Periférico Norte S/N, Cordemex, Mérida, Yucatán, México

Biodiesel is a renewable fuel option, it is made from vegetable oils or animal fats and it is an

alternative to replace fossil fuels. Biodiesel has the advantage of being biodegradable and

less pollutant than petroleum diesel but with similar characteristics. In order to know the way

in which the biodiesel would work in real conditions, it is of great interest to know its thermal

behavior as a function of temperature, in particular in the range around ambient temperatures

at which a given machine would start working. Biodiesels studied here were obtained through

the transesterification of soybean oil with ethanol, methanol and isopropanol respectively. In

this work thermal characterization of biodiesel was performed using the thermal wave

resonator cavity (TWRC) technique. Experiments were performed varying the thickness of

the cavity and also by performing modulation frequency scans. The behavior of heat transfer

was studied in the temperature range from 10 to 70 °C. Changes in temperature were induced

by modifying the conventional TWRC coupled with a Peltier cooling-heating cell. Results

show that the TWRC provides reliable results even when the biodiesels show higher thermal

transport stability. Also we found that the biodiesel thermal diffusivity presents a

decrement as the temperature rises.




287

[ PPP-485 ] Influence of heat losses at low frequencies in

photothermal experiments.

Kelly Martínez González ([email protected]) 1 , Ernesto Marín

Moares 1 , Enrique Cedeño Bernal ([email protected]) 1

1 Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología

Avanzada, Unidad Legaria, Legaria 694, Col. Irrigación, C.P. 11500, México D.F.,

México.

In this work experiments based in the photothermal infrared radiometry method and lock in

thermography have been designed for thermal diffusivity measurements in solids. Disc

shaped samples of different test materials were periodical heated at one of their surfaces at

different frequencies using an amplitude modulated laser beam, and the temperature at the

rear surfaces was monitored as a function of time using two kinds of infrared detectors: an

infrared thermometer and a thermography camera. Then, amplitude graphs as a function of

frequency were compared with a theoretical model with and without heat losses by

convection and radiation (CRHL) consideration. It has been found that for poor heat

conductors at low modulation frequencies the conventional model without CRHL does not

fit well the experimental data, while using the proposed model a good agreement was found.

From the fits of experimental data to the theoretical model the sample´s thermal diffusivities

(wood, plasticine, cork and polypropylene) have been obtained straightforwardly with a good

agreement in both experimental detection configurations. This work also demonstrates that

in photothermal experiments performed in frequency domain the CRHL must be taken into

account at low frequencies for poor heat conductors.




288

[ PPP-498 ] Subsurface microscopy of biased polycrystalline

silicon tracks: photothermal and thermo-reflectance images

Ernesto Rosales ([email protected]) 1 , A.M. Mansanares



Politécnico Nacional, Legaría 694. Colonia Irrigación 2 Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP. Cx.

P. 6165, 13083-970 Campinas, SP, Brazil.

Thermo-reflectance microscopy has been used the last decade as a suitable for the investigation of

micro- and opto-electronic devices in operating cycle. [1] It allows the determination of both heat

source distribution and heat propagation properties within specific regions of micrometer devices.

The technique is also useful for detecting and imaging defects. Besides the temperature field, it is

also sensitive to local electric field, [2] as well as to free-carrier density, which are in their turn

disturbed by defects. The noncontact and nondestructive character of the technique is one of its main

advantages. It enables aging tests, which are a necessary step in the development of electronic devices,

as well as progressive and repetitive treatment such as the application of voltage pulses intended to

simulate electrostatic discharge damaging. As a result device scaling in microelectronics,

interconnects have to tolerate higher current densities with a greater susceptibility to electro-

migration failure.

Electro-migration is the transport of material resulting the transfer of momentum the current

conducting electrons to the metallic ions. The geometry and the microstructure of the conducting

connection play an important role in electro-migration and on void formation [3].

High rate of heat generation (Joule dissipation) is associated with the high current density in such

interconnects. In addition to Joule dissipation, other heat sources in interconnects originate in

thermoelectric effects. Peltier effect was detected at the current modulation frequency f, while Joule

effect was measured by analyzing the signal at 2f. The electric current distribution is obtained by

using high modulation frequencies to avoid thermal broadening. In this manner, the signal distribution

is directly connected to the heat source distribution, which is, in turn, proportional to the square of

current density. By lowering the modulation frequency, the heat propagation in the structure is

observed in the results.

1. J.A. Batista, A.M. Mansanares, E. C. da Silva, and D. Fournier, J. Appl. Phys. 82, 423 (1997).

2. G. Tessier, G. Jerosolimsky, S. Hole, D. Fournier, and C. Filloy, Rev. Sci. Instrum.. 74, 495 (2003).

3. A. Ghiti and A. G. O’Neill. “The effect of grain boundary diffusion anisotropic on via

electromigration failure.” J.Appl. Phys 81 (7), 3064-3068 (1997)




289

[ PPP-503 ] RTA crystallization of unhydrogenated

amorphous silicon thin films deposited by rf sputtering system

Abraham Pacio ([email protected]) 1 , Hector Juarez 1 , Xavier

Mathew 4 , Nicolas Budini 3 , Mauricio Pacio 1 , Cesia Guarneros 2 , Jose

Alegandro Garcia 5

1 Centro de Investigación en Dispositivos Semiconductores, Benemérita Universidad

Autónoma de Puebla, 14 Sur y Avenida San Claudio, San Manuel C.P. 72570, Puebla,

México 2 Instituto Politécnico Nacional, CICATA- Altamira, Km 14.5, Carretera Tampico-Puerto

Industrial Altamira, 89600 Altamira, Tamaulipas, MÉXICO 3 Instituto de Física del Litoral (UNL-CONICET), Güemes 3450, S3000GLN Santa Fe,

Argentina. 4 Instituto de energías Renovables Universidad Nacional Autónoma de México, Temixco,

Morelos 62580, México. 5 Preparatoria "Gral. Lázaro Cárdenas del Río", BUAP, 4 Oriente 412 y 414 Col. Centro,

Puebla, México

We present results regarding the morphological and electrical characterization of

semiconductor junctions formed by deposition of n-type amorphous silicon (a-Si) thin films

in a small-scale rf-sputtering pilot system. The amorphous silicon is a material which is

deposited by means of RF sputtering technique. This system carried out deposits of thin films

inside of an argon atmosphere. The thickness of the film can be controlled varying the deposit

pressure, RF power, and target-substratum distances. The amorphous silicon films deposited

by means of RF sputtering technique were prepared with the RF power of 40 Watts, the

pressure into the camera was modified varying the argon flow to obtain a pressure of 1.2 x

10-2 torr, and varying the deposition temperature of 200 to 600 ° C. We control the thickness

of the amorphous silicon films through the deposit pressure and RF power. These parameters

control the energy necessary for remove the atoms in the target, and deposit on the substrate

surface. The film thickness is 100 to 200 nanometers. The amorphous silicon films were

annealing at 900ºC to 1000°C to achieve a complete crystallization by rapid thermal

annealing (RTA). This increase the conductivity and the size crystal grain to obtain a high

mobility of energy to cross the films. Those parameters make possible application in solar

cells. The crystallization evolution was observed in reflectance UV-vis, Raman spectroscopy,

optical microscopy and electrical properties. This increase the conductivity and the size

crystal grain to obtain a high mobility of energy in the films. Those parameters make possible

application in solar cells. The crystallization evolution was observed in reflectance UV-vis,

Raman spectroscopy, optical microscopy, X-ray diffraction and electrical characterizations.




290

[ PPP-506 ] Photoacoustic tecnhique, in the modulation

frequency domain, for thermo-optical characterization

José Balderas López ([email protected]) 1


F., México

Photoacoustic technique, in the modulation frequency domain, for thermal and optical

characterization of samples is presented. The analytical scheme involves a self normalized

procedure which consist in taking the complex ratio of photoacoutic signal in the

transmission and front configurations. This procedure was applied to aquous solutions of

methylene blue, at different concentrations, for obtaining their optical absorption coefficients

(at 660 nm) and black china ink, for obtaining its thermal diffusivity. Excellent agreement

with reported values was obtained, showing that the presented self-normalization procedure

its adequate for optica absorption measurements for high concentrated samples.




291

[ PPP-527 ] Lock-in CCD Camera Photothermal Beam

Deflection Tracking

Angel Cifuentes ([email protected]) 1 , Angel Cifuentes 2 ,

Salvador Alvarado 1 , Humberto Cabrera 3 , Humberto Cabrera 1 , Ernesto

Marín 1


Politécnico Nacional, Legaria 694. Colonia Irrigación, 11500 México D. F. 2 Departamento de Fisica Aplicada I, Escuela Superior de Ingenieros, Universidad del País

Vasco, c/ Alameda Urquijo s/n, 48013 Bilbao, España. 3 International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste, Italy

and Centro Multidisciplinario de Ciencias, Instituto Venezolano de Investigaciones

Científicas, IVIC, Mérida 5101, Venezuela

Photothermal beam defection is a well-established technique for measuring thermal

diffusivity of certain samples such as thin films and filaments [1]. In this technique, an

excitation beam generates temperature variations on the surface of the sample to be studied.

These variations transfer heat to the surrounding medium, which may be air or any other

fluid. The medium in turn suffers a change in the refraction index, which will be proportional

to the temperature field on the sample surface when the distance to this surface is small. The

refraction index can be probed by means of a laser beam, which will suffer a deflection,

which in turn will be proportional to the induced sample surface temperature variation. If

certain experimental conditions are met, a horizontal distance sweep, i.e. parallel to the

sample surface, will reveal the thermal diffusivity through simple linear relations [2].

The traditional experiment uses some kind of photo detector, e.g. Quadrant Photo-diode, and

some means of amplification, e.g. Lock-in amplifier. Here we present a detection scheme in

which a HD CCD camera substitutes all detection hardware utilizing motion detection

techniques and software digital signal post-processing.

1. A. Mendioroz, R. Fuente-Dacal, E. Apiñaniz, A. Salazar.ev. Sci. Instrum., 80, 074904

(2009).

2. A. Salazar, A. Sánchez-Lavega. Rev. Sci. Instrum., 65, 2896 (1994).




292

[ PPP-558 ] Monitoring and treatment of 2D and 3D optical

images applied to photothermal techniques using a low cost

camera and computer software

Juan Ignacio Escorza Chávez 2 , José Luis Jiménez Pérez

([email protected]) 2 , Zormy Nacary Correa Pacheco 1 , Jessica

Morales Vanegas 3

1 Instituto Politécnico Nacional-Centro de Desarrollo de Productos Bióticos. Carretera


Laguna Ticomán, 07340. México D.F. 3 UPVM, Avenida Mexiquense S/N, Esquina Universidad Politécnica, Col. Villa Esmeralda,

Tultitlán, Edo. México, Ticomán, C.P. 54910.

In this work, a computer program for the treatment of 2D and 3D images using a low-cost

CMOS camera, with the aim of developing an optical instrument for measuring Gaussian

laser beam profiles was developed, in order to provide a platform for the geometric

parameters associated with it, without the high costs associated with commercial equipment.

Once the instrument was designed and built, experimental profiles were obtained by the

method of knife edge and compared with those obtained by our image treatment system with

the experimental and theoretical 2D resulting good quantitative and qualitative agreement

between both methods. In this work, the results were applied for the measurement of laser

waist much more quickly and easily when the traditional method was applied. These

experiments can be widely used in the thermal lens spectrometry to determine the thermal

properties of some fluids.




293

[ PPP-570 ] Thermal effusivity determination in mucin-

protein blends by using a photoacoustic configuration

Azucena López-López 1 , Emma Gloria Ramos-Ramírez 1 , Margarita

Lizbeth Alvarado-Noguez 2 , Alfredo Cruz-Orea 2 , Juan Alfredo Salazar-

Montoya ([email protected]) 1

1 CINVESTAV-IPN. Department of Biotechnology and Bioengineering 2 CINVESTAV-IPN. Department of Physics

Mucins are high molecular weight glycoproteins, heavily glycosylated containing water,

salts, and lipids constituting mucous secretions covering surfaces of the digestive, respiratory

and reproductive systems in mammals. Interactions of this glycoprotein are of great

importance because of the protection functions they play in the gastric system and the recent

interest in the study of blends with proteins. Thermal effusivity of materials defines the ability

to exchange heat with the environment and is related to other thermo-physical properties such

as thermal conductivity, thermal diffusivity, specific heat and density among others. The aim

of this study was to determine the thermal effusivity, by using photoacoustic configuration(1),

of blends of crude and purified mucins, with soy protein and gelatin, mixed in the ratio 1:1.

The obtained results showed values from 1470 to 2670 . The obtained

thermal effusivity values in mucins-gelatin blended are closed to the water thermal effusivity

value.

Reference

(1) Balderas-López, J. A., Gutiérrez-Juárez, G., Jaime-Fonseca, M. R. and Sánchez-Sinencio,

F. 1999. Measurements of thermal effusivity of liquids using a conventional photoacoustic

cell. Review of Scientific Instruments, 70, 2069-2071.




294

RENEWABLE ENERGY: SOLAR

CELLS AND MATERIALS (RWE) Chairman: Guillermo Santana (IIM-UNAM)

Oral Session

[ RWE-20 ] New about the solar cells

Igor Volovichev 1 , Yuri Gurevich ([email protected]) 2

1 A.Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of

Ukraine, 12 Ac. Proscura St., Kharkov 61085, Ukraine 2 Departamento de Fisica, CINVESTAV-I.P.N., 2508, Apartado Postal 14-740, Mexico

D.F. 07000, Mexico

The interplay between physical reasons of nonequilibrium in a steady state and their influence

on the linear transport processes in bipolar semiconductors is under investigation. Particular

attention is paid to the influence of the energy nonequilibrium on the generation-

recombination processes at various semiconductor parameters. It is shown that in the case of

a spatially inhomogeneous, but a single temperature of the charge carriers and phonons, the

volume recombination rate of the charge carriers in the steady state is completely determined

by the splitting of the quasi-Fermi levels.

Particular emphasis has been placed on the manifestation of the energy nonequilibrium in the

presence of hot charge carriers in a semiconductor. It is shown that in this case the generation-

recombination balance shifts, being completely equivalent to the appearance of an additional

external generation of the electron-hole pairs. The two-temperature model (with electron

temperature being different from the equal hole and phonon temperature) of the Dember

photovoltaic effect is used to illustrate that the electromotive force (emf) may differ

significantly from its corresponding values with no hot electrons. This additional contribution

to the emf depends on neither the Seebeck coefficient nor the temperature gradient and the

electron-hole pair generation rate, being solely determined by the level of the electron

subsystem heating.




295

[ RWE-66 ] Autocatalytic silver coatings with protective

transparent films for solar concentrators

José de Jesús Pérez Bueno ([email protected]) 1 , Monserrat Gutiérrez

Muñoz 1 , Yunny Meas Vong 1 , Guy Stremsdoerfer 2 , Monserrat Gutiérrez

Muñoz 2

1 Centro de Investigación y Desarrollo Tecnológico en Electroquímica, S.C. Parque

Tecnológico Querétaro s/n Sanfandila, Pedro Escobedo, Qro., México. 76703. 2 Laboratory of Tribology and Dynamics of the Systems UMR 5513 Ecole Central de Lyon.

36 Avenue Guy de Collongue B P 163 69131, Ecully Cedex, France.

In concentrating solar power (CSP) is important to find coatings with high transmittance

values (greater than 90%) to protect the reflective materials. These transparent coatings

require to be inexpensive and maintaining their optical properties for extended lifetimes

under outdoor environments. In this work; organic, inorganic and hybrid coatings were made

on highly reflective silver (about 94%) [1], which was deposited by the Dynamic Chemical

Plating technique (DCP) on polymer substrates. The coatings obtained comply with the

optical characteristics required and were evaluated over time under UV exposure. Also, in

this study it was determined which of the different types of coatings increased durability,

efficiency, and had the best features for solar concentrators. Silver deposit obtained by DCP

technique show a uniform silver film with an average roughness of 8.69 nm.




296

INVITED TALK [ RWE-85 ] Influence of growth conditions in the morphology

and luminescence of CdS nanowires

Osvaldo de Melo ([email protected]) 5 , Osvaldo de Melo 2 , Patricia G. Zayas-Bazán 5 ,

Karla Gutiérrez Z-B 5 , Karla Gutiérrez Z-B 2 , Guillermo Santana 3 , Jaime Santoyo-Salazar

1 , Josue Esau Romero-Ibarra 4 , Gerardo Contreras-Puente 2

1 Departamento de Física, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, CINVESTAV-IPN, A.P. 14-740, México D.F. 07360, México

2 Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Unidad Profesional

“ALM”, México D.F. 07738, México 3 Instituto de Investigación en Materiales, Universidad Nacional Autónoma de México, Cd.

Universitaria, A.P. 70-360, Coyoacán 04510, México D. F 4 Laboratorio Avanzado de Nanoscopía Electrónica, Centro de Investigación y Estudios Avanzados

del IPN, CINVESTAV-IPN, A.P. 14-740, México D.F. 07360, México 5 Physics Faculty, University of Havana, 10400 La Habana, Cuba

Preparation of 1D semiconductor nanostructures has been strongly developed in recent years. This is

because they boast important applications at the nanoscale comprising sensors,[1],[2] 3rd generation

solar cells,[3],[4] photodetectors[5] and lasers.[6] In particular, it is expected that nanowires (NWs)

of CdS, an important n-type II-VI semiconductor typically used as window in thin film solar

cells[7],[8] would greatly rise the area of the absorber material in these devices. At the same time,

reflection losses and photo- excited carrier mean free paths could be reduced with a consequent

increase in efficiency.

In this work, CdS nanowires (NWs) were prepared by the catalytic method using Au coated GaAs

and Si substrates. Scanning and transmission electron microscopy techniques (SEM, TEM) allowed

observing the morphology and structure of the nanowires as a function of the growth conditions. It

was observed that nanowires grown onto Si substrates present larger diameters and smaller lengths

than those growth on GaAs ones. It can be related to the different properties of liquid eutectic in each

case and to the transport of the species not only though the liquid drop. The NWs show very brilliant

photo-luminescence (PL) even at RT. PL spectra as a function of temperature were analyzed and

related with the morphology features.

([1]) U. Yogeswaran; S. M. Chen, Sensors 2008, 8, 290-313.

([2]) F. Patolsky, Ch. Lieber, M. Materials Today, 8, 2005, 20-28.

([3]) E. C. Garnett, M. L. Brongersma, Y. Cui, M. D. McGehee, Annu. Rev. Mater. Res. 2011, 41,

269-295.

([4]) M. Law, L. E. Greene, J. C. Johnson,; R. Saykally, P.Yang, Nature Mater. 2005, 4, 455-459.

([5]) H. Kind,; H. Yan,; B. Messer, M. Law, P. Yang, Adv. Mater. 2002, 14, 158-160.

([6]) M. H. Huang, S. Mao, H. Feick, H. Yan, Y. Wu, H. Kind, E. Weber, R. Russo, P. Yang, Science

292, 8, 2001, 1897-1899.




297

([7]) N. Romeo, A. Bosio, V. Canevari, A. Podestá, Sol. Energy 2004, 77, 795-801

([8]) M. G. Mahesha, K. V. Bangera, G. K. Shivakumar, Mat. Sci. Semicon. Proc. 2009, 12, 89-93

[ RWE-281 ] Towards a high efficiency silicon solar cells based

on low cost c-Si CZ wafers

Mario Moreno ([email protected]) 2 , José de Jesús Martínez 2 , Pedro Rosales

2 , Alfonso Torres 2 , Dulce Murias 2 , Roberto Ambrosio 1 , Claudia Reyes-Betanzo 2 , Israel Vivaldo 2

1 Benemérita Universidad Autónoma de Puebla, BUAP, Facultad de Electrónica 2 Instituto Nacional de Astrofísica, Optica y Electrónica, INAOE

In this work we present the development of crystalline silicon (c-Si) solar cells with efficiencies up

to 13%, fabricated on low cost CZ c-Si wafers. In order to develop a low cost fabrication process we

are using as dopant source Spin On Dopant (SOD) for the solar cell emitter formation. The use of

SOD simplifies the solar cell fabrication process, avoiding the use of dopant gases sources, which

reduces the complexity of the atomic diffusion furnace and also increment the safety of the fabrication

process, avoiding the use of toxic gases.

The c-Si solar cells were fabricated on 300 μm, boron doped (5-15 Ωcm) low cost Hydroxide (KOH),

deionized water and isopropyl alcohol (IPA). The cell emitter was formed by diffusion of

phosphorous from a SOD source at 950°C, for 10 minutes (this process was also optimized). A 100

nm thick silicon dioxide (SiO2) film was deposited by CVD at 350 °C and was used as a single layer

antireflection coating (SLARC). The formation of the upper contact was made with one

photolithography step in order to open windows in the SiO2 film and depositing a 0.5 µm thick

aluminum grid. Finally, the bottom contact was formed by 5 µm thick aluminum deposition, followed

by a thermal annealing at 500 °C.

Measurements of the junction depth and doping profile of the solar cells were made by the

electrochemical capacitance-voltage technique, while the solar cells characterization was made under

standard terrestrial testing conditions (AM1.5, 100 mW/cm2) using the Newport Oriel Sol 2A solar

simulator. The cell efficiency obtained by this process for a solar cell of area of 100 mm2 is of 13%.

Although the solar cell efficiency reported in this work is still low in comparison with that of high

efficiency solar cells, it is important to stress that the reported device was fabricated using a simple

structure (that can be industrially compatible) on a Czochralski (CZ) wafer, which has lower minority

carriers bulk life time (about four times) and also is much more un expensive (more than five times)

than a Float Zone (FZ) wafer, used for higher efficiency solar cells.

Moreover, for increase the efficiency of the solar cells reported in this work, several processes must

be improved yet, as the surface passivation in order to increase the open circuit voltage (Voc). And

as well, the formation of a suitable Back Surface Field (BSF) in the cell back contact using serigraphy

techniques, in order to reduce the series resistance and consequently improve the fill factor.




298

[ RWE-317 ] CHEMISORPTION AND REPULSION

ENERGIES OF Mg1-xNixH ALLOYS (0 ≤ x ≤ 0.1)

G. Ramírez-Dámaso ([email protected]) 3 , G. Ramírez-Dámaso 4 , I. E.

Ramírez-Platón ([email protected]) 3 , F. L. Castillo-Alvarado 2 , E.

Rojas-Hernádez 3 , A. Valencia-Islas 3 , F. L. Castillo-Alvarado 1

1 Becario COFAA-IPN, EDD-IPN. 2 Escuela Superior de Física y Matemáticas del IPN, Av. Instituto Politécnico Nacional s/n,

Unidad Profesional Adolfo López Mateos, Edificio 9, col. Lindavista, Del. Gustavo A.

Madero, Distrito Federal, C. P. 07738, México. 3 Escuela Superior de Ingeniería y Arquitectura “Unidad Ticomán” del I. P. N., Av.

Ticomán No. 600, Col. San José Ticomán, C. P. 07330, Del. G. A. M., México D. F.,

México. 4 Tecnológico de Estudios Superiores de Ecatepec, Av. Tecnológico s/n esq. Av. Carlos

Hank González, Col. Valle de Anáhuac, C. P. 55210, Ecatepec Edo. de México, México .

In this work we use Density Functional Theory (DFT) to calculate geometry optimization of

Mg1-xNix, for x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1. Hydrogen molecules on the surface (110)

of Mg1-xNix are introduced to obtain the Mg1-xNix-H alloy and calculate their geometry

optimization, enthalpy, density of states, energies of chemisorption and energies of repulsion

with hydrogen on his surface. Results of most stable x concentration of atoms of nickel for

hydrogen storage of these alloys are presented. We used generalized gradient approximations

(GGA) in CASTEP module, of the molecular simulation program Materials Studio 6.0, to

obtain our results.




299

[ RWE-424 ] Position of the maximum value of the exciton-generation

profile within the active layer of organic solar cells.

Omar Ramírez Sánches ([email protected]) 1 , Víctor Cabrera Arenas

([email protected]) 1 , Luis Martín Reséndiz Mendoza 1

1 Instituto Politécnico Nacional-UPIITA-SEPI, Avenida IPN 2580, La Laguna Ticomán,

Del. Gustavo A. Madero, México, 07340, MX

Organic solar cells have demonstrated to be attractive due to their advantages in terms of low

cost, easy manufacturing, lightness and compatibility with flexible substrates. In order to

improve the efficiency, several optical analysis based on the transfer matrix formalism have

been performed to determine optimal light absorption. It has been reported that the

absorption efficiency can be enhanced by using an optical spacer which could shift the

position of the maximum optical electric field into the photoactive layer. However, these

works normally present the influence of that layer on the exciton-generation profile based on

many calculations for different thicknesses. In this work, we analyzed the second subsystem

of the transfer matrix method and found that a simple cosine function can be used to

determine the position of the maximum value of the exciton-generation profile. We also

found that the function suffers a displacement from the reflecting electrode given by a phase

shift that depends on the complex refraction index and the thickness of the metallic contact,

optical spacer and photoactive layer.




300

INVITED TALK [ RWE-567 ] Selecting CdS:F or CdS:O for window layer application in

CdTe-based solar cells.

Juan Luis Peña Chapa ([email protected]) 1 , Eric Noé Hernández

Rodríguez 1 , Ricardo Mis Fernández 1 , Víctor Rejón Moo 1

1 Applied Physics Department, CINVESTAV-IPN, Apdo. Postal 73, Mérida, Yucatán,

97310, México

In this work CdS:F and CdS:O thin films were studied. Films were prepared by the RF-

sputtering technique in an atmosphere containing Ar mixed with CHF3 or O2 reactive gases.

XPS measurements showed that CdS:F films are composed by CdS and CdF2 while CdS:O

comprises the CdS, CdSO4, CdSO3 and CdO2 compounds. Modulation of optical properties

was achieved by changing the reactive gas concentration during deposition. According to the

transmittance, bandgap and refractive index values, it was concluded that CdS:O thin films

are more suitable for window layer application. This work has been supported by

CONACYT-SENER (México) under project CeMIE-Sol 207450/P25.




301

Sesión Poster

[ RWE-17 ] Alcoholic fermentation kinetics of sugars obtained from

Agave tequilana Weber Azul leaves using Klyveromyces marxianus and

Saccharomyces cerevisiae for the second generation ethanol.

Jorge Carlos Avila Gaxiola ([email protected]) 2 , Maria Elisa Evangelina Avila

Gaxiola ([email protected]) 2 , Lorena Amaya Delgado 1 , Javier Placido

Arrizon Gaviño 1 , Jesus Cervantes Martinez 1 , Oscar Jesus Velarde Escobar 2 , Francisco

Ramos Brito 2 , Gelacio Atondo Rubio 2 , Cristo Manuel Yee Rendon 2 , Maria Elisa

Evangelina Avila Gaxiola 3

1 Centro de investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco. Unidad de

Biotecnología Industrial. Av. Normalista, Col. Colinas de la Normal, Guadalajara, Jalisco, México 2 Facultad de Ciencias Físico – Matemáticas, Universidad Autónoma de Sinaloa. Av. de las

Américas y Blvd. Universitarios, Cd. Universitaria, Culiacán, Sinaloa, México 3 Facultad de Ciencias Químico-Biológicas, Universidad Autónoma de Sinaloa. Av. de las Américas

y Blvd. Universitarios, Cd. Universitaria, Culiacán, Sinaloa, México

Recent investigations of second generation biofuels focus on developing new alternative energy, but

are equally important that it does not threat food supplies. The use of agricultural waste has become

an attractive source for biomass that could be converted into new energy sources. The present work

proposes the use the waste of the tequila industry specifically the leaves of the Agave tequilana Weber

Variety Azul as source for biomass. We have found the best conditions for extraction of sugars, for

enzymatic hydrolysis of fructans and for acid-enzymatic hydrolysis of the lignocellulosic material

contained in agave leaf for the release of reducing sugars (RS) used in the obtention of ethanol. The

substrate used was obtained by mixing all extracts of reducing sugars (34 g/L) generated in previously

pretreatment that we have already reported. The objective is to evaluate yield of ethanol, the

consumption of the substrate and cell growth using two different yeast: Saccharomyces cerevisiae

and Klyveromyces marxianus. The fermentation process (under a pH 4.5, 30 ° C and at 100 rpm) of

the agave leaf substrate was conducted in a kinetic with times of 3, 6, 12, 18, 24, 30, 36, and up to 42

hours. Cell growth was determined by cell counting method, the ethanol and sugar content at each

time of fermentation was determining using techniques of high resolution liquid chromatography, gas

chromatography and Raman spectrometry. The fermentation kinetic study allowed us to determine

that best production of ethanol for both yeast was a time of 18 hours. Ethanol production with K.

marxianus (11.9 ± 0.2 g/L) was higher compared to S. cerevisiae (10.6 ± 0.3 g/L). During

fermentation, the yeasts was able to assimilate the substrate because achieved consume 86% of the

initial concentration of RS. The ethanol yield obtained with K. marxianus (0.41 g ethanol / g RS) was

better with respect to S. cerevisiae (0.36 g ethanol / g RS) yeast. These results show that the substrate

of sugar obtained from the agave leaf is a suitable alternative and promising to produce ethanol using

both yeasts studied.




302

[ RWE-52 ] A hydrogen study from films to structures for

stable pm-Si:H solar cell devices

Leon Hamui ([email protected]) 1,2 , B. Marel Monroy 2 , Jaime

Santoyo-Salazar 1 , Guillermo Santana 2

1 Departamento de Física, Centro de Investigación y de Estudios Avanzados, A.P. 14-740,

Gustavo A. Madero, México, D.F. 2 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México.

A.P. 70-360, Coyoacán, C.P. 04510, México, D.F.

In the last years hydrogenated amorphous silicon (a-Si:H) has been the thin film base material

for the manufacturing of large area electronic devices such as solar cells. Various techniques

have been used to optimize plasma enhanced processes to manufacture hydrogenated

amorphous silicon PIN and NIP devices, but a light-induced degradation referred to as the

Staebler–Wronski Effect (SWE) is presented. Thus, Hydrogenated polymorphous silicon

(pm-Si:H), which consists of nanocrystals embedded in an amorphous matrix, shows greater

stability under illumination, better electronic properties and lower defect density than a-Si:H

which is attractive for solar cells applications. However, the hydrogen bonding configuration

can be more complex since hydrogen can be found in the amorphous matrix and in the

nanocrystalline/amorphous interface. Therefore, pm-Si:H is studied in order to understand

the effect of the growth parametres on pm-Si:H films, hydrogen bonding and stability were

analyzed in this work. HRTEM images evidence nanocrystals with approximate size of 9 nm.

A growth surface reorganization was observed. The optoelectronic properties of the films are

directly related to the incorporation of hydrogen and whether it is weakly or tightly bonded.

A diminution of the optical gap of the pm-Si:H films in the range from 1.71 to 1.65 eV was

observed. Furthermore, PIN and NIP structures were studied trying to determine the effect

of light-soaking pre-treatments on the hydrogen effusion mechanisms related to the

hydrogen stability and its evolution during exodiffusion. We examined the structural and

optical properties of PIN and NIP structures after exodiffusion experiments. Also, an analysis

of both structures was done in order to determine which one is less affected by light-soaking.

We show that long range motion of hydrogen during light-soaking and annealing causes a

hydrogen rearrangement on the film and microstructure changes which result in a shift on the

exodiffusion peaks. We determined that for the PIN structure a hydrogen diffusion barrier is

generated by light-induced defects, which is expected to cause less degradation of its

optoelectronic properties under illumination in solar cell applications.




303

[ RWE-72 ] Optimization geometry and density of states in

bulk and surface (110) Mg1-xNix alloys

G. Ramírez-Dámaso ([email protected]) 4 , I. E. Ramírez-Platón

([email protected]) 3 , E. Rojas-Hernádez 3 , F. L. Castillo-Alvarado 2 ,

A. Valencia-Islas 3 , C. E. Hernández-Olguín 3 , G. Ramírez-Dámaso 3 , F. L.

Castillo-Alvarado 1

1 Becario COFAA-IPN, EDD-IPN. 2 Escuela Superior de Física y Matemáticas del IPN, Av. Instituto Politécnico Nacional s/n,

Unidad Profesional Adolfo López Mateos, Edificio 9, col. Lindavista, Del. Gustavo A.

Madero, D.F., C. P. 07738, México. 3 Escuela Superior de Ingeniería y Arquitectura “Unidad Ticomán” del I. P. N., Av.

Ticomán No. 600, Col. San José Ticomán, C. P. 07330, Del. G. A. M., México D. F.,

México. 4 Tecnológico de Estudios Superiores de Ecatepec, Av. Tecnológico s/n esq. Av. Carlos

Hank González, Col. Valle de Anáhuac, C. P. 55210, Ecatepec Edo. de México, México .

ABSTRACT

In the past two decades, metal hydride has been studied as an alternative for hydrogen storage

in metals. In this work we study Magnesium in alloy with Nickel, selecting concentrations

of nickel between 0.0 and 0.08. We use Density Functional Theory to optimize the geometric

structure hcp of a crystal of MgNi, to determine the density of states and their total enthalpy.

We use CASTEP of the molecular simulation program Material Studio 6.0, to build the

crystal structure of the bulk alloy Mg1-xNix (for x=0.02, 0.04, 0.06 and 0.08). Then we cleave

bulk Mg1-xNix to build the surface in the direction of the plane (110), and then we introduce

hydrogen molecules to interact on that surface. With our program of molecular simulation,

we optimize the crystal structure of these surfaces with and without hydrogen. Finally we

analyze the results of the geometrical optimization, the density of electronic states (PDOS),

as well as the total energies both on the bulk and on the surface (110) with hydrogen.




304

[ RWE-126 ] Kinetic study of fermentable sugars released

during the enzymatic hydrolysis of lignocellulosic material

present in the leaves of Agave tequilana Weber variety blue as

a biomass source for second generation biofuel.

Maria Elisa Evangelina Avila Gaxiola ([email protected]) 2

, Jorge Carlos Avila Gaxiola 2 , Lorena Amaya Delgado 1 , Oscar Jesus

Velarde Escobar 2 , Francisco Ramos Brito 2 , Gelacio Atondo Rubio 2 ,

Cristo Manuel Yee Rendón 2

1 Biotecnología Industrial, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado

de Jalisco, Av. Normalista, Col. Colinas de la Normal, Guadalajara, Jalisco, México. 2 Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Sinaloa, Av. de las Américas

y Blvd. Universitarios, Cd. Universitaria, Culiacán, Sinaloa, México.

Second generation biofuels are developing as an attractive alternative to fossil fuels with the aggregate

value that does not compete with the food chain production Common source for second generation

biofuels are the agricultural waste. The present work proposes the use the waste of the tequila industry

specifically the leaves of the Agave tequilana Weber variety Blue as a promising source of biomass

for biofuel production.

Lignocellulosic biomass is inexpensive, renewable and abundant source for ethanol production. In

the world many studies are focus in the conversion of lignocellulosic biomass to ethanol, using

physical, chemical and/or enzymatic treatment for the production of sugars for subsequent alcoholic

fermentation. The objective of this work is to study the kinetics of the release of fermentable sugars

during the enzymatic hydrolysis of lignocellulosic biomass agave leaf.

The enzymatic hydrolysis were performed using three commercial enzyme Celluclast, Viscozyme

and Cellic CTec-2 and was monitored from 6 to 24 hours. The reducing sugar obtained at each time

of enzymatic reaction were determined by the method photocolorimetric 3,5-dinitrosalicylic acid

(DNS) at 540 nm, techniques of high resolution liquid chromatography and Raman spectrometry.

The kinetic study allowed us to determine the best enzyme in for releasing sugars in the

lignocellulosic biomass of the agave leaves was Cellic CTec-2. The enzyme Cellic CTec-2 achieving

maximum release of reducing sugar (33.5 ± 1.0 g / L) at 18 hours of reaction. The yield of enzymatic

hydrolysis was 88%. From the results is conclude that the enzyme is compatible with lignocellulosic

biomaterial and that the agave leaf is alternative biomass for the production of second generation

ethanol.




305

[ RWE-154 ] Vacuum free deposition of Cu2ZnSnS4 films

using nanoparticle based paste and their characterization

Antonio Aguilar García ([email protected]) 1 , Enrique

Quiroga González 3 , Julio Villanueva-Cab 3 , Nini Rose Mathews 2 , Mou

Pal ([email protected]) 3

1 Facultad de Ciencias de la Electrónica, BUAP, Ciudad Universitaria, Puebla, México 2 Instituto de Energías Renovables, Universidad Nacional Autónoma de México, 62580

Temixco, Morelos, México 3 Instituto de Física, BUAP, Av. San Claudio y Blvd. 18 Sur Col. San Manuel, Ciudad

Universitaria, C.P. 72570, Puebla, México

The Cu2ZnSnS4 (CZTS), a nontoxic and earth abundant chalcogenide semiconductor, has

been emerged as an alternative to the conventional absorber layers such as CdTe and

CuInGaSe2 (CIGS) in thin film solar cells. In the present work, the CZTS nanoparticles were

synthesized by a solvothermal method with and without using polyvinylpyrrolidone as a

surfactant. The crystal structure, morphology, chemical composition, and optical band gap

of the NPs were evaluated by X-ray diffraction, Raman spectroscopy, scanning electron

microscopy, energy-dispersive X-ray spectroscopy and UV-Vis-near IR spectroscopy. The

formation of kesterite phase was confirmed by XRD and Raman results. The band gap of the

nanoparticles was determined to be 1.5 eV which is suitable to be used in solar cell

applications. A paste of CZTS was made using the NPs and was painted on soda lime glass

substrate by doctor blading method. The films were annealed at 500 0C for 1 h in N2/S

atmosphere and the structural and optical properties were further characterized to confirm

the phase purity of the annealed films. The films were found to be photoconductive. Further

detailed electrical characterization is under progress.

Acknowledgements: Authors acknowledge Dr. Ricardo Agustín Serrano, Carla de la Cerna

Hernández and Eric Reyes Cervantes of CUVyTT (Centro Universitario de Vinculación y

Transferencia de Tecnología), BUAP for their assistance in XRD, SEM and EDS

measurements. This work was partially supported by the project VIEP, BUAP Grant #

VIEP/EXC/2015, Mexico.




306

[ RWE-204 ] Thin films of CdTe nanocrystals grown by

chemical synthesis

Enrique Campos Gonzalez ([email protected]) 2 , Francisco de

Moure Flores 1 , Jaime Santoyo Salazar 2 , Claudia Jaramillo Torres 4 ,

Lorena Eugenia Ramírez Velázquez 4 , Gerardo Contreras Puente 3 ,

Orlando Zelaya Angel 2

1 Department of Chemistry, Universidad Autónoma de Querétaro, Querétaro, México 2 Department of Physics, Centro de Investigación y de Estudios Avanzados del IPN. P.O.

Box 14-740, México 07360 D.F. 3 ESFM, Instituto Politécnico Nacional, México D.F., México. 4 ESIQIE, Instituto Politécnico Nacional, México D.F., México

By means a chemical synthesis technique thin films of stoichiometric CdTe nanocrystals

were prepared on glass substrates in the range 55 – 70 °C of temperature. The layers grow in

the cubic zincblende crystalline phase with no preferred orientation. Firstly, Cd(OH)2 films

were deposited on glass substrates, after, these films were immersed in a growing solution

prepared by dissolution of Te in hydroxymethane sulfinic acid to obtain CdTe. In scanning

electron microscopy images the surface of the layers looks even with a granular aspect which

indicates that nanocrystals grow giving place to clusters. The average size of nanocrystals

lies in the range 6.0 – 12.0 nm and the thickness of the films is in the interval 50 – 100 nm.

Raman spectroscopy reveals the LO phonon mode and the first overtone of the CdTe

semiconductor. In general, the analysis of the CdTe films indicates that the material have

good structural and optical properties to be used in terrestrial solar cells preparation.




307

[ RWE-239 ] Quantum Dots and Solar Cells

Arezbith Camarillo Sifuentes ([email protected]) 1 , David

Armando Contreras Solorio ([email protected]) 1

1 Academic Unit of Physics, Autonomous University of Zacatecas, Lomas del Patrocinio,

Zacatecas, Zac. 98060

It appeared last year the report promoted by Obama: Climate Change Impacts in the United

States. This is a contribution of more than 300 experts and the report points out unequivocally

that the the climate is changing due to a global warming more pronounced these last 50 years.

This global warming is caused by the human activity, essentially by the use of fossil fuels

and the colateral emission of greenhouse gases, mainly carbon dioxide. It is then imperative

to increase the use of renewable energies like that of photovoltaic. A limiting factor is that

the electricity produced by solar cells is still relatively expensive. It is crucial to improve

their efficience, which measures how much of the energy received from the Sun, is

transformed to electricity. For semiconductor solar cells the bandgap is very important for

their efficiency. The ideal bandgap is around 1.3-1.4 eV. A way very promising to improve

the efficiency, is the usage of cells based on quantum dots because their bandgap depends on

the size, which can be controlled when they are grown by factors like the temperature, time

and composition of the dot. In this work, we describe the use of materials like CdS, CdSe

and PbS to produce quantum dots. These quantum dots have the potential to absorb a very

wide portion of the solar spectrum, from the infrared to the ultraviolet.




308

[ RWE-240 ] Graphene and Solar Cells

Ana Cecilia Flores Ortega ([email protected]) 1 , Agustín Enciso

Muñoz 1 , David Armando Contreras Solorio ([email protected]) 1



The World consumption of energy grows at an annual rate of 2 % and 85 % of the

consumption comes from fossil fuels which are not renewable and they have adverse effects

of global warming. The report Climate Change 2014 of IPCC points out that the global

climate is harmfully changing due to the increase of carbon dioxide and other greenhouse gas

emissions. Then it is essential to increase the use of renewable energies like that produced

by solar cells, which directly transform the energy from the Sun into electricity. For this

purpose, it is required to low the price of electricity produced by cells, increasing the

efficiency and using cheaper materials. Graphene is a relatively new material, increasingly

cheaper and environmentally compatible, with extraordinary properties. In this work, we

describe the several uses of graphene for manufacturing solar cells.




309

[ RWE-244 ] Interface study of ITO/ZnO layer and their

effect on CdS/CdTe solar cells

M Zapata-Torres ([email protected]) 1 , E. Hernandez Roriguez 2 , R. Mis-

Fernandez 2 , v. Rejón 2 , E. Valaguez Velazquez 3 , J.L. Fernandez Muñoz 1 ,

J.L. Peña Chapa 2

1 CICATA-IPN, Unidad Legaria, Legaria 694 C.P. 11500 D.F., México 2 Departamento de Física Aplicada, CINVESTAV-IPN, Unidad Mérida, Km. 6 Antigua

carretera a progreso, C.P. 97310, Mérida, Yucatan, México 3 UPIITA-IPN, Av. IPN 2580, C.P.07340 Mexido D.F.

Thin film CdTe/CdS solar cells are typically on the configuration TCO/CdS/CdTe. The

thickness of the CdS film is related to the number of incident photons that reach the CdTe.

Therefore the decrease of the thickness of CdS increase the number of incident photons in

the CdTe layer. However, as the thickness of CdS layer is decreased, we obtain a formation

of localized CdTe/ transparent conductive oxide (TCO) junction, which lead to excessive

shunting and therefore lower the solar cell efficiency. Using high resistive transparent (HRT)

layer is a feasible method to improve the characteristics of CdTe thin films solar cell.

The HRT layers in CdTe solar cells include SnO2, Al2O3, ZnSnO4; and recently ZnO. The

ZnO has the direct energy gap structure of 3.37 eV, and It can be prepared using low

temperature technology such as RF Sputtering. The ZnO is a promising candidate to be used

as HRT layer in CdTe thin film solar cells. It is widely reported that inclusion of so called

HRT layer between TCO and CdS acts to enhance efficiency, although there is no consensus

on the mechanism by which this occurs.

In the present work we growth ZnO layer on ITO coated glass substrate. We studied the effect

of the annealing on the ITO diffusion on the ZnO layer. The ITO/ZnO layer will be

characterized by XPS, X ray diffraction, UV-Vis spectroscopy. In order to study the effect

of ZnO and CdS thickness, we used the AMPS-1D solar cell simulator.

This work is supported by SEP-CONACYT (project 153245) and SIP-IPN (Project

20150090)




310

[ RWE-257 ] Optical spectroscopy and morphology of CaF2

and CaF2:Tb thin films obtained by electrodeposition

technique

Antonio Mendez-Blas ([email protected]) 2 , Ma. Estela Calixto 2 ,

Elias López-Cruz 2 , Bernabe Mari-Soucase 1

1 IDF-Departament de Física Aplicada, Universitat Politècnica de València, Camí de Vera

s/n, 46022 València, Spain 2 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Postal J-48,

Puebla, Pue. 72570, México

Calcium fluoride (CaF2) and calcium fluoride terbium doped (CaF2:Tb) thin films obtained

by electrodeposition method were studied in this work. According to the results, XRD studies

have shown a structural deformation from cubic to tetragonal unit cell as a function of the

doping concentration. The optical absorption showed the typical range of transparency from

IR to UV. From photoluminescence (PL) results it is possible to identify the f-f electronic

transition of Tb3+. The PL at low temperature allows to establish the quenching concentration

when the PL intensity decreases at the highest doping concentration value. However, the

results also showed that the transition of Tb3+ does not seem to be affected by the mentioned

deformation. So, it is possible to use the CaF2 thin films with a double purpose for solar cell

applications, not only as antireflection coating, but also as a host for lanthanide doping for

down conversion of light. These properties could be very useful for photovoltaic

applications, so that the spectral range of light conversion could be increased to achieve

higher conversion efficiency values.

Acknowledgements: This work was partially supported by VIEP-BUAP and NanoCIS grant

269279.




311

[ RWE-314 ] Effect of Window Layer Optimization on

Electronic Properties of Si:H p-i-n Junction

Hiram Enrique Martinez Mateo ([email protected]) 1 , Andrey Kosarev 1

1 Electronic Department, INAOE, Luis Enrique Erro # 1, Santa Maria Tonantzintla, Puebla

P-i-n structures with plasma deposited Si:H layers are commonly used in commercial devices

including application for photovoltaic (PV) solar cells. They are widely reported in literature

but many questions still exist, and data reported by different authors are controversial.

In this work we report the study of p-i-n junction with Si:H layers deposited by plasma

enhanced chemical vapor deposition (PE CVD) with indium-tin oxide (ITO) and zinc oxide

doped by Al (AZO) layers as frontal transparent conductors (TCO) and modification of p+-

layer. The structures have an area S= 0.154 cm2. The samples were fabricated in cluster tool

system with 3 chambers from “MVSyst. Inc.”. Intrinsic Si:H was deposited from

10%SiH4+90%H2 mixture, p+ doped layer Si1-XCX:H(B) from B2H6+CH4+SiH4+H2 mixture

[X means the carbon content in gas phase according to XCH4+(1-X)SiH4 formula, where X

goes from 0.32 to 0.9] and n+ doped layer from 0.01%PH3+ 9.9%SiH4+ 90.09% H2 mixture.

All gases used are semiconductor purity. Deposition temperature was Td= 160° C. Rf

discharge is excited at frequency f=13.56 MHz and power W= 3W. . Substrates of “Corning

1737” glass coated by AZO (optical transmission T(550nm)= 88% and sheet resistance Rsheet=

100 Ω/sq.) , and ITO (T(550nm)= 88% and Rsheet=20Ω/sq.) were obtained from “Thin Film

Devices Inc.”.

Summary of main observations and results: a) Jsc increases with the carbon content in gas

phase, the maximum value of 12mA/cm2 is achieve at X=0.8. Further increment of carbon in

gas phase increases the parasitic series resistance one order of magnitude and therefore, Jsc

decreases; b) p+-window layer thickness between 8nm and 10 nm offers the lower parasitic

series resistance. For ITO-p-i-n devices, the lowest series resistance is Rs=1.08x102 Ω; c)

spectral response, Rph=100*(EQE3.1eV/EQEmax), for short wavelengths increases from 26%

to 42% after carbon content in gas phase optimization of the p+-window layer. Spectral

response, Rph, for short wavelengths increases up to 74% when thickness of p+-window layer

is optimized in the ITO devices.




312

[ RWE-338 ] Perovskites and Solar Cells

Cristina de Lourdes Rodríguez Corvera ([email protected]) 1 ,

David Armando Contreras Solorio ([email protected]) 1



The reports Climate Change Impacts in the United States (2014), promoted by Obama, and

Climate Change 2014 of IPCC point out that the global climate is changing with ominous

consequences due to a global warming caused by the human activity. This warming is caused

essentially by the use of fossil fuels and the side emission of greenhouse gases, mainly carbon

dioxide. Then, it is necessary to increase the use of other forms of energies like that of

photovoltaic, which transforms the electromagnetic radiation from the Sun directly to

electricity. In order to increase the use of electricity from solar cells, it is essential to make

more affordable their production, using cheaper materials and increasing the efficiency,

which measures how much of the radiation received by the cell from the Sun, is transformed

to electricity. The recent use of perovskites for solar cells is very promising. They are a very

good prospect as materials for manufacturing solar cells because these materials are abundant

and have low cost. Cells made of perovskites have reached an efficiency of 17 % in

laboratory. In this work we make an analysis of different types of perovskites, its applications

in solar cells, how a cell made of perovskites works, and some difficulties these kind of cells

present.




313

[ RWE-438 ] Optimization of aluminum-doped ZnO thin

films for application as TCO in a solar cell.

José Amauri Serrano Lázaro ([email protected]) 1 , Betsabee

Marel Monroy Peláez ([email protected]) 1

1 Instituto de Investigaciones en Materiales, UNAM, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán, D.F., México

TCOs (Transparent Conductive Oxides) are of interest due to the peculiar properties they show: high

transparency and high electrical conductivity. ZnO is a TCO used in technology of semiconductors

for solar cells and optoelectronic applications. Currently, aluminum-doped ZnO thin films are an

important part of thin film solar cells.

In this project, aluminum-doped ZnO thin films were obtained by the use of the ultrasonic spray

pyrolysis technique. The influence of the concentration of aluminum incorporated on the precursor

solution (as a dopant atoms source) was studied. The concentration of aluminum was varied from 1.5

to 6 atomic %. Optical, electronic and growth properties of ZnO thin films were analysed. The main

goal was to obtain thin films with the adequate properties of a TCO (transmittance >80% and

electrical resistivity <10-3 Ω*cm).

Results showed that as the concentration of aluminum is increased, there is a change on the

preferential growth of crystals in the thin films, from a (002) orientation to a (101). Regardless of the

aluminum content, thin films showed high transparency in the visible range (>80%) and they showed

an improvement in their electrical properties such a sheet resistance lower than 200 Ω/ and resistivity

lower than 7x10-2 Ω*cm.

Best samples were obtained at a 4.45 atomic % of aluminum showing a transparency of 85%, sheet

resistance and resistivity of ≈91 Ω/ and 4x10-2 Ω*cm, respectively. This shows that the thin films

deposited by ultrasonic spray pyrolysis technique are adequate for its use as a transparent electrode

in a solar cell.

Key words: TCO, semiconductor, cell, transmittance, resistivity, resistance, electrode, ZnO, oxides.

Acknowledgements: This project was partially funded by PAPIIT-UNAM projects IN108215 and

IN100914, CONACYT, Mexico, under Projects 153948 and 179632, and SENER-CONACYT

Project 151076. Thanks are due to C. González, C. Flores, A. Tejeda and J.E. Romero for technical

support. The authors are grateful to A. Guillen and J. Santoyo from Physics Department, Cinvestav

for EDS measurements.




314

[ RWE-496 ] A comparative study of the optical and electrical

properties of solar cells using a SiOx coating obtained by

HFCVD

Karim Monfil Leyva ([email protected]) 1 , Esteban Ojeda

Durán ([email protected]) 1 , Jesús Carrillo López 1 , José

Alberto Luna López 1 , Roberto Carlos Ambrosio Lázaro 1 , Ana Luz Muñoz

Zurita 2

1 Benemérita Universidad Autónoma de Puebla 2 Universidad Politécnica Metropolitana de Puebla

The research on third generation solar cells has been increased due to the increasing price,

scarcity and toxicity of other elements. Currently, the silicon off-stoichiometric (SiOx) has

showed interesting optical properties for optoelectronic applications and it arises as an

important and cheap alternative to play an important role in the down-conversion energy in

the future. SiOx can be deposited by several techniques like Si-implantation on SiO2,

sputtering, laser ablation and Chemical Vapor Deposition (LPCVD) methods. In particular,

SiOx films can be easily obtained by Hot Filament Chemical Vapor Deposition (HFCVD)

when high purity hydrogen is used as a reactive.

In this work, we report a study of the optical properties of SiOx films obtained by HFCVD

and their application as a top coating on silicon solar cells. Hydrogen flow (HF) was varied

between 25 and 75 sccm to obtain SiOx films. Step measurements were applied to calculate

the thickness of our films. Fourier transform infrared (FTIR) measurements were obtained to

confirm a change on films stoichiometry. Absorbance spectra of SRO films showed rocking

and bending vibration modes similar to stoichiometric silicon dioxide but an asymmetric

stretching mode revealed the non-stoichiometric nature of our semiconductor films. SiOx

films also showed a red band from 500 to 900 nm (depending on the HF) and this emission

was attributed to defects produced by the transport of the precursors. Solar cells with a SiOx

coating were obtained using two different lithography methods for metallic contacts. Current-

voltage measurements were obtained from solar cells to calculate figures of merit. The solar

cells with metallic contacts obtained by Al-etch have higher efficiency than those obtained

by liftoff. The solar cells with highest efficiency also have the SiOx films with the highest

photoluminescence, which it confirms the enhancement on electrical parameters according

to the improvement in the UV range.




315

[ RWE-562 ] Analysis of quality of production of biodiesel

from crude avocado (Persea americana Mill. Hass, Fuerte and

Criollo varieties) oils

Luis Alberto Juárez-Morán 2 , Edith Cortés-Rodríguez 1 , Isabel Hernández-

Castillo 1 , Joel Diaz-Reyes ([email protected]) 1

1 Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional. Ex–

Hacienda de San Juan Molino. Km 1.5 de la Carretera Estatal Santa Inés Tecuexcomac-

Tepetitla. Tepetitla, Tlaxcala. 90700. México 2 Facultad de Ciencias Fisicomatématicas, Benemérita Universidad Autónoma de Puebla.

Av. San Claudio y 18 Sur. Col. San Manuel, Ciudad Universitaria. Puebla, Puebla. 72570.

México.

The process of transesterification, also called alcoholysis, is the method most commonly used

for the production of biodiesel. Crude oil avocado variety Fuerte was extracted by

centrifugation. To the crude avocado oil transesterification was reacted with methanol and

two conventional catalyst (KOH and NaOH) for 1 hour at a temperature of 60°C. Room

temperature Raman Spectroscopy was used to monitor the process of transesterification. The

oil Raman spectrum shows four dominant peaks at 3010, 2926, 2889 and 2856 cm-1

attributed to the symmetric stretch =C-H, to the asymmetric bond C-H, to symmetric –CH3

and symmetrical bond –CH2. In particular, two bands were observed in avocado oil located

in 1750 and 878 cm-1 attributed to C=O bond and C-C, respectively, while in the Raman

spectra after transesterification process the first band shift to 1742 cm-1 and the second

disappears, which confirms the formation of biodiesel.




316

SEMICONDUCTORS (SEM)

Chairmans:

Sergio Jimenez (CINVESTAV-Qro) Salvador Gallardo Hernández (CINVESTAV-DF)

Sesión Oral

[ SEM-14 ] Nonlinear current-voltage characteristics of a

semiconductor barrierless structure

Andrey Meriuts 2 , Yuri Gurevich ([email protected]) 1

1 Departamento de Fisica, CINVESTAV-I.P.N., 2508, Apartado Postal 14-740, Mexico D.F.

07000, Mexico 2 Department of Materials for Electronic and Solar Cells, National Technical University

‘Kharkov Polytechnic Institute’, 21 Frunze St., Kharkov 61002, Ukraine

A nonlinear model for the electric current in a metal-intrinsic semiconductor-metal structure

without potential barriers in contacts is considered using a drift diffusion approach. An

analytical solution of the continuity equations and the current-voltage characteristic for

various recombination rates in the contacts are obtained. It is shown that the current-voltage

characteristics of such a structure exhibit not only linear behavior, corresponding to Ohm’s

law, but may also possess properties of current-voltage characteristics of the rectifier diode.

It is also possible current-voltage characteristics with saturation in both forward and

backward directions. Physical model that explains the obtained results is proposed




317

[ SEM-15 ] Thermoelectric cooling in bipolar

semiconductor structures

Enrique Velázquez-Pérez 1 , Oleg Titov 3 , Yuri Gurevich


1 Departamento F1ısica Aplicada, Universidad de Salamanca, Plaza de la Merced, E-

37008 Salamanca, Spain 2 Departamento de Fisica, CINVESTAV-I.P.N., 2508, Apartado Postal 14-740, Mexico D.F.

07000, Mexico 3 Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas 152, C.P. 07730 México,

D.F., México

This presentation is devoted to the analysis of thermoelectric cooling phenomena in

semiconductors containing potential barriers (p-n-junction). The formulation of an adequate

self-consistent

theoretical model describing the effect is presented. The role of the recombination rate in

lineal approximation of the electric current leads to a new formulation of the set of equations

describing the Peltier effect that is discussed in detail. The importance of re-distribution of

non-equilibrium charge carriers, which has been ignored in most of the publications on this

subject, is also shown.

Moreover, it is proved that the conventional theory of thermoelectric cooling, which does not

take into account the influence of non-equilibrium charge carriers, is not correct in general.

In the present work, it is demonstrated that the Peltier effect strongly depends on the

recombination rate. In particular, it is shown that the sign of the Peltier effect changes with

the value of the recombination rate.




318

[ SEM-16 ] Electrical resistance of a bipolar

semiconductor in a linear Ohm law

Igor Lashkevych ([email protected]) 2 , Yuri G. Gurevich 1

1 Departamento de Física, CINVESTAV-IPN, Apdo., Postal 14-740, 07000 México, DF,

México 2 Instituto Politécnico Nacional, UPIITA, Av. IPN, No. 2580, col. La Laguna Ticomán, del.

Gustavo A. Madero, México, D.F., C.P. 07340, México

The linear electrical resistance of a nondegenerate bipolar semiconductor, which contacts

with the metal from both sides, is investigated in general case, i.e., when the presence of both

nonequilibrium charge carriers (electrons and holes) and nonequilibrium temperature are

taken into account. It is necessary to emphasize that the concentration and energy

nonequilbriums arise automatically, when the electrical current flows even in a linear

approximation with respect to perturbation. The expression for the electrical resistance is

obtained. This expression depends on electrical conductivities of electrons and holes, the

thermal conductivity, the bandgap, the lifetime of charge carriers, the surface recombination

rate on the contacts of a semiconductor with a metal. The explanation of this is as follows.

When the electrical current flows in a semiconductor, then recombination arises due to the

nonequilibrium electrons turn up in a semiconductor near its contacts with a metal [1]. Also,

nonradiative recombination causes the heat dissipation [2], in turn provoking of the

temperature changes. Therefore, not only nonequilibrium charge carriers, but also

nonequilibrium temperature arises in a semiconductor. The nonequilibrium temperature will

produce thermo-generation of electron-hole pairs in a semiconductor [3,4], i.e., will change

the distribution of nonequilibrium charge carriers (electrons and holes). Also, it will generate

thermal electrical currents, in turn changing the value of the electrical conductivity.

It is shown that the electrical resistance is equal to the classic result, (l is the

semiconductor length, S is the cross-sectional area, ( ) is the electrical conductivity of

electrons (holes)), only, if the surface recombination rate on the contacts is sufficiently strong

or the lifetime of charge carriers is sufficiently small. The partial cases are considered: the

semiconductor with small and large thermal conductivities; the monopolar electron and

monopolar hole semiconductors; the strong and weak surface recombination rates; the small

and large lifetimes of charge carriers. The concrete expressions for the effective electrical

conductivity are obtained in all partial cases.

[1]. Yu.G. Gurevich, G.N. Logvinov, G. Espejo, O.Yu. Titov, and A. Meriuts, “The role of

nonequilibrium carriers in linear charge transport,” Semiconductors 34, 755–758 (2000).




319

[2]. Yu.G. Gurevich and I. Lashkevych, “Sources of fluxes of energy, heat, and diffusion heat in a bipolar

semiconductor: Influence of nonequilibrium charge carriers,” Int. J. Thermophys. 34, 341–349 (2013).

[3]. G. Espejo-Lopez, O.I. Lyubimov, O.Yu. Titov, and Yu.G. Gurevich, “Corriente eléctrica de portadores

calientes en semiconductores intrínsecos: desequilibrio en concetración,” Revista Mexicana de Física 50, 620–

624 (2004).

[4]. I.N. Volovichev, G.N. Logvinov, O.Yu. Titov, and Yu.G. Gurevich, “Recombination and lifetimes of

charge carriers in semiconductors,” J. Appl. Phys. 95, 4494–4496 (2004).

INVITED TALK

[ SEM-18 ] DEVELOPING AN ELECTRONIC DEVICE

IN THE EUROPEAN UNION: n-GaInP/p-

GaAs(C)/GaAs(Si)/GaAs HBT

Jaime Mimila-Arroyo ([email protected]) 1

1 Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Dpto.

de Ing. Eléctrica-SEES, Av. Instituto Politécnico Nacional No 2508, México D.F. CP

07360, México

The heterojunction bipolar transistor (HBT) n-GaInP/p-GaAs(C)/n-GaAs(Si)/GaAs handles

current densities as high as ~120 KA/cm² at high frequencies. However, its current gain might

be unstable, presenting the so called “burn-in” effect, making circuit design quite

complicated. This behavior, since discovered, was related to the presence of residual

hydrogen in the HBT base region although with no prove nor proposals of the physical

processes that should produce it.

This HBT is manufactured and commercialized by several companies with strong differences

on current gain and instability, making some of them loose their share of the market. To

improve the device performance to the state of the art the European Union supported a

research project involving several industrial partners and university labs. The considered

approach included all the technological steps since the epitaxial growth and material

characterization of the HBT structure, the associated device technology, high frequency

characterization until the assessment of the device performance as part of telecommunication

subsystems as Voltage Controlled Oscillators (VCOs) and Low Noise Amplifiers (LNAs)

tested in the outer space.

In this work it will be presented the general research approach and in some detail the studies

that yielded as main results: current gain increase and stabilization. This device now is used

in a wide range of applications mainly in telecommunications as cell phones, wide band

amplifiers, VCOs, LNAs and power amplifiers.




320

[ SEM-19 ] FREE ELECTRON GAS PRIMARY

THERMOMETER: THE BIPOLAR JUNCTION

TRANSISTOR

Jaime Mimila-Arroyo 1



07360, México

Since the discovery of the junction diode and the bipolar junction transistor (BJT) their ability

to sense temperature was clearly established, becoming the most practical semiconductor

based thermometric elements, although with low accuracy, even when calibrated. This

property stems from the temperature dependence of their charge transport properties as them

depend on their free carrier concentration, mobility and diffusivity, which are temperature

dependent as well, but mainly from the free carrier energy distribution. Indeed, in

semiconducting materials the energy distribution of the free carriers, is given by the Fermi-

Dirac statistics which, for energy levels several kT above the Fermi level (k is Boltzmann´s

constant and T the temperature), determines that their occupation probability has an

exponential dependence on the energy level and the free carriers gas temperature. As a

consequence, in a forward biased PN junction the concentration of free carriers at each side

of the junction able to overcome the built-in junction energy barrier, and thus the junction

current, depends exponentially on the barrier height, modulated by the bias, and on the carrier

gases energy distribution i.e., the gas temperature. Since the proposition of Verster who

showed that for the case of the BJT using two collector currents; IC1(VEB1) and IC2(VEB2), and

their corresponding emitter-base voltages; VEB1 and VEB2, its temperature could be obtained

directly this device has been widely used as an inexpensive thermometer.

In this presentation, the physics behind the thermometric properties of the BJT will be widely

discussed and it will be demonstrated that under particular bias conditions the collector

current of a bipolar junction transistor, indeed, constitutes a probe of the energy distribution

of the transistor free charge carrier gases from whose behavior its temperature can be

extracted through a rigorous mathematical method. It will be also shown that the extracted

temperature is independent of every transistor physical parameters and geometry

constituting, thus, a primary thermometer. Finally it will be shown that using commercial

silicon transistors at several fix temperature points, the method here described, extracts the

temperature with an error of a few milli-Kelvin. This primary thermometer being the smallest

and simplest actually available.




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[ SEM-67 ] Calculation of Liquid-Solid Coherent Phase

Diagram for InAs-InP System to grow Low-Dimension

Structures

Ulises Zavala Moran ([email protected]) 1 , Andrei Yu. Gorbatchev 1 ,

Viatcheslav A. Michournyi 1 , Franscisco De Anda 1

1 Instituto de Investigacion en Comunicacion Optica - Universidad Autonoma de San Luis

Potosi, Av Karakorum 1470, Lomas 4a. Secc, 78210 San Luis, S.L.P.

Previous studies showed that low-dimensional structures can be grown by Liquid Phase

Epitaxy (LPE). Particularly, we have reported about experiments in the InAs-InP [1] system

and mentioned that the epitaxial structures grown on InP substrates from pure (In-As) liquid

phases contain a certain amount of P.

The aim of this project is to present a model to describe the complex process that occurs in

the liquid-solid interface (l-s). For this purpose we have calculated a coherent phase diagram

of the InAsP liquid phase which is in equilibrium with the epitaxial layers grown on the InP

substrate, considering the elastic energy generated by the lattice mismatch between the

epitaxial layer and the substrate. The Gibbs energies of the liquid and solid phases were

obtained using the CALPHAD [2] method with optimized thermodynamic parameters [3-5].

The elastic energy causes the lattice-latching effect and lowers the liquidus point so that the

liquid phase at the interface with the solid is actually overheated when a mismatched layer is

growing. According to calculations, in the system In-As-P(l)-InP(s) , for liquid phases with

a liquidus temperature of 400 ° C, the maximum overheating reaches 26 ° C. These results

suggest that at the InAs(l)-InP(s) interface the growth process is the result of two

simultaneous competing processes: dissolution and crystallization.

[1] U. Zavala Morán, A. Yu. Gorbatchev, V. A. Michournyi, Analysis of epitaxial layers

grown by Liquid Phase Epitaxy in contact of InAs liquid phase with InP substrate. LiSci 2015

Summer School.

[2] H.L. Lukas, J. Weiss and E. Th. Henig, Strategies for the calculation of Phase Diagrams,

CALPHAD 6(3), 229-251, 1982

[3] Jain-Yun Shen, Christian Chatillon, Ibrahim Ansara, Andy Watson, Bridget Rugg, Tim

Chart, Optimization of theThermodynamic and Phase Diagram Data in the Ternary As-Ga-

In Sysem, CALPHAD 19(2), 215-226, 1995

[4] Ch. Li, J.-B. Li, and W. Zhang, A Thermodynamic Assessment of the Ga-In-P System,

Journal of Phase Equilibria 21(4), 357-363, 2000

[5] K. Ishida, H. Tokunaga, H. Ohtani and T. Nishizawa, Data Base for Calculating Phase

Diagrams of III-V Alloy Semiconductors, J. of Crystal Growth 98, 140-147, 1989




322

[ SEM-109 ] 2-D numerical simulation of a tft with

chemically deposited Poly-CdS active layer

Laura Adriana Berrout Ramos ([email protected]) 1 , Abimael

Jiménez Pérez 1 , Amanda Carrillo-Castillo 1

1 Electrical and Computer Department, Universidad Autónoma de Ciudad Juárez, Ciudad

Juárez, Chihuahua 32310, México

A two-dimensional numerical simulation is performed using physically based device

simulator Atlas/Silvaco to analyze the device behavior of a n-type thin film transistor (TFT)

with CdS semiconductor thin film, prepared by a low temperature chemical bath deposition

(CBD) method. The CdS films were deposited by immersion of the substrates in a CBD

solution prepared from cadmium nitrate (Cd(NO3)2), sodium borohydride

(NaBH4)/hydrazine (N2H4), pH 10 ammonia buffer and thiourea (Sc(NH2)2). The total

reaction volume was adjusted with water to 62 ml. The temperature of the solution was

maintained at 70 oC +/- 1 oC for 12 minutes. Meanwhile, the numerical simulation was based

on fabricated long channel TFTs. The total Density of Defect States (DDS) distribution of

trapping states g(Et) in the polycrystalline CdS films is considered and it is composed of four

bands: two tail bands (a donor-like valence band, gTD(Et) and an acceptor-like conduction

band, gTA(Et)), and two deep Gaussian level bands (one acceptor-like, gGA(Et) and the other

donor-like, gGD(Et)) by

The knowledge of the DDS is helpful for the performance study and optimization of n-type

TFT with CdS. First, the CdS film was considered as a homogenous material with an effective

density of trapping states to avoid complex mesh definitions of multigrain structures. Then,

the DDS behavior was predicted by the Fermi-Dirac occupation function. Finally, the capture

and emission processes are predicted by Atlas using the Schockley-Read-Hall (SRH)

recombination model. As a result of this study, the electrical characteristics of Cds TFTs

were predicted using the embedded density of defects model and the principal parameters,

such as threshold voltage, mobility and electric field were analyzed. The electrical

performance and optimization of these devices could be related to both acceptor and donor-

like states (density of vacancies or defects) in the active layer deposited by CBD.




323

[ SEM-111 ] Lattice dynamics studies of NbTe2 crystals

Aarón Hernán Barajas Aguilar 1 , Francisco Rodríguez Melgarejo 1 , Martín

A. Hernández Landaverde 1 , Gabriel López-Calzada 1 , Chuck Irwin 2 ,

Sergio J. Jiménez Sandoval ([email protected]) 1

1 Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro 2 Department of Physics, Simon Fraser University

Transition Metal Dichalcogenides (TMD) are materials with layered structures which consist

of stacks of chalcogenide-transition metal-chalcogenide unit layers bind together by weak

van-der-Waals-type forces. These characteristics have made possible to get two-dimensional

materials with ease by obtaining single molecular layers, which has triggered intensive

research efforts from both theoretical and experimental points of view because of the inherent

remarkable 2D phenomena that occur in them and because of their potential applicability.

NbTe2 is as TMD with metallic-like properties (in-plane resistivity ~10-4 ohm-cm). The

NbTe2 crystals were grown by the vapor transport method by heating the elements in an

evacuated quartz ampoule. Raman scattering experiments were performed at room

temperature on fresh surfaces right after exfoliating NbTe2 crystals. We report here the

Raman spectra of NbTe2 crystals obtained by exciting the samples with the 785, 632.8, 514.5,

488 and 457 nm laser lines. Preliminary theoretical results of the calculated vibrational modes

using density functional theory are also provided.

[ SEM-149 ] New method to extract the emitter series

resistance of a bipolar junction transistor

JAIME MIMILA-ARROYO ([email protected]) 1



07360, México.

Parasitic series resistances in electronic devices are ubiquitous, unavoidable and highly

deleterious. Their presence seriously degrades devices performance mainly limiting the

handling of power, decreasing the operating frequency and increasing electrical noise.

Measuring the series resistance is a complex task as it depends on the current being handled

as well as from the temperature at which the device is operating.

Here we present a new method to extract the parasitic series resistance of the emitter of a

bipolar junction transistor relying on a particular application of the model of Schockley for




324

the transistor charge transport properties and experimental measurement of the collector

current under a particular bias condition. From these data the precise transistor temperature

can obtained as well as the collector saturation current at that temperature which are used to

straightforwardly obtain the emitter parasitic series resistance at any device temperature and

handling any current. The method has been applied on several out of the shelf transistors.

[ SEM-153 ] Current-voltage-temperature characteristics

of flexible Schottky barrier diodes based on

ZnO/PEDOT:PSS.

Norberto Hernandez-Como ([email protected]) 2 , Francisco

Hernandez-Cuevas 2 , Rodolfo Garcia-Lozano 1 , Victor Jiménez-Hernandez

1 , Andres Rodriguez Lopez 1 , Israel Mejia 3 , Miguel Aleman 2

1 Centro Universitario Ecatepec, Universidad Autónoma del Estado de México, Ecatepec,

México. 2 Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional,

México 3 Department of Materials Science and Engineering, University of Texas at Dallas, USA.

In this work, Schottky barrier diodes (SBDs) based on ZnO/PEDOT:PSS thin films have

been fabricated. The fabrication process was first done on glass substrates and then

transferred to PET substrates. The SBDs current-voltage characteristics were evaluated under

different temperatures for the extraction of the effective barrier height (ΦB) and the

Richardson constant (A*). These are fundamental parameters that characterize the thermionic

emission process in SBDs. The obtained ΦB turned out to be 0.96 eV and the A* was 0.18 A

cm-2 K-2, which was significantly lower than the theoretically expected value of 32 A cm-2

K-2 for n-type ZnO. The difference in A* is related to the formation of a non-ideal Schottky

contact between the organic PEDOT:PSS and the ZnO. The study and understanding of the

SBDs is important because these types of devices can be used in applications such as:

ultraviolet photodiodes, half-wave and full-wave rectifiers, temperature sensors, etc. The

usage of PET substrates allows the application of the fabricated SBDs in flexible electronics.




325

[ SEM-182 ] Local Atomic Structure of Co Doped ZnS

Juan Argel Hoy Benítez ([email protected]) 2 , Francisco Javier

Espinosa Faller ([email protected]) 3 , José Mustre de León 2 ,

Juan Lezama Pacheco 1

1 Earth Sciences, Stanford University, 450 Serra Mall, 94306 Stanford, California, Estados

Unidos 2 Física Aplicada, CINVESTAV-Mérida, Antigua carretera a Progreso Km 6, Cordemex,

97310 Mérida, Yucatán, México 3 Unidad Experimental Marista, Universidad Marista de Mérida, Periférico Norte Tablaje

Catastral 13941, 97300 Mérida, Yucatán, México

The local atomic structure of Cobalt doped Zinc sulfide was studied through Extended X-ray

Absorption Fine Structure Spectroscopy (EXAFS). Heavily Co doped ZnS thin film samples

were grown over soda lime glass substrate by radio frequency magnetron sputtering at a

substrate temperature of 150 °C. Thin film characterization includes X-ray Diffraction,

Energy Dispersive X-ray Spectroscopy, and Scanning Electron Microscopy. Results from

EXAFS relative to nearest neighbour environment around impurities including distance to

nearest neighbors and Debye-Waller factors are reported.

INVITED TALK

[ SEM-216 ] Hybrid Device Structures based on

Combination of Organic-Inorganic Semiconductors

Andrey Kosarev ([email protected]) 1 , Svetlana Mansurova 2 , Ismael

Cosme 2

1 Electronica, Insituto Nacional de Astrofisica, Optica y Electronica 2 Optica, Insituto Nacional de Astrofisica, Optica y Electronica

Last years a strong trend on incorporation of non-crystalline materials in electronics paved

the ways for new classes of large area and flexible devices. Among them photovoltaic (PV)

solar cells and displays are of principal importance. Discovery in 80-ies possibility of doping

of amorphous silicon (a-Si:H) deposited by plasma enhanced chemical vapor deposition (PE

CVD) resulted in new products such as flat displays (LC AMD liquid crystal active matrix

display) and large area (with one or both dimensions more than 1 m) thin film solar cells

produced by revolutionary roll-to-roll technology on flexible substrates (metal, plastic).




326

Recent results of research and development (R&D) in organic semiconductors (OSC) and

their applications for displays and PV solar cells are very impressive and promising e.g. for

flat panel displays (OSC displays show better contrast, more brilliant colors vs LC AMD)

and for thin film PV solar cells (8% efficiency was demonstrated in laboratory). PE CVD

process for deposition inorganic semiconductors (ISC) and multilayered device structures is

low temperature technology (Tdeposition < 200 C) and fully compatible with both standard

crystalline silicon technology and OS technology. Both PECVD deposition and OS

fabrication can be easily scale-up for industrial fabrication. It should be noted that PECVD

semiconductors and OS demonstrate complementary optoelectronic properties. Therefore

study of hybrid device structures comprising ISC PECVD materials and OS is of much

interest and promise.

In this talk we present some overview of principal physical ideas for description of electronic

properties for both ISC and OSC materials, fabrication of ISC and OSC materials, effect of

deposition conditions on opto-electronic properties, some hybrid device structures and their

characteristics in comparison with those reported in literature. For illustrations we shall use

data and results obtained in INAOE.

[ SEM-252 ] Studiy of a new perovskite as the anode for

SOFCs

José Juan Alvarado Flores ([email protected]) 1 , Jaime Espino

Valencia 1 , Jaime Espino Valencia1

1 Universidad Michoacana de San Nicolás de Hidalgo

New types of La0.8Sr0.2Cr0.5Mn0.5O3-δ (LSCM) perovskite composites with the addition of Cu

in solid solution, XCu (X = 25, 35 and 45%), were synthesized via the sol-gel method as

alternative anodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) and

characterized by several techniques. Phase formation of the LSCM-Cu cermets was

confirmed by X-ray diffraction (XRD). Electrical conductivity was obtained from room

temperature to 800 °C, indicating the presence of two types of behaviors: semiconductor and

metal. When the concentration of Cu was 25 and 35%, the dominant behavior was the

semiconductor type. The thermal expansion coefficient (TEC) determined was linearly

inversely proportional to the concentration of Cu. The results of electrical conductivity, TEC,

and morphological analysis suggested that the anodes with 25 and 35% Cu are most suitable

for use in the IT-SOFCs.




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[ SEM-321 ] Synthesis and tribological study of

graphene modified with MoS2 as additive in lubricating

oils.

Jorge Alberto Brandy Garza ([email protected]) 1 , Fabio Chalé

Lara 1 , José Dolores Óscar Barceinas Sánchez 2 , Felipe Caballero Briones


1 Instituto Politécnico Nacional, Laboratorio de Materiales Fotovoltaicos, CICATA

Altamira, Km 14.5 Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira,

México. 2 Instituto Politécnico Nacional, Laboratorio de Tribología, CICATA Querétaro, Cerro

Blanco No. 141. Col. Colinas del Cimatario, 76090 Santiago de Querétaro, México.

The friction and attrition are the main causes of low efficiency in the machines which

constitute approximately 30% energy loss consumed globally. To lessen these effects were

been used different types of oil-based lubricants with additives that included molybdenum

disulfide (MoS2) and graphite, which improve the lubricating properties of the oils.

In this research, graphene oxide (GO) was synthesized with different oxidation degrees using

the modified method Hummers. The GO was chemically decorated with molybdenum

disulfide using sodium molybdate and thiourea as precursors of molybdenum (Mo) and sulfur

(S), respectively. The GO powders prepared were tried using a reducing sugar to compare

the structure and the tribological properties of GO, reduced GO and MoS2-GO.For recognize

the crystalline structure were realized X-ray diffraction analysis, where was found a signal

between 10 and 11° related to the plane (002) of the laminar structure of GO. For studying

the molecular structure was used infrared spectroscopy for Fourier transform, where was

observed the oxygenated groups that been presented in the GO sheet, also the microstructure

was determined by Raman spectroscopy. To study the effect of these materials as additives

of lubricating oils, dispersions of them were prepared in a oil-based lubricating and were

characterized in a ball on disk tribometer, where the friction coefficient is reduced using the

GO/MoS2 as additive compared to the other powders used. The attrition surfaces of the discs

used in the tribological tests were studied by scanning electron microscopy for determining

the lubricating ability of each formulation over the oils.

Projects financed by SIP20140293 and SIP 20144607.




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[ SEM-331 ] Nanoelectrical characterization of ZnO:Al

films prepared by spray pyrolysis

Javier Armando Baron Miranda ([email protected]) 2 , Jordi

Díaz Marcos 3 , Ismael Diez Pérez 1 , Fausto Sanz Carrasco 1 , Samuel San

Juan Hernandez 2 , Francisco Javier Espinosa Faller 4 , Fabio Felipe Chale

Lara 2 , Felipe Caballero Briones ([email protected]) 2

1 Departamento de Química-Física, Universidad de Barcelona, Diagonal 645, y el Instituto

de Bioingeniería de Cataluña, Baldiri Reixac, 15-21, 08028, Barcelona, España 2 Instituto Politécnico Nacional, Laboratorio de Materiales Fotovoltaicos, CICATA

Altamira, Km 14.5 Carretera Tampico Puerto Industrial Altamira, 89600 Altamira, México 3 Unidad de Técnicas Nanométricas, Centros Científicos y Tecnológicos Nanodivulga UB,

Universitat de Barcelona, Lluís Solé i Sabarís, 08028 Barcelona, España 4 Universidad Marista de Mérida, Periférico Norte Tablaje Catastral, 13941, 97300

Mérida México.

In this work, zinc oxide films with different amounts of aluminum in the precursor solution

(0, 0.5, 1, 2, 5 and 10 % [Al/Zn]) were prepared by ultrasonic spray pyrolysis onto glass

substrates using zinc acetate as zinc precursor and 450 oC of substrate temperature. The films

were characterized by X-ray diffraction, optical transmittance, scanning electron microscopy

and current sensing atomic force microscopy. X-ray diffraction indicates a mixture between

pure ZnO and some (Zn,Al)O phase with no evidence of crystalline Al2O3. The transmittance

maximum and band gap increases with the [Al/Zn ratio. The morphology was studied by

SEM evolves from hexagonal flakes to hexagonal micro columns that first appear included

between the flakes and thereafter dominate in the images. AFM indicate a grain size reduction

from ZnO to ZnOAl up to 1% [Al/Zn] in the precursor solution as well as an increment in

the conductivity, followed by a grain size increase as a reduction in the conductivity. CAFM

indicates that conduction changes from grain bulk conduction to conduction through the grain

boundaries when [Al/Zn] increases from 0.5-1% to 2-10%. Undoped ZnO shows uneven

conduction paths, possibly related with the uneven distribution of vacancies.

Financed by SIP20151074 and SIP2015599




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INVITED TALK

[ SEM-370 ] Radiation Effects on Advanced SOI

MOSFETS

José Joaquín Alvarado Pulido ([email protected]) 1 ,

Valeriya Kilchytzka 2 , Blanca Susana Soto Cruz 1 , Antonio Cerdeira

Altuzarra 3 , Denis Flandre 2

1 Centro de Investigación en Dispositivos Semiconductores, Instituto de Ciencias,

Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Edificio 103-C, Blvd.

14 Sur y Av. San Claudio, Fracc. Jardines de San Manuel. C.P. 72450, Puebla, México. 2 ICTEAM Institute, Université catholique de Louvain, B-1348, Louvain-la-Neuve, Belgium

3 Sección de Electrónica del Estado Sólido, CINVESTAV-IPN, D.F. México

This work reviews our previous works on the degradations caused by high-energy neutrons

and gamma-rays in advanced MOSFETs. Firstly, we showed that the degradation caused by

high-energy neutrons in planar fully depleted (FD) and multiple-gate (MuG) SOI MOSFETs

are largely similar to that caused by gamma-rays with similar doses. Secondly, a comparative

investigation of high-energy neutrons effects on strained and non-strained devices revealed

a clear difference in their response to high- energy neutrons exposure. Finally, based on

simulations and modeling of partially-depleted (PD) SOI digital circuits, we demonstrated

how radiation-induced oxide charge and interface states build-up can affect well-know

tolerance of SOI devices to transient effects.




330

[ SEM-381 ] MoS2 thin films deposited by chemical bath

deposition on Si and glass substrates.*

D.E. Perez-Barragan 2 , A.R. García-Sotelo 1 , E. Campos 1 , O. Zelaya-

Ángel 1 , M. Melendez-Lira ([email protected]) 1

1 Departamento de Física, CINVESTAV-IPN, , Apdo. Postal 14-740, México, DF 07000,

México 2 ESIQIE-IPN Escuela Superior de Ingeniería Química e Industrias Extractivas del

Instituto Politécnico Nacional, U.P. Adolfo López Mateos, Col. San Pedro Zacatenco, C.P.

07730 México DF, México

Even when the increasing interest in MoS2 is driven by their properties as a 2D material, the

deposit of MoS2 films using low cost techniques is interesting and allows to explore the

feasibility to find routes to produce low cost materials capable to improve photovoltaic

structures, etc. The results of the deposit by chemical bath deposition of MoS2 films

employing Si and glass substrates are presented. Two precursor were employed:

Ammonium molybdate (NH4)2MoO4 and Ammonium molybdate tetrahydrate

(NH4)6Mo7O24 · 4H2O. It was found that the first precursor is adequate to obtain amorphous

MoS2 films on glass while the second allows to obtain films on silicon.

The samples crystallized after a thermal annealing process carried out at 300 °C. UV-Vis

spectroscopy indicated a shift in the absorption edge from the MoS2 bulk value, probably

related to the film thickness. Samples were characterized also by XPS, Raman and AFM.

The results are discussed in terms of the structural characteristic of the films and the

interaction with the substrate.





331

Sesión Poster

[ SEM-13 ] The influence of the recombination on the

energy flux density in semiconductor structures

José Luis Salazar Laureles ([email protected]) 2 , Yuri G. Gurevich


1 Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, 07000, Distrito

Federal, México. 2 Universidad Autónoma Metropolitana Unidad Lerma, Av. Hidalgo Poniente 46, Col. La

Estación, Lerma de Villada, Municipio de Lerma, Estado de México, C.P. 52006

A theoretical study of the influence of the recombination to determine the energy flux density

is presented. It was studied a linear approximation when there are different temperatures at

the ends of one-dimensional semiconductor structures. The mathematical expressions for the

energy flux density in the cases of weak and strong recombination are presented.

keywords: Recombination, energy flux, semiconductors.

[ SEM-49 ] Effect of thermal annealing on points defects

in Al-N co-doped ZnO films studied by Raman

spectroscopy

Luis Zamora-Peredo ([email protected]) 1 , Antonio Martínez-Juan 1 ,

Julián Hernández-torres 1 , Leandro García-González 1

1 Centro de Investigación en Micro y Nanotecnología, Universidad Veracruzana, Adolfo

Ruiz Cortines 455, C.P. 91000, Veracruz, México

In this paper, we present the influence of annealing temperature on the structural properties

of Al:N co-doped ZnO films by Raman microscopy. The films were deposited by sputtering

technique on silicon substrates, Al-concentration was kept constant and the nitrogen flow

was changed to 6, 12 and 15 sccm. An annealing process was performed by baking the sample

for 30 minutes at temperatures of 300, 400, 500, 600 and 700 °C. In samples without

annealing, Raman spectra show two vibration modes one located at 581 cm-1 associated with




332

the E1 mode of ZnO and another at 275 cm-1 which has been related to the incorporation

nitrogen and the presence of point defects like Zni. Raman intensities of both modes, I275 and

I581, decreases when the nitrogen flow increases from 6 to 12 and 15 sccm. After annealing,

in the Raman spectra it was observed that I275 increases with temperature, reaches a maximum

around 500 ° C and decreases at higher temperatures. X-ray diffraction measurements after

annealing show that the tensile stresses have decreased and thus the crystalline quality has

improved.

[ SEM-61 ] electronic transmission in a finite superlattice

of magnetoelectrostatic barriers on graphene with a

Pascal profile in the barriers-width

Raúl Alberto Reyes Villagrana ([email protected]) 1 , Jaime

Raúl Suárez López 1 , Isaac Rodríguez Vargas 1 , Jesús Madrigal Melchor ([email protected]) 1

1 Unidad Académica de Física, Universidad Autónoma de Zacatecas, Carretera

Solidaridad con esquina paseo la Bufa S/N, C.P. 98060, Zacatecas, Zacatecas, México.

Exist a broad field of research on fractals in different areas such as biology, chemistry,

physics, etc. And, it is in this last where they have been deepened in the study of electronic

properties of devices using quasi-regulars systems like Cantor, Fibonacci, Period-doubling

and more. This paper presents a study on the transport properties of Dirac electrons through

a finite superlattice of magneto-electrostatic barriers on a sheet of graphene. We calculate the

electronic transmission probability using the transfer matrix method and the formalism of

linear Landauer-Büttiker in a finite superlattice where width of the barriers is modulated by

a numerical sequence taken from Pascal’s triangle. This sequence is formed the quantity of

odd number in each of the triangle rows and has the pattern 1-2-2-4-2-4-4-8-… The sequence

has the property of self-similarity. The transmission spectrum is intermediate between that

produced by a periodic superlattice and that produced by a disordered one. The transmission

spectra are very sensitive to the different parameters in the structure, such as, ratio barrier-

width (Pascal´s profile), incidence angle, height of electrostatic barrier and magnetostatic

field. The conductance spectra show a very interesting structure, and shown oscillations in

different energy intervals below and up to the electrostatic barrier height. This oscillations

can be explained by the opening and closure subband in the bounding state. By other hand,

all subbands are degenerate.




333

[ SEM-62 ] Conductance and electronic tranmission in a

thyristor based-graphene

Raúl Alberto Reyes Villagrana ([email protected]) 1 , Jaime

Raúl Suárez López 1 , Isaac Rodríguez Vargas 1 , Jesús Madrigal Melchor


1 Unidad Académica de Física, Universidad Autónoma de Zacatecas, Carretera

Solidaridad con esquina paseo la Bufa S/N, C.P. 98060, Zacatecas, Zacatecas, México.

The thyristor is a device with a structure of four layers, PNPN, similar to a junction between

two transistors, PNP-NPN. This device has different applications, but its main function is to

control high power systems. This paper presents a study on the transport properties of Dirac

electrons through a structure of four magneto-electrostatic barriers on a sheet of graphene, is

presented a based-graphene thyristor. The pnpn structure was calculated using the transfer

matrix method and the formalism of linear Landauer-Büttiker. We performed a study of four

cases. The positive polarization voltage and the magnetic fields were kept constant. The

results show that at normal incidence, appears three transmission bands well-defined, with

increasing the negative polarization voltage, increases the width of the transmission bands.

For oblique incidence, the transmission bands has a toward blue shift and these become

narrow. The value of the control voltage (Vn) opens the transmission windows as a function

of the deepness of wells. The contour plots have a very interesting structure when the control

voltage for the well is more negative. The conductance shows oscillations and peaks in the

structure. The conductance oscillations can be explained by the opening and closure of

subbands of bounding states. The bond states show degeneration and have three subbands,

and goes down with the diminishing of the value of voltage control. Exist interest from the

authors to explore further the benefits presented graphene in the development of new devices.




334

[ SEM-65 ] Effect of a CdS interlayer in

thermochromism and photochromism of MoO3 thin

films

Marcelino Becerril ([email protected]) 2 , Héctor Silva

([email protected]) 2 , Orlando Zelaya 2 , Rafael Ramírez 1

1 Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro, 2 Departamento de Física, Centro de Investigación y de Estudios Avanzados del IPN,

Thin films of molybdenum trioxide (MoO3) and the double layer CdS/MoO3 systems were

deposited by sequential r.f sputtering of cadmium sulfide (CdS) and MoO3 films on well-

cleaned Corning glass substrates. The targets were made from powder of CdS and MoO3.

The glass/MoO3 and glass/CdS/MoO3 films were illuminated with light from a 100 W

tungsten lamp at times of 45-180 min in order to study the photochromic sensitivity of the

films. The films were also thermal annealed at temperatures ranging from 100 to 225 °C to

study the thermochromic properties. The X-ray diffraction studies show that the CdS films

were polycrystalline and the oxide films were amorphous. Optical absorption shows the

presence of an absorption band centered around 850 nm. Photochromic and thermochromic

results are in the process.




335

[ SEM-96 ] Inelastic light scattering in NbS2 and WTe2

transition metal dichalcogenides

Francisco Rodríguez Melgarejo 1 , Aarón Hernán Barajas Aguilar 1 , Martín

Adelaido Hernández Landaverde 1 , Gabriel López-Calzada 1 , Chuck Irwin 2

, Sergio Joaquín Jiménez Sandoval ([email protected]) 1

1 Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro 2 Department of Physics, Simon Fraser University

Transition Metal Dichalcogenides (TMD) are materials with layered structures which consist

of stacks of chalcogenide-transition metal-chalcogenide unit layers bind together by weak

van-der-Waals-type forces. These characteristics have made possible to get two-dimensional

materials with ease by obtaining single molecular layers. Among these, MoS2 and WS2 have

been recently the focus of intensive research efforts from both theoretical and experimental

points of view because of the inherent 2D phenomena that occur in them and because of their

potential applicability. In this work we present a Raman spectroscopy study of crystalline

samples of the two TMD´s. niobium sulfide (NbS2) and tungsten ditelluride (WTe2). The

samples were grown by vapour transport by heating the elements in an evacuated quartz

ampoule. The Raman scattering experiments were performed at room temperature on fresh

surfaces right after exfoliating as-grown crystallites. We report here the Raman spectra of

NbS2 and WTe2 obtained by exciting the samples with 785.0, 632.8, 514.5 and 488.0 nm

laser lines. The Raman bands are discussed in terms of the known lattice vibrational

information and of the applicable group theory.




336

[ SEM-98 ] Nanoelectric and photovoltaic

caracterization of CuInSe2 films doped with active

metals

L.E. Arvizu-Rodríguez ([email protected]) 4 , A. Barón-Miranda 6 ,

F. Caballero-Briones ([email protected]) 6 , S. Jiménez-

Sandoval 2 , I. Diez-Pérez 3 , L. Aguilera-Vázquez 4 , U. Páramo-García 4 , F. Sanz 5 , F. Sanz 1 , F. Sanz 3 , F. Chalé-Lara 6

1 CIBER-BBN, Campus Río Ebro Edificio I+D, Bloque 5, 1a planta, C/Poeta Mariano Esquillor s/n,

50018 Spain . 2 CINVESTAV-IPN Unidad Querétaro, Libramiento Norponiente, Fracc. Real de Juriquilla,

Juriquilla, México. 3 Departament de Química Física, Universitat de Barcelona, Martí i Franquès 1, 08028, Barcelona,

Spain. 4 División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Cd. Madero,

Tamaulipas, Mexico. 5 Institute for Bioengineering of Catalonia (IBEC), Edifici Hèlix, Baldiri i Reixac 15-21, 08028

Barcelona, Spain. 6 Instituto Politécnico Nacional, Laboratorio de Materiales Fotovoltaicos, CICATA Altamira. Km

14.5 Carretera Tampico-Puerto Industrial Altamira. 89600 Altamira, México.

Investigation has been made as to the incorporation of electrically beneficial for CuInSe2 impurities,

such as with sodium doping. It has been found that the grain boundaries of the CIS not create deep

levels and therefore are neutral. However, they have not tested other active dopants that could

improve the performance observed with sodium. In this work they were electrodeposited CuInSe2 the

films on copper substrates using a bathroom with Cu ratios: Se: In 1: 1: 2. To increase crystallinity

and reducer the presence of phases undesirable as Cu-Se or Se films electrochemical post-treatment

were carried to the films applying a negative potential in the presence of Se4+ and subsequently a

potential positive in the same solution[1]. The films were doped with four electrochemically active

metals at three different levels of doping, applying an additional negative potential during deposition.

The films were characterized by Raman spectroscopy, atomic force microscopy with current

measurement (CAFM), IV macro with light without light and photoelectrochemical current. IV

curves and electrical CAFM images by finding an improved rectifying behavior of current with

decreasing charge density of the dopant and local variations in conductivity of the materials are

compared. The effect of doping on the microstructure and photocurrent measurements and

electrochemical photocurrent described.

[1] F. Caballero-Briones, L.E. Arvizu-Rodríguez, A. Palacios-Padrós, S. Jiménez-Sandoval, F. Chalé-

Lara, J.L. Fernández-Muñoz, I. Díez-Pérez, F. Sanz, F.J Espinosa-Faller, Phase and surface

modification by electrochemical post deposition treatments in ultrasonic-assisted CuInSe2/Cu

electrodeposited films properties. Sent: Chalcogenide Letters.




337

[ SEM-99 ] Semiconductor thin films of cds as obtained

by rf sputtering technique in areas 100 CM2 and its

applications in prototype of CdTe pv modules

Erendira Velázquez López 2 , Francisco Cortés Carreón 2 , Lourdes Albor

Aguilera 1 , Jorge Sastre Hernández 1 , José Alfredo del Oso Acevedo 2 ,

Rogelio Mendoza Pérez ([email protected]) 2 , Gerardo Contreras

Puente 1

1 ESFM-IPN 2 UACM

This paper presents the results of processing thin films of cadmium sulfide (CdS) by the use

of the technique of Radio-Frequency (RF) sputtering. This semiconductor is the window

material employed in the Cadmium telluride (CdTe) PV-modules in areas of 100 cm2. The

respective heat treatments with cadmium chloride (CdCl2-TT) and CdTe were performed by

the (Close Spaced Sublimation (CSS) technique; while the metal contacts of copper-

molybdenum (Cu-Mo) on CdTe were deposited by Sputtering-DC technique. The CdS

samples were made with different deposition parameters: substrate temperature, chamber Ar-

pressure, RF-power and CdS thickness. The influence of the deposition parameters are shown

in the photovoltaic response of the samples. The results show that the RF-power, and the

pressure influence the deposition rate, the layer thickness of the material and therefore in PV-

performance with photovoltaic efficiency close to 1%.

KEYWORDS: photovoltaic response, CdS, major area.

* This work was partially supported by FOMIX 2012-2 CONACYT-GDF under project

189282.




338

[ SEM-100 ] Sturm-Liouville formalism in gapless

bilayer graphene superlattices: Transmission and

transport properties.

José Alberto Briones Torres ([email protected]) 2 , René Pernas

Salomón 1 , Rolando Pérez Álvarez 1 , Isaac Rodríguez Vargas 2

1 Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Avenida

Universidad 1001, 62209, Cuernavaca, Morelos, México. 2 Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad,

Esquina Con Paseo La Bufa S/N, 98060, Zacatecas, Zacatecas, México.

We study the transmission and transport properties in gapless bilayer graphene superlattices.

The Sturm-Liouville formalism and the transfer matrix approach are implemented to obtain

the transmission probability, and the Landauer-Büttiker formula to compute the linear-

regime conductance. In particular, we carry out a comparison between the two methods, and

we find that the Sturm-Liouville formalism eliminates the numerical instability present in

transfer matrix method for gapless bilayer graphene structures.

[ SEM-106 ] Determination of band gap in TiO2

nanotubes using three different techniques

Ildefonso Zamudio-Torres ([email protected]) 1 , José de Jesús Pérez-

Bueno 1 , Yuny Meas-Vong 1 , Luis Lartundo-Rojas 2

1 Centro de Investigación y Desarrollo Tecnológico en Electroquímica, S.C., Parque

Tecnológico Querétaro-Sanfandila, Sanfandila, Pedro Escobedo, Querétaro, México. CP

76703. 2 Instituto Politécnico Nacional, Centro de Nanociencias y Micro y Nanotecnologías,

UPALM, Zacatenco México-D.F. 07738, México.

In this research, band gap in TiO2 nanotubes (TiO2 NTs) prepared by mean of anodization in

an organic medium is studied by three different techniques. TiO2 NTs amorphous were

obtaining by mean of anodization, in a bath that containing: 98 % V/V, ethylene glyclol, 2 %

V/V water, and 0.3 % weight NH4F, the voltage applied was 60 V during 2 hours. These

nanostructures have an internal diameter of 90-120 nm and a wall size of 15-20 nm, the

nanostructures showed no crystallographic order, after that the NTs were submitted in heat

treatment (480 °C) an then, by mean of X-ray diffraction was possible to establish that

anatase structure was reached. Raman technique was used to confirm the vibrational modes




339

of anatase phase. Band gap determination was made by mean of three different techniques:

Via UV- Vis spectroscopy from the plot of (αhν)n (where n = 1/2, 3/2, 2, and 3 are for direct

allowed, direct forbidden, indirect allowed and indirect forbidden transition respectively)

versus hν, then extrapolated the straight portion on hν axis at α = 0; the values obtained with

photoluminescence and XPS are compared.

[ SEM-121 ] GaAs/InGaNAs gaussian superlattice solar cells

Carlos I. Cabrera ([email protected]) 2 , Agustín Enciso 2 , David A.

Contreras-Solorio ([email protected]) 2 , Luis M. Hernández 1

1 Facultad de Física, Universidad de La Habana, Colina Universitaria. 10400, La Habana.

Cuba. 2 Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad

Esquina con Paseo La Bufa s/n, C.P. 98060, Zacatecas, ZAC., México.

The dilute nitride (GaIn)(NAs) is a novel material system grown lattice matched to GaAs.

The band gap of GaAs decreases rapidly with the addition of small atomic fractions of N,

moreover, the addition of In to GaNAs does not only provide a lattice matched to GaAs, but

also decreases the band gap. This property makes very attractive the use of GaInNAs

materials to fabricate multiple quantum wells and superlattice to improve the GaAs solar cell

conversion efficiency. In the present work a GaAs p-i-n solar cell is modeled where the i-

region is filled with GaAs/GaInNAs Gaussian superlattice (GSL), the barriers width is

modulated by a Gaussian function. These systems have the outstanding characteristic that the

transmission spectrum presents transparency bands or passbands with almost perfect

transmission.

Using transfer matrix method the tunneling probability as a function of energy was calculated

for GSL. The results show that the spectrum is not substantially distorted by the presence of

the applied electric field. We have used expressions to evaluate the density of states (DOS)

and absorption coefficient corresponding to a GSL under the influence of an electric field

perpendicular to the layers. With the increment of the electric field, the DOS value is

diminished, meanwhile the absorption coefficient is not substantially modified. The

photocurrent was evaluated and our results show that it can reach values which have never

been obtained before for a single junction solar cell. The GSL solar cell conversion efficiency

was computed and it shows high values. Because of the results that our model predictions are

neither compared nor confirmed experimentally, it would be interesting to see if future

experiments will corroborate our outcomes.




340

[ SEM-138 ] Pulsed laser deposition of non-stoichiometric

CdO and the effect of annealing

J.G. Quiñones-Galván ([email protected]) 3 , R. Lozada-Morales 6 , S.

Jiménez-Sandoval 2 , Enrique Camps 5 , V.H. Castrejón-Sánchez 5 , V.H.

Castrejón-Sánchez 7 , V.H. Castrejón-Sánchez 8 , E. Campos-González 4 , M.

Zapata-Torres 1 , A. Pérez-Centeno 3 , M.A. Santana-Aranda 3

1 CICATA-IPN, Unidad Legaria, Mexico D.F.11500, Mexico 2 Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad

Querétaro, Apartado Postal 1-798 Querétaro, Qro, 76001, Mexico. 3 Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de

Guadalajara, Boulevard Marcelino García Barragán 1421, Guadalajara, Jalisco, Mexico, C.P.

44430 4 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, P.O. Box 14-740, México D. F., 07360, Mexico 5 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado postal 18-

1027, Mexico D.F., C.P. 11801 6 Facultad de Ciencias Físico-Matemáticas, Postgrado en Física Aplicada, Benemérita Universidad

Autónoma de Puebla, Av. 14 sur y Av. San Claudio, Col. San Manuel, Puebla, Mexico 7 Facultad de Química, Universidad Autónoma del Estado de México, Paseo Colón y Tollocan,

Toluca, Mexico, C.P. 50110 8 Tecnológico de Estudios Superiores de Jocotitlán, carretera Toluca-Atlacomulco Km. 44.8, Ejido

de San Juan y San Agustín, Jocotitlán, Mexico, C.P. 50700

By means of pulsed laser deposition, a CdO film was grown onto a glass substrate at room

temperature. The mean kinetic energy and the ion density of the laser produced plasma were 75 eV

and 13.5 x 10-12 cm-3 respectively. A laser fluence value of 2 J/cm2 was used. The film was thermally

treated at 500 ºC in air, in order to see the effect of annealing on its physical properties. The structural

properties of the as-grown film indicate that a (200) highly oriented polycrystalline cubic sample was

obtained, which was confirmed by transmission electron microscopy. The annealed sample is still

cubic but it is no longer oriented in the (200) direction. A reduction in grain size for the annealed

sample was observed by scanning electron microscopy. Raman spectroscopy revealed the typical

second order vibrational modes of cadmium oxide which are related to defects. XPS results show the

presence of CdO together with a substoichiometric CdOx phase for the as-grown sample. For the

annealed sample a compensation of oxygen vacancies was observed. Electrical resistivity

measurements give a value of 8.602 x10-4 (Ω cm) for the as-grown film which is in excellent

agreement for cadmium oxide films obtained by physical vapor deposition techniques. For the

annealed sample the electrical resistivity increased to a value of 9.996 x 10-3 (Ω cm). The as-grown

sample has zero transmission in the UV-Visible range as shown by optical transmission

measurements. The photoluminescence spectra of the samples were measured in order to shed some

light on the origin of the zero transmission result.




341

[ SEM-139 ] Structural and optical properties of copper

selenide films grown by co-evaporation

Arlette Casasanero Meléndez ([email protected]) 1 , Jorge Sastré

Hernández 3 , Ma. de los Ángeles Hernández Perez 2 , Jorge R. Aguilar

Hernández ([email protected]) 1 , Gerardo S. Contreras Puente 1

1 ESFM, IPN, Edificio de Física Avanzada, U. P. A. L. M. Col. Lindavista, México, D. F.,

C. P. 07738 2 ESIQIE, IPN, Edificio no. 8, U. P. A. L. M. Col. Lindavista, México, D. F., C. P. 07738

3 ITESM, Edificio de Física Avanzada, U. P. A. L. M. Col. Lindavista, México, D. F., C. P.

07738

In this work we present the results of characterization of copper selenides films grown by co-

evaporation. The substrate temperatures were 300 ºC and 400 ºC. Characterization of samples

was carried out by means of SEM, XRD, EDS and UV-Vis studies. We obtained rich copper

polycrystalline films; the main phases for the 400 ºC set are Cu2-xSe and Cu2Se, on the other

hand, Cu7Se4, Cu2-xSe and Cu2Se are the main phases of the 300 ºC set. Copper atomic

percentage is approximately 60 % for both sets of samples. Through UV-Vis transmission

spectrum we determined that the films are direct band gap semiconductors and the band gap

values are in the range of 1.12-1.46 eV.

[ SEM-162 ] Plasmon-phonon coupling in graphene

superlattices on polar substrates

Gerardo Gonzalez de la Cruz ([email protected]) 1

1 Fisica, CINVESTAV-IPN , Apartado Postal 14-740 Mexico, D.F.

We investigate the role of substrates on the collective excitations of layered graphene using

the self-consistent field approximation. Specifically, we consider graphene layers adsorbed

on polar materials as representative examples of semiconducting and oxide substrates. A new

set of spectrum plasmons originate from the coupling between charge carrier plasmons in

layered graphene structures and optical surface phonon of substrate. It is shown that the

plasmon modes in double-layer graphene structures split into one acoustic mode (w~q) and

two distinct optical modes which one of them displays a behavior more like a phonon mode




342

while the other one vanishes in the long wavelength limit and behaves similar to the optical

plasmon mode present in spatially separated double-layer graphene. On the other hand, the

surface plasmon mode in multilayer graphene coupled via Coulomb interaction with the polar

substrate is discussed in the long wavelength limit and in the weak coupling limit such that

qd>1 where d is the graphene layer separation.

[ SEM-164 ] Synthesis and Characterization of Ga2S3

Thin Films Deposited by Pulsed Laser Deposition at

Different Pressures

Carlos Augusto López Lazcano ([email protected]) 2 , Gibran

Guadalupe Martínez Falomir 2 , Ramon Alvaro Vargas Ortíz 2 , Manuel

Quevedo López 1 , Susana Paola Arredondo Rea 2 , José de Jesus Campos Gaxiola 2 , Jorge Luis Almaral Sánchez 2

1 Department of Materials Science and Engineering, University of Texas at Dallas,

Richardson, TX, 75080, USA 2 Facultad de Ingeniería Mochis, Universidad Autónoma de Sinaloa, Fuente de Poseidón y

Ángel Flores s/n, Ciudad Universitaria, C.P. 81223, Los Mochis, Sinaloa, México.

Thin films of gallium sulfide (Ga2S3) were deposited on glass substrates and silicon by the

technique of pulsed laser deposition (PLD). For deposits, a target of Ga2S3 was used with a

purity of 99.99% and Ar gas inside the general chamber of the equipment. The deposits were

made at different pressures of Ar gas of 0.1 mTorr, 1 mTorr, 10 mTorr, 50 mTorr and 100

mTorr. The thin films obtained have good adhesion, uniform thickness and were free from

microcracks.

The films were characterized by Raman diffraction, Rutherford Backscattering Spectroscopy

(RBS) and x-ray diffraction. XRD results observed that the films have an amorphous

structure, indicating a disordered XMMX packing layers. Raman spectroscopy shows

characteristic curves of Ga2S3 with a mainly monoclinic structure due to vibrations at 224

cm-1 (Vs-GaS4 (A1)) and 300 cm-1 (Vd-GaS4 (A ')). Analysis RBS shows that the thin films

have an atomic ratio of Ga: S = 40:60 indicating that the PLD technique provides high

chemical purity films.

The above results show that the PLD technique is successful for growing stoichiometric

Ga2S3 amorphous thin films, with high purity and good quality.

Keywords: Ga2S3, Pulsed Laser Deposition, Semiconductor, Thin Film.




343

[ SEM-165 ] Synthesis and Characterization of ZnS Thin

Films Deposited by PLD at different pressures

Gibran Guadalupe Martínez Falomir ([email protected]) 2 ,

Carlos Augusto López Lazcano 2 , Ramón Alvaro Vargas Ortíz 2 , Manuel A.

Quevedo López 1 , Adriana Cruz Enríquez 2 , Ramón Corral Higuera 2 ,

Jorge Luis Almaral Sánchez 2

1 Department of Materials Science and Engineering, University of Texas at Dallas,

Richardson, TX, 75080, USA 2 Universidad Autónoma de Sinaloa, Facultad de Ingeniería Mochis, Fuente de Poseidón y

Ángel Flores s/n, Ciudad Universitaria, C.P. 81223, Los Mochis, Sinaloa, México

Thin zinc sulfide films are successfully deposited on glass and silicon substrates using pulsed

laser deposition (PLD) at room temperature under different pressures of argon gas (0.1, 1,

10, 50 and 100 mTorr) and 200 oC at 10 mTorr pressure.

For depositions was used a ZnS target with a purity of 99.99%, argon gas was used in general

chamber at PLD. Argon influence on optical, structural and morphological properties thin

films of zinc sulphide (ZnS), was investigated. The films were characterized by SEM, RBS

and Raman. The SEM showed us the thickness of 100 nm, and the microstructural

morphology was obtained, in which grain distribution on the substrate for film formation is

seen.

The Raman vibrational modes corresponding to ZnS a displacement of 300 cm-1 and a

characteristic vibrational mode of S to 60 cm-1 they were shown. The RBS showed us only

the elements present in the films, Zn and S, which were contained on target. XRD results

indicate that the films have an amorphous structure with small crystalline at room

temperature, to the deposition made at 200 oC has a higher crystallinity. In this study, the

film deposited at a pressure of 10 mTorr to 200 oC is optimal for better crystallinity and better

microstructural system and indicates that the PLD technique provides high purity films.

Keywords: Semiconductor, Thin film, Zinc sulfide, pulsed laser deposition.




344

[ SEM-168 ] TiO2@G photoelectrodes sensitized with

natural pigments for reduction of ammonia in

aquaculture tanks with visible light

Julio Omar Arias Ortiz ([email protected]) 2 , Erick Esaú

Hernández Santiago 5 , Oscar Aarón Márquez González 5 , Rafael Valentín

Tolentino Hernández 5 , Francisco Javier Espinosa Faller 3 , Mariel Gullian

Klanian 3 , Octavio Calzadilla Amaya 1 , Kamaraj Sathish Kumar 4 , Fabio

Felipe Chalé Lara 2 , Felipe Caballero Briones ([email protected]) 2

1 Facultad de Física, Universidad de La Habana. San Lázaro y L, Vedado. 10400 La

Habana, Cuba 2 Laboratorio de Materiales Fotovoltaicos, Instituto Politécnico Nacional CICATA

Altamira, Km 14.5 Carretera Tampico-Puerto Industrial Altamira, 89600 Altamira, México 3 Unidad Experimental Marista, Universidad Marista de Mérida. Periférico Norte Tablaje

Catastral 13941 Carretera Mérida-Progreso. 97300 Mérida México 4 Universidad Politécnica de Aguascalientes, Ingeniería en Energía Calle Paseo San

Gerardo No. 207. Fracc. San Gerardo. Aguascalientes, Ags. México, 20342 5 Universidad Tecnológica de Altamira, Blvd. de los Ríos Km. 3+100, Puerto Industrial

Altamira, 89608 Altamira, México

The degradation of waste nitrogen compounds produced in aquaculture tank is commonly

done through the usa of biofilters (among other methods) to avoid ecosystem poisoning. An

alternative method is TiO2-based photocatalyst to degrade NH3 into N2. On the other hand,

graphene is a material with a high charge transport efficiency which is proposed to enhance

the photocatalyst system efficiency. In this work TiO2 and TiO2@G films were made by

Pechini method onto Fluorine-doped Tin Oxide (FTO), Aluminium-doped Zinc Oxide

(AZO), Stainless Steel (SS) and Soda Lime Glass (SLG) substrates. The molar ratios in the

Pechini solution were 20:5:1 of titanium isopropoxide, citric acid and ethylene glycol

respectively. A mixture of Pechini-TiO2pm25 nanopowder was made and ultrasonically

dispersed until a paste is formed and therefore the paste was deposited on FTO and SS

substrates (≈1cm2) by doctor blade technique and lately calcined up to 450 °C. Some of the

electrodes were impregnated with the ethanolic extract of Laburnum anagyroides Medic.

known as golden rain tree to sensitize it to visible light. Films were characterized by

Reflectance Spectroscopy (RS), X Ray Diffraction (XRD), and current-voltage (I-V) and

photodegradation activity with methylene blue. The results are discussed in terms of substrate

type, graphene presence and sensitization.

Financed by SIP 20151074 and CONACYT 169108




345

[ SEM-172 ] X-ray diffraction studies of CuCdTeO films

deposited at room temperature

Martín Adelaido Hernández Landaverde ([email protected]) 1 ,

Alejandro Montañéz Delgado 1 , Francisco Rodríguez Melgarejo 1 , Gabriel

López Calzada 1 , Sergio Jiménez Sandoval 1

1 Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro, Mexico.

A detailed X-ray diffraction study was carried out on CuCdTeO films deposited by radio

frequency sputtering at room temperature. The use of low growth temperatures is appealing

in the search for inexpensive processes for the growth on technologically important materials.

CuCdTeO films are interesting semiconductor materials because of their ease in tailoring

their optical and electrical properties by varying the relative concentrations of the elemental

constituents. The CuCdTeO films were prepared from targets made of mixtures of CdTe and

CuO powders through cold-pressing processes. The CuO concentrations used in the target

preparation ranged from 0 to 25 at.%. All the films were deposited on Corning 2947 glass

substrates. Glancing angle X-ray diffraction measurements were performed on each of the

as-grown films. Notwithstanding the fact that the substrates were not intentionally heated, all

the films showed polycrystalline characteristics with significant preferential orientation. The

effect of the various [CuO] concentrations on the crystalline structure (i.e. relative abundance

of zincblende and wurtzite phases), preferential orientation characteristics and crystalline

quality are presented and discussed.




346

[ SEM-184 ] Optical and structural characterization of

polycrystalline zinc-selenide thin films grown by pulsed

laser deposition

Patricia Maldonado-Altamirano ([email protected]) 1 , Luis Arturo

Martínez-Ara 1 , María de los Ángeles Hernandez-Perez 2 , Jorge Aguilar-

Hernandez ([email protected]) 1 , Gerardo Contreras-Puente 1 , Fray

de Landa Castillo-Alvarado 1

1 ESFM-IPN Edificio No. 9 UPALM Lindavista C. P. 07738, México D. F 2 ESIQIE-IPN Edificio No. 7 UPALM Lindavista C. P. 07738, México D. F

In this paper results of the processing and characterization of polycrystalline thin films of the

binary semiconductor compound zinc-selenide (ZnSe) grown onto glass, quartz and

crystalline silicon are presented.

ZnSe films were processed by Pulsed Laser Deposition (PLD) technique, under the following

conditions: substrate temperature Ts =400 °C, deposition time td = 30 min, pressure in the

growth chamber P = 1.2x10 -6 Torr, laser = 1064 nm, and repetition frequency 50 Hz.

Structural and optical properties of the films were studied by X-ray diffraction, scanning

electron microscopy (SEM), UV-Vis absorption, photoluminescence (PL) and Raman

spectroscopy. From the analysis of the absorption spectra the value of the band gap Eg = 2.5

eV was obtained. The X-ray diffraction patterns exhibit maxima at 2 = 27.4, 45.5 and 53.76,

corresponding to the zinc-blende structure, a small diffraction peak at 2 = 25.7 was also

observed, it corresponds to the (010) plane of the wurzite structure. The samples also

exhibited room temperature luminescence, which allowed us to carry out a PL study as a

function of temperature, 10-300 K, in order to be able to assign the radiative transitions; a

deep PL analysis is also presented. The observed Raman features have been related to

multiple optical phonon (1LO to 3LO) light scattering.




347

[ SEM-189 ] Optical and structural study of GaN grown

by pulsed laser deposition in nitrogen atmosphere

Luis Arturo Martínez Ara ([email protected]) 1 , Jorge Ricardo

Aguilar Hernández ([email protected]) 1 , María de los Ángeles

Hernández Pérez 2 , Gerardo Silverio Contreras Puente 1

1 ESFM-IPN Edificio No. 9 U. P. A. L. M. Lindavista C. P. 07738, México D. F. 2 ESIQIE-IPN Edificio No. 7 U. P. A. L. M. Lindavista C. P. 07738, México D. F.

Results about processing and characterization of gallium nitride (GaN) films grown by pulsed

laser deposition technique are presented. The films were grown on sapphire (0001) and

silicon (100) substrates, under the following conditions: substrate temperature 850 ° C, time

deposition of 2 minutes, pressure of torr. A Nd: YAG laser was used with =1064

nm, repetition frequency of 50 Hz and power of 2.8 W. To characterize GaN films, diffraction

X rays, UV-Vis spectroscopy and photoluminescence were used. To study the GaN films

structural properties, X-ray diffraction was used obtaining peaks corresponding to GaN and

trace Ga2O3. To study the optical properties, UV-Vis spectroscopy absorption and

photoluminescence were used. From the UV-Vis spectroscopy a band-gap value of 3.2 eV

was obtained. Photoluminescence at room temperature was observed, which allow perform

the study at low temperature, the results of this study are also presented in this work.




348

[ SEM-191 ] Development of planarized ambipolar a-

SiGe:H Thin-film Transistors Technology

Miguel A. Dominguez Jimenez ([email protected]) 1 , Pedro

Rosales Quintero 2 , Alfonso Torres Jacome 2 , Mario Moreno Moreno

([email protected]) 2 , Jose A. Luna Lopez 1 , Salvador Alcantara

Iniesta 1 , Susana Soto Cruz 1

1 Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias,

Benemerita Universidad Autonoma de Puebla (BUAP). Puebla, Mexico. 2 Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Departamento de

Electronica. Puebla, Mexico.

Electronic devices fabricated on flexible and large-area substrates are of great interest for the

research community. Thin-film transistors (TFTs) have a high potential to be integrated in

this technology due to its low-temperature process. Although complementary logic circuits

based on discrete n- and p-type transistors are currently under development, the use of

ambipolar TFTs that work as both p- and n-type transistors can simplify the design and reduce

the cost of the complementary logic circuits. An alternative semiconductor for obtaining

ambipolar TFTs fabricated at low temperature is hydrogenated amorphous silicon-

germanium (a-SiGe:H). This film is barely used as an active layer in TFTs, since a high

content of germanium increases the density of states in the film. However, a low

incorporation of germanium improves some properties of the a-Si:H films, such as electron

and hole mobilities. Our a-SiGe:H films have estimated electron and hole mobilities of the

same magnitude, which indicates a possible candidate for ambipolarity. Since one of the

bottlenecks in this technology is the source/drain contact resistance, different processes have

been implemented in order to improve the main device interfaces. Previously in literature, a

reduction of the contact resistance has been attributed to the planarization of the gate

electrode. In order to provide a physical explanation of this improvement, the electrical

performance of ambipolar a-SiGe:H TFTs with planarized gate electrode by Spin-On Glass

is compared with unplanarized ambipolar a-SiGe:H TFTs, and the properties in the main

device interfaces are analyzed by physically-based simulations. Also, trap density and

characteristic energies for the deep localized states in the a-SiGe:H film are obtained. Finally,

using these parameters the device modeling is presented.




349

[ SEM-192 ] Zinc Oxide Thin-film Transistors

Technology by Ultrasonic Spray Pyrolysis

Miguel A. Dominguez Jimenez ([email protected]) 1 , Francisco

Flores Gracia 1 , Adan Luna Flores ([email protected]) 1 , Jose A. Luna

Lopez 1 , Salvador Alcantara Iniesta 1 , Susana Soto Cruz 1 , Pedro Rosales

Quintero 2 , Mario Moreno Moreno 2

1 Centro de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias,

Benemerita Universidad Autonoma de Puebla (BUAP). Puebla, Mexico. 2 Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Departamento de

Electronica. Puebla, Mexico.

Currently, Zinc Oxide (ZnO) films are attractive to be an alternative to amorphous silicon in

thin-film transistors (TFTs) commercial applications. ZnO films can be obtained by several

techniques such as pulsed laser deposition, sputtering, chemical vapor deposition, etc.

Although some of these techniques allow the deposition of oxide films at room temperature,

they present some technical problems such as low compatibility with large-area substrates

and high-cost. On the other hand, spray pyrolysis offers low-cost, simplicity, compatibility

with large-area substrates and no need of high vacuum. These advantages make of great

potential the use of oxide semiconductors by spray pyrolysis as active layer in TFTs for

transparent, flexible and large-area applications. Although, oxide TFTs fabricated by spray

pyrolysis have already been demonstrated, the temperature of deposition to obtain high

performance devices is still high to be compatible with most of the low-cost plastic substrates

used in the aforementioned technologies. Then, it is necessary reduce the temperature of

deposition at values about 200°C or less in order to be a real alternative for large-area and

flexible applications. In this work, it was used an ultrasonic humidifier and air as carrier gas

to spray the precursor solution onto the TFT structures. The application of ZnO films

obtained by ultrasonic spray pyrolysis at low-temperature (200°C) as active layer in TFTs is

presented, as well, the impact of the gate dielectric thickness and active layer thickness in the

electrical performance of the ZnO TFTs. Also, the annealing effects at 180°C in the

Aluminum-ZnO contacts as function of time were studied. Finally, using a physically-based

simulator (SILVACO), the density of states DOS is modeled to reproduce the experimental

electrical characteristics of ZnO TFTs fabricated by Ultrasonic Spray Pyrolysis. The contact

resistance was experimentally extracted from the ZnO TFTs and included into the simulation,

in order to separate the metal-semiconductor interface contribution from the DOS. A

comparison between the modeled DOS considering the contact resistance and disregarding

it is also presented.




350

[ SEM-196 ] Growth of ZnTe and CdTe nanolayer on

GaSb and GaAs (100) oriented substrates by Atomic

Layer Deposition

Miguel Galvan-Arellano 2 , Joel Díaz-Reyes

([email protected]) 1 , Mario Alberto Flores González 4 , Mario

Villanueva-Ibañez 3 , Roberto Saul Castillo-Ojeda 3


Hacienda de San Juan Molino, Km. 1.5. Tepetitla, Tlaxcala. 90700. México. 2 Depto. de Ingeniería Eléctrica, SEES, CINVESTAV-IPN. Apartado Postal 14-740,

México, D.F. 07000. México. 3 Universidad Politécnica de Pachuca, Km. 20, Rancho Luna, Ex-Hacienda de Santa

Bárbara, Municipio de Zempoala, Hidalgo. 43830. México 4 Universidad Politécnica de Pachuca, Km. 20, Rancho Luna, Ex-Hacienda de Santa

Bárbara, Municipio de Zempoala, Hidalgo. 43830. México.

Among the most successful materials for the detector fabrication are the ZnTe, CdTe and

their respective alloy Cd1-XZnXTe (CZT). These materials in its nanostructured forms are

promising for the production of potential new electronic devices. In addition, it is well known

the high detective quantum efficiency of these materials. With the discovery of the new

properties arising from the nanostructured materials, the growth of nanolayers and

nanostructured materials has gained great importance. ZnTe, CdTe and their alloys, have

proved to be a very important materials for application in this field. Moreover it is possible

to take advantage of the properties of III-V materials as GaAs and GaSb when are used as

substrates of these layered structures. GaSb is an important material used extensively for the

infrared radiation detection. In addition, the lattice parameter is close to the ZnTe, making it

very attractive for its use as substrate; however, it is well known that GaSb surface is rapidly

oxidized introducing additional difficulties for its use. GaAs has been extensively studied III-

V material, with important optical and electrical properties, which can be exploited for device

fabrication in conjunction with the CZT structures. In this work are presented the result

obtained of the growth of ZnTe and CdTe nanolayers on GaSb and GaAs by Atomic layer

Deposition. The results included are Raman spectroscopy and HRXRD in order to study the

crystalline quality and optical properties.




351

[ SEM-198 ] Optical characterization of thin films of

amorphous Cd1-xPbxS from transmittance

measurements

Jorge I. Contreras-Rascón 4 , Joel Díaz-Reyes

([email protected]) 1 , Miguel Galván-Arellano 2 , Verónica

Márquez Buendía 3

1 Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional. Ex-


México, D.F. 07000. México. 3 Instituto Tecnológico de Tehuacán. Libramiento Tecnológico S/N, A.P. 247, Tehuacán,

Puebla. 75770. México. 4 Universidad de Sonora, División de Ciencias Exactas y Naturales, Col. Centro,

Hermosillo, Sonora. 83000. México.

This paper presents the study of the optical constants of Cd1-xPbxS thin films prepared by

chemical bath deposition in spectral range from 300 to 2600 nm, using interferential fringes

of the transmittance spectrum of the film-substrate system. Refractive index, the films

thickness and the absorption coefficient are calculated following Swanepoel´s method. The

dispersion of the refractive index is explained using the single harmonic oscillator Wemple-

DiDomenico model. The absorption edge is found according to the model proposed by Tauc,

from which the value of the optical gap is obtained, also obtaining the optical band gap

values.




352

[ SEM-199 ] Growth and characterization of chemical-

bath deposition Cd1-xPbxS

Froylán Ángel Huerta 3 , Joel Díaz-Reyes ([email protected]) 1

, Jorge I. Contreras-Rascón 4 , Miguel Galván-Arellano 2 , José Francisco Sánchez-Ramírez 1

1 Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional. Ex-


México, D.F. 07000. México. 3 Escuela Superior de Ingeniería Mecánica y Eléctrica, Unidad Culhuacán. Instituto

Politécnico Nacional. Av. Santa Ana 1000, Col. San Francisco Culhuacán, Del. Coyoacán,

México, D.F. 04430. México 4 Universidad de Sonora, División de Ciencias Exactas y Naturales, Col. Centro,


The development of third-generation solar cells overcoming the Shockley−Queisser

efficiency limit for a single absorber, 31%, is one of the most fascinating challenges in the

energy research field. In this aspect, semiconductor quantum dots (QDs) have shown

extremely attractive properties for the development of solar cells overcoming the current

limitations. The demonstration of an efficient multiple exciton generation (MEG) process in

colloidal QDs, despite certain controversy, has aroused a huge interest in the use of these

materials in photovoltaic devices. This interest has been reinforced with the recent reports of

absorbed photon-to-current efficiency (APCE) close to 200% and incident photon-to-current

efficiency (IPCE) as high as 114%. These achievements are acquired by using QDs with IR

absorption, PbS and PbSe. In the former case PbS QDs have been employed in a sensitized

solar cell configuration. An attempt was made to modify the band gap of CdS (~2.4 eV) by

preparing a mixed lattice with a low-band-gap material, PbS (0.3 eV), giving a new set of

materials, CdxPbl-xS. Band gaps as low as -~ 1.9 eV were achieved with increasing x. The

preparation of CdxPbl-xS was carried out by chemical-bath deposition. Structural

characterization studies using X-ray diffraction (XRD), energy dispersion analysis by X-rays

(EDAX), and optical microscopy were performed. The optical-absorption studies used to find

the band gap are also described. The CdxPbl-xS chemical stoichiometry was estimated by

EDS. The deposited CdxPbl-xS showed hexagonal wurtzite crystalline phase, which was

found by X-ray diffraction and confirmed by Raman spectroscopy.




353

[ SEM-200 ] Optical and structural characterization of

CdSe1-ySy deposited at low-temperature by chemical

bath deposition

Jorge I. Contreras-Rascón 4 , Joel Díaz-Reyes

([email protected]) 1 , Miguel Galvan-Arellano 2 , Luis Alberto

Juárez-Morán 3


Hacienda de San Juan Molino. Km. 1.5. Tepetitla, Tlaxcala. 90700. México. 2 Depto. de Ingeniería Eléctrica, SEES, CINVESTAV-IPN, Apartado Postal 14-740,

México, D.F. 07000. México. 3 Facultad de Ciencias Fisicomatématicas, Benemérita Universidad Autónoma de Puebla.

Av. San Claudio y 18 Sur. Col. San Manuel, Ciudad Universitaria. Puebla, Puebla. 72570.

México 4 Universidad de Sonora, División de Ciencias Exactas y Naturales, Col. Centro,


We present the structural and optical characterization of cadmium selenide sulphur (CdSe1-

ySy) deposited by chemical bath deposition (CBD) technique on glass at a low-temperature

(20±2°C). The sulphur molar fraction is varied from 0 to 42.13%. The CdSe1-ySy chemical

stoichiometry is estimated by energy-dispersive X-ray spectroscopy (EDS). The CdSe1-ySy

shows hexagonal wurtzite crystalline phase, which is found by X-ray diffraction (XRD)

analysis and it is confirmed by Raman spectroscopy. The average grain size of the CdSe1-ySy

films were in the range from 1.199 to 1.683 nm that were determined by Debye-Scherrer

equation from W(002) direction and was confirmed by high resolution transmission electron

microscopy (HRTEM). This average grain size indicates a high quantum confinement due to

which is smaller than the Bohr radii of CdS (2.8 nm) and CdSe (4.9 nm). Raman spectra

show two dominant vibrational bands about 208 and 415 cm-1 associated at CdSe-1LO-like

and CdSe-2LO-like. By transmittance measurements at room temperature is found that the

optical bandgap energy varies from 1.86 to 2.158 eV in the range of investigated sulphur

molar fraction. The room temperature photoluminescence presents radiative bands in visible

and a dominant radiative band about 3.0 eV that may be associated exciton bound to donor

impurity.




354

[ SEM-218 ] Photocatalytic degradation of Methyl Red

dye in aqueous solution under UV and solar radiation

using Au doped TiO2

R. Hernández ([email protected]) 2 , C. Guzmán 2 , S. M. Durón-

Torres 2 , K. Esquivel 1 , E. A. Elizalde 1 , A. Domínguez 1

1 Facultad de Ingeniería, Universidad Autonónoma de Querétaro, Cerro de las Campanas,

C.P. 76000, Santiago de Querétaro, Qro., México 2 UACQ – UAZ, CU Siglo XXI Edificio 6, Km 6 Carr. Zac – Gdl, La Escondida Zacatecas,

Zac, C.P. 96160, México

Water pollution is a problem that affect us all, leaving no choice but to seek ways to make

contaminated water again be fit for human consumption. Photocatalytic processes received

great attention in wastewater treatment due to its cheapness, environmental compatibility and

optimal performances. Because of this reason, the present contribution aims to deepen the

knowledge in Au doped TiO2-based systems and their employment in methyl red removal

from aqueous solutions. Au-TiO2 photocatalysts have been synthetized by a microwave

assisted sol-gel method and characterized by means of X-ray diffraction techniques (XRD).

Depending on the weight percentage of dopant (0.01 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1.0

wt%, 5 wt%), some changes in the band gap energy can be observed. X-ray diffractions

patterns were recorded to study the formation of TiO2 crystalline species. The diffraction

peaks detected after the calcination process indicates the presence of the crystalline anatase

phase and no presence of rutile phase was observed. For the Au-TiO2 sample, the peaks

detected in 2θ (38°, 44.2°, 64.4°, 77.2°) indicates the presence of particles of metallic gold.

The catalytic activity was evaluated with respect to methyl red photodegradation in different

conditions as a function of irradiated light (UV, solar), application of an electric current, the

combination of both processes and different concentrations of methyl red aqueous solutions.

The photocatalytic test demonstrate the positive influence of the application of an electric

current to photocatalytic processes. A complete bleaching of the solution was achieved at 20

min using a photoelectrocatalytic method whilst the conventional photocatalytic method

didn’t bleach completely at 90 min of reaction and a conventional electro oxidation method

achieve the complete bleaching at 40 min of reaction.




355

[ SEM-221 ] Size controlled synthesis of In2O3

microcrystals of octahedral shape in vapor-solid growth

process

Jesús Alberto Ramos Ramón ([email protected]) 2 , Rutilo Silva

González 2 , Efraín Rubio 1 , Umapada Pal 2

1 Centro Universitario de Vinculación y Transferencia de Tecnología (CUVyTT),

Universidad Autónoma de Puebla, 24 Sur, C.U., Puebla 72570, México. 2 Instituto de Física, Universidad Autónoma de Puebla. Apdo. Postal J-48, Puebla, Pue.,

México

Micro-/nanometer indium oxide (In2O3) particles of octahedral shape were synthesized

through vapor-solid (VS) method varying the growth conditions, such as growth temperature

(640, 750 and 850 °C) and heating rate (10, 20, 40 and 60 °C/min) using a high temperature

horizontal furnace. A mixture of In + graphite powder was used as precursor, and Ar + O2

(10:1 v/v, 220 sccm) mixture was used as carrier cum reactive gas. The quartz substrates used

as support were put downstream at the lower temperature zone. The morphology and size of

the micro-/nanostructures were analyzed by scanning electron microscopy (SEM). The

composition of the particles was estimated by energy-dispersive spectroscopy (EDS). The

crystallinity and optical properties of the particles were analyzed using microRaman

spectroscopy at room temperature. It has been observed that both the heating rate and growth

temperature affect the final size of the microcrystals without affecting their crystallinity.

We acknowledge the financial supports extended by CONACyT, Mexico (Grant # CB-

2010/161767), and VIEP, BUAP (Grant# VIEP/EXC/2015), Mexico for realizing this

investigation.




356

[ SEM-226 ] Paving the way for an increased photocatalytic

performance of TiO2 in the visible spectral region by surface

chemical modification

Adan Luna-Flores ([email protected]) 1 , Adan Luna-Flores 3 , José Luis Sosa-Sánchez 1 ,

Maritza Méndez-Hernández 3 , Javier Martínez-Juárez 1 , María Josefina Robles-Águila 1 ,

Ligia Catalina Muñoz-Arenas 2

1 Centro de Investigación en Dispositivos Semiconductores del IC-BUAP, 14 sur y Av. San

Claudio, Ciudad Universitaria, Puebla, Pue. A.P. 196, C.P. 72000, MÉXICO 2 Facultad de Ciencias Biotecnoambientales, UPAEP, 21 Sur 1103 Barrio Santiago,

Puebla, Pue. C.P. 72410, MÉXICO 3 Facultad de Ingeniería Química, Benemérita Universidad autónoma de Puebla, Av. San

Claudio y 18 Sur, Ciudad Universitaria, Puebla, Pue. C.P. 72570, MÉXICO

Keywords: Advanced Oxidation Processes, Surface Modified Photocatalyst, Phthalocyanine Dyes.

Recently developed Advanced Oxidation Processes -AOPs- show a great potential for application in

many wastewater treatment procedures. In a general context, AOPs refer to an emerging technology

consisting of chemical procedures designed to remove organic and sometimes inorganic materials in

water and wastewater by oxidation reactions with hydroxyl radicals (•HOs). These AOPs utilize the

very strong oxidizing power of these radical species generated “in situ” to oxidize organic

compounds, in the best case scenario, to the end products of carbon dioxide and water.

In the follow-up of an ongoing project, we present our results on the degradation of Rhodamine B

using a new TiO2 photocatalyst which was modified on its surface with Al to prevent charge carrier

recombination. In addition, a tetracarboxylated zinc phthalocyanine dye -ZnPc- was incorporated

onto the TiO2 surface as an antenna molecule in order to extend the catalyst photo-response to the

visible range.

In the modified photocatalyst system, the absorbed dye can inject electrons into the conduction band

of the semiconductor after visible light excitation. On the other hand, the incorporation of the Al

metal dopant results in an improved trapping of electrons that inhibits the electron-hole recombination

during irradiation. The decrease of charge carriers recombination results in an enhanced photoactivity

for the degradation of Rhodamine B.

The degradation process was monitored by UV-Visible spectroscopy and comparison of the

photocatalytic activity of three different materials TiO2, TiO2/Al y TiO2/Al/ZnPc under the same

degradation conditions show an increased performance in the same order: 15%, 60% y 70%

respectively.




357

[ SEM-232 ] Structural and Optical Characterization of

InAsSb/GaSb Grown by Liquid Phase Epitaxy


Rodríguez-Fragoso 3 , Julio Gregorio Mendoza-Álvarez 3 , Gerardo

González de la Cruz 3 , Rogelio Fragoso-Soriano 3 , José Alberto Andraca-

Adame 1

1 CNMN-IPN 2 FCE-BUAP

3 Physics Department-CINVESTAV

High quality InAs1-xSbx semiconductor films were successfully grown on (100) GaSb single

crystal substrates using liquid phase epitaxy technique (LPE). The crystalline structure and

lattice mismatch between film and substrate were investigated by high-resolution X-ray

diffraction (HRXRD). The surface roughness and the interface morphology of the epitaxial

film-on-substrate were characterized by atomic force microscopy (AFM), scanning electron

microscopy (SEM) and optical microscopy. These results show the high-purity InAs1-xSbx

epitaxial layers with mirror-like surface and rms ranges from 0.5 to 2 nm, and a sharp

interface between substrate a ternary film. The optical properties of the layers were studied

by low temperature photoluminescence (PL) spectroscopy. PL spectrum of the ternary film

shows one radiative emission peak with narrow full width at half-maximum, which is an

evidence of the good crystalline quality of the epilayer. It is worth to mention that the InAsSb

films were grown on GaSb substrates for compositions of Sb with x=0.16 without introducing

any intermediate composition buffer layer between the GaSb substrate and the film as

reported in previous works.




358

[ SEM-242 ] Influence of pH on ZnO nanocrystalline

thin films obtained by CBD method

Bertha Luisa Rivera Flores ([email protected]) 1 , Reina Galeazzi

Isasmendi 1 , Tomás Díaz Becerril 1 , Elia Viridiana Reyes Cervantes 1 ,

Nicolás Rutilo Silva González 2 , Enrique Rosendo Andrés 1 , Crisóforo

Morales Ruiz 1 , Godofredo García Salgado 1

1 CIDS-ICUAP, Benemérita Universidad Autónoma de Puebla. Av. San Claudio y 14 Sur

s/n C.U., Col. San Manuel, Edif. 103-C. Puebla, Pue., 72570, México. 2 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Postal J-48,

Puebla, Pue. México.

In this work, different formation of zinc oxide (ZnO) nanoparticles with wurtzite structure

are reported. Semiconductors such as ZnO, ZnS, and ZnTe have extensive applications in

electronics, photonics and photoelectronics. ZnO nanoparticles are of great interest in both

scientific and technological point of view because of their novel electronic properties.

ZnO nanocrystalline thin films have been prepared on glass substrates by using chemical bath

deposition (CBD) method, at low temperature in aqueous solutions and varying the pH of

precursor solutions from 8 to 11.5 under controlled growth conditions. The nanostructures

obtained at low pH present a grow along c-axis in form of spindle. A higher pH of the reaction

mixtures leads to a better definition of prismatic planes, forming bar-shaped structures. The

analysis show that the surface morphology improves with increase of pH values. The

structural, morphological and optical characterization were performed by X-ray diffraction

(XRD), scanning electron microscopy (SEM) and photoluminescence (FL) respectively. It

was found that with the variation of the pH of the reaction solutions the morphology of ZnO

nanostructures could be controlled.

Keywords:ZnO nanostructures, CBD technique, Wurtzite structure.




359

[ SEM-245 ] Electric-Dipole Spin Resonance dynamics

for an electron confined in a quantum dot

Miguel Ángel Rodríguez Moreno ([email protected]) 1 , Lilia Meza

Montes 2 , David Hernández de la Luz ([email protected]) 1

1 CIDS, BUAP 2 IFUAP, BUAP

Electric-dipole spin resonance or EDSR [1] provides an effective way for manipulating the

electron spin as it has been demonstrated experimentally in nanolitographic quantum dots

[2]. It is based on the spin-orbit interaction that couples the spin degree of freedom with the

orbital motion when a time-dependent electric field and a static magnetic field are applied.

Here, we present a detailed study of this dynamics for one electron in a single quantum dot.

We numerically solve the time-dependent Schrödinger equation in order to analyze the

evolution of an electron spin confined in a single quantum dot, including Rashba and linear

Dresselhaus spin-orbit interactions. Rabi oscillations are observed and their dependence on

different parameters is studied. An analytical approach based on Schrieffer-Wolff theory was

also used, showing qualitative agreement with the numerical one within the limits of the

perturbative approximation. Dependence on the orientation of the electric field with respect

to the crystallographic axes is discussed and conditions for maintaining the system within an

ideal two-level system are proposed.

References

[1] Rashba, E. I. and Efros, A. L., "Orbital mechanisms of electron-spin manipulation by an

electric field". Phys. Rev. Lett. 91, 126405 (2003).

[2] Laird E. A. et al., "Hyperfine-mediated gate-driven electron spin resonance". Phys. Rev.

Lett. 99, 246601 (2007).




360

[ SEM-250 ] Photocatalytic activity of TiOx thick films

prepaed by Dr. Blade method.

E. Morales Ricardez 1 , M. Zapata-Torres ([email protected]) 2 , E.

Valaguez Velázquez 4 , J.L. Fernández Muñoz 2 , O Calzadilla Amaya 3

1 CECYT 6 - IPN, Av. Jardin y calle 4 s/n , C.P. 02950, Mexico D.F. 2 CICATA-IPN, Unidad Legaria, Legaria 694 C.P. 11500 D.F., México

3 Facultad de Física. Universidad de La Habana. San Lázaro y L. CP 10400. La Habana.

Cuba 4 UPIITA-IPN, Av. IPN 2580 C.P. 07340 México, D.F.

TiO2 is a widely used photocatalyst with diverse applications such as air purification,

deodorization, water purification and self-cleaning coatings. TiO2 is a wide band gap (3.2

eV) semiconductor material that shown photocatalytic activity under UV light irradiation.

However, the UV radiation intensity in the solar radiation reaching surface earth is very faint,

just around 5 % of the incident solar energy. Then, producing a photocatalytic TiO2 based

material with a lower band gap could increase its efficiency. Finding novel photocathalytic

semiconductor materials that absorb lower energy photons, in the visible and infrared regions

of the solar spectrum, would allow to use a wider portion of the solar spectrum and as

consequence increasing its effiency. Several studies have reported the red-shift of the band

gap of TiO2 employing several approaches such as doping with diverse metals; doping with

non metallic ions; dye sensitization; mixing with semiconductor quantum dots and

nonstoichiometric mixed phase titania nanocomposites. The improved photoresponse in the

visible region of the solar spectrum of Ti suboxides involves new energy levels of the

semiconductor: Ti3+ defects enhance visible light photoactivity by introducing band-gap

energy states.

TiOx thick films have been deposited on ITO coating corning glass substrates, using Dr.

Blade method. In order to obtain TiOx nanoparticles we used a ball milling of TiO2+NaBH.

The TiOx nanoparticles were annealed at 500 °C in Ar atmosphere. The structural and

chemical bond characteristics were analyzed by X- ray diffraction and X-ray photoelectron

spectroscopy (XPS). UV-Vis diffuse reflectance spectroscopy was employed to determine

the band gap energy. The photocatalytic efficiency was evaluated by the photodegradation

of a methylene blue aqueous solution. The samples showed a photocatalytic activity in the

visible or visible-NIR light spectrum.

This work was supported by SEP CONACYT (projetc 153245) and SIP-IPN (project

20150090)




361

[ SEM-262 ] Optical and electrical characterization of

HCl doping polyaniline

Cesia Guarneros Aguilar ([email protected]) 1 , Miguel A. Dominguez

Crespo 1 , Ana Bertha Lopez Oyama 1 , Edna Carina De la Cruz Terrazas 1

1 CICATA-IPN Unidad Altamira, Carretera Tampico-Puerto Industrial Altamira Km 14.5,

Industrial Altamira, 896000, Altamira Tamaulipas, Mexico

The most of semiconductors are crystaline inorganic solids, however, it has been demostrated

that conjugated organics molecules can exhibit semiconductor behavior. The conducting

polymers have specific properties such as high flexibility, high impact resistance and unique

electronic-optical properties. As a consequence has a potential application in a variety of

advanced devices ranging from organic electronics, sensors, batteries, actuators,

thermoelectrics, to electro-optic and electro-chromatic devices. In this study, it is reported

the synthesis and characterization of a series of HCl (0.5 M, 0.75 M and 1.0 M) doping

polyaniline (PANI) by oxidative polymerization using ammonium persulfate (APS) as

oxidant, and maintaining the reaction temperature in the range from 0° to 3° C. The as-

prepared samples were characterized using X-ray diffraction, IR and UV-vis spectroscopy in

irder to know their structural and optical properties. The electrical characteristics were

analyzed by Hall effect. XRD analysis indicates that all PANI samples exhibit typical

crystalline peak at 25°, whereas the UV-vis spectra show the band absorption in the range

from 240 to 320 nm asosiated to the HOMO-LUMO transition. Finally, the conductivity of

PANI samples were about 6.2, 9.7 and 26.4 S/cm.




362

[ SEM-287 ] Preparation of hybrid material : metal

phthalocyanine sensitized oxide semiconductors by soft

chemistry for enviromental applications

Maria Josefina Robles Aguila ([email protected]) 1 , Adan Luna

Flores 2 , José Luis Sosa Sanchez 1 , Javier Martinez Juarez 1

1 Centro de Investigación en Dispositivos Semiconductores ICUAP-BUAP 2 Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla

Over the last few years, the search for novel nano materials with special physical and

chemical properties has been an important challenge in the field of nanotechnology. A

promising approach is to synergistically combine two or more nano materials into a hybrid

structure.

The hybrids systems TiO2/PcZn and ZnO/PcZn were prepared following a soft chemistry

approach using a solvothermal method assisted by microwave radiation. Results from this

study indicate that changing the irradiation time within the microwave oven, the reagents,

the pH and the incorporation of a surfactant additive in the reaction medium affect the

crystallinity of all the materials obtained.

An asymmetric zinc-phthalocyanine complex of the A3B type was used for sensitization of

the oxides semiconductors. Phthalocyanines (Pcs) are considered very attractive sensitizers

because of their light-harvesting properties in the red and near-infrared (near-IR) spectral

regions and this allows the use of solar radiation to activate the photocatalytic process.

The performance of the system hybrids were evaluated by the photocatalytic degradation

aqueous solutions of Rhodamide B for 240 minutes under irradiation visible light.




363

[ SEM-313 ] Sub-Wavelength Structured Silicon Films

Deposited by RF-PECVD for Photovoltaics

William W. Hernández-Montero ([email protected]) 1 , Carlos Zúñiga 1 ,

Javier De la Hidalga 1 , Wilfrido Calleja 1 , Adrián Itzmoyotl 1

1 Departamento de Electrónica, INAOE, Puebla, México

Solar cell is the key element for the generation of electrical energy from solar radiation.

Basically, a solar cell is a transducer of optical power to electrical power. In this work, we

report the structural and optoelectronic properties of sub-wavelength structured silicon films

prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) for

photovoltaics. Fixed parameters were deposition time of 30 minutes, substrate temperature

of 150 °C, hydrogen flow of 50 sccm, power of 30 W and frequency of 13.56 MHz. The

varied parameters were silane and pressure at high and low levels. Corning glass and p-type

c-Si wafers were used as substrates. Structural characteristics were analyzed by Atomic Force

Microscopy, infrared and Raman spectroscopy. Optical properties were estimated by

transmittance in the UV-Vis region. By the transmission line method under darkness and

illumination conditions, we calculate the photosensitivity for the standard AM1.5. Two

groups of samples with similar characteristics resulted, being the flow of silane the key

parameter. At 100 sccm of silane flow, films with enhanced photosensitivity were obtained

due to the presence of random mesostructures that scatter the light, making the film opaque;

the deposition rate was 0.6 nm/s. These films are appropriate for intrinsic layers in p-i-n

structures for solar cells. At 10 sccm of silane flow, films that included nanocrystalline

regions were obtained; the films exhibited low photosensitivity but high dark conductivity,

which is suitable for p or n-type doped layers.




364

[ SEM-322 ] Morphological Characteristics of Si:H p-i-n

Structures Deposited by PECVD on AZO/Glass

Substrates

Carlos Alberto Ospina Ocampo ([email protected]) 1 , Andrey Kosarev


1 Departamento de electrónica, INAOE, Luis Enrique Erro # 1, Santa María Tonatzintla,

72840 Heróica Puebla de Zaragoza, Pue.

In this paper we present a study of morphological characteristics changes through the various

layers comprising a Si:H p-i-n structure, which has been deposited by PECVD on

AZO/Corning glass substrates and where the transparent conductive oxide is AZO. AFM

measurements were conducted over area of 2 x 2 µm2 to determine morphological

characteristics of the substrates, carbon layer, p-layer, as well as intrinsic layer and finally

the n-layer. The deposition temperature was set at 160°C and frequency 13.56 MHz. AZO is

considered as an inexpensive transparent and conducting material which has been used in

industry for flat-panel displays and solar cells. AZO also serves as ohmic contact and as

reflective and passivation layer, whereby it is possible to improve the efficiency of

photoelectric devices. The behavior of average height, kurtosis and rms roughness

parameters is the same layer by layer and skewness behavior is exactly contrary to these

three. Average height, kurtosis y rms roughness decrease as the number of layers increases

and there is an exception for p-type layer. Skewness increases in value as it grows the number

of layers not being seen this in the p-layer.




365

[ SEM-333 ] Optical and structure characterization of n-

and p-type Ga0.86In0.14As0.13Sb0.87

José Saúl Arias-Cerón 3 , Joel Díaz-Reyes ([email protected]) 1

, Julio G. Mendoza-Álvarez 2 , Patricia Rodríguez-Fragoso 2 , José Luis

Herrera-Pérez 4


Hacienda de San Juan Molino. Km. 1.5. Tepetitla, Tlaxcala. 90700. México. 2 Depto. de Física, CINVESTAV-IPN, Apartado Postal 14-740, México, D.F. 07000.

México. 3 Depto. de Ingeniería Eléctrica, SEES, CINVESTAV-IPN, Apartado Postal 14-740,

México, D.F. 07000. México. 4 Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas. Av.

Instituto Politécnico Nacional 2580, Gustavo A. Madero, Barrio La Laguna Ticoman.

México, D.F. 07340. México

Ga0.86In0.14As0.13Sb0.87 quaternary solid solutions lattice-matched to the GaSb (001) substrate

were grown by liquid phase epitaxy, which were intentionally doped with Te and Zn in a

wide range. Two main vibrational peaks are observed in their Raman spectra over the doping

range investigated. The assignment of the observed modes to GaAs-like and (GaSb+InAs)-

like mixture modes is discussed for each impurity. The comparison of the experimental

results with obtained ones by the modified random-element isodisplacement model allows to

confirm that the peaks correspond to the vibrational modes associated LO and TO of the

binary compounds GaAs and (GaSb+InAs). The photoluminescence for the undoped

GaInAsSb shows three narrow exciton-related peaks with narrow full width at half

maximum, which is an evidence of the good crystalline quality of the epilayers. The low-

temperature photoluminescence of n- and p-type GaInAsSb were obtained as a function of

tellurium and zinc concentrations added to the melt solution. These spectra were interpreted

taking into account the nonparabolicity of the conduction (valence) band. Calculations of the

peak position and photoluminescence transitions were performed. Both the band filled as

well as band tailing effects due to Coulomb interaction of free carriers with ionized impurities

and shrinkage due to exchange interaction between free carriers were considered in order to

properly account for the observed features of the photoluminescence spectra. It is shown that

the band-to-band transition energy can be used to obtain the free carrier concentration in

GaInAsSb, for a wide range of dopant concentration.




366

[ SEM-336 ] Mg-doped GaN and undoped InN Nano-

columns by HCVD

Rafael Garcia Gutierrez ([email protected]) 3 , Godofredo Garcia 2 ,

Oscar E. Contreras 1 , Ricardo Rangel-Segura 4

1 Center of Nanosciences & Nanotechnology, UNAM, Ensenada, B. C. México. 2 Centro de Investigaciones en Dispositivos Semiconductores, BUAP, Puebla, Puebla,

México 3 Departamento de Investigación en Física, Universidad de Sonora,

Hermosillo,Sonora,Apdo. Postal5-088, C.P. 8300, México 4 División de Estudios de Posgrado, UMSNH, Morelia, Michoacán, México

InGaN alloys are ideally suitable for high performance solar cells. Compared with

conventional photovoltaic materials such as InGaP and InGaAs, the band gap of InGaN can

be tuned from 0.7 to 3.4 eV, covering the full solar spectrum. These alloys exhibit excellent

transport properties and show much less deterioration in their optical and electronic

properties.

In this work we present a low-cost, large-area deposition method, using a halide chemical

vapor deposition technique to grow columnar nanostructures of un-doped and doped GaN

and InN. These columns show a cathodoluminescence (CL) and photoluminescence (PL)

peak at 3.52 eV, in the un-doped samples. That corresponds to the donor bound exciton

(DoX). The Mg-doped sample does not show the D°X being the donor acceptor pair (DAP)

at ~3.25 eV the dominant emission as it is common in the heavily Mg-doped GaN. Also is

possible to observe in this spectrum the blue luminescence related to Mg complex as deep

donor. In both CL and PL analysis is possible to observe that the luminescence intensity of

the Mg-GaN is superior to the luminescence of the un-doped or unintentional doped GaN.

Therefore we concluded that Mg as dopant improves luminescence of GaN as phosphor.




367

[ SEM-340 ] Construction of CdSSe/GO multilayer thin

films for hybrid solar cells

Rafael Valentin Tolentino Hernandez 1 , Rafael Valentin Tolentino

Hernandez 3 , Oscar Arón Márquez González 1 , Oscar Arón Márquez

González 3 , Javier Armando Barón Miranda 1 , Nereyda Elizabeth Martínez

García 1 , Ernesto Silva Galaviz 3 , Sathish Kumar Kamaraj 2 , Fabio Felipe

Chalé Lara 1 , Felipe Caballero Briones ([email protected]) 1 , Jesus Guerrero Contreras 1

1 Instituto Politecnico Nacional, Laboratorio de Materiales Fotovoltaicos, CICATA

Altamira 2 Universidad Politécnica de Aguascalientes

3 Universidad Tecnológica de Altamira

Multilayer films of graphene oxide (GO) and cadmium selenide nanoparticles (CdSSe) with

and without molecular functionalization linkers were prepared by sequential electrophoretic

deposition and dip-coating techniques for applications in hybrid solar cells. CdSSe

nanoparticles were prepared by glycerin mediated precipitation and later functionalized with

1,8-octanedithiol or 6-mercapto-1-hexanol. Electrophoretic deposition of graphene oxide

was done from a commercial graphene oxide suspension or from surfactant-assisted

mechanically exfoliated graphene onto fluorine-doped tin oxide or aluminium-doped zinc

oxide substrates either commercial or prepared by spray pyrolysis. The obtained films were

characterized by UV-Vis spectroscopy, scanning electron microscopy (SEM), energy

dispersive X-ray spectroscopy (EDS) and atomic force microscopy. The photocurrent

response was also tested either making a solid device setting the film between two conductive

substrates or in front of a sulfide/polysulfide electrolyte. The UV-Vis measurements showed

that there is a decrease in the transmittance of the film compared to the transmittance of the

substrate without deposition and this decrease varies depending on the molecular linker

selected for the functionalization of nanoparticles. The SEM images show different

integration of the nanoparticles also in function of the molecular linker.

Financed by: SIP 20151074 grant.




368

[ SEM-342 ] CdSe/CdS diode by Successive Ionic Layer

Absorption and Reaction (SILAR) and Chemical Vapor

Deposition (CVD)

Iker Rodrigo Chávez-Urbiola ([email protected]) 1 , Yurii

Vorobiev 1 , Rafael Ramírez-Bon 1

1 Cinvestav-Qro

Research in thin films solar cells and photo-sensors implies a development of different

hetero-junctions between p-type and n-type semiconductor; the different growth techniques

also are important, so that the same material can have different characteristics depending on

the particular technique, like strains, morphology, grain size, porosity, adherence, among

others. All these characteristics can affect the junction of two different materials, even in

some cases one film can reject a subsequent film due to their characteristics or the growth

techniques, so a good compatibility is important between materials and growth techniques.

A heterojunction with p-type cadmium selenide having hexagonal crystalline structure is

quite suitable for an absorber layer in a solar cell system due to its similarity with cadmium

telluride; the cadmium selenide presents a direct band gap (1.7 eV), high absorption

coefficient and photosensitive nature.

In this work we study the heterojunction formed between CdSe and CdS; also we present an

alternative way to synthesize hexagonal CdSe by a combination of techniques (Successive

Ionic Layer Absorption and Reaction (SILAR) and Chemical Vapor deposition(CVD)) where

each technique has its own advantage: SILAR easily provides films with good adherence,

uniform morphology and high thickness control, and with CVD normally gives large grain

size and high deposition rate. The CdS layer was obtained by a classical chemical bath

deposition (CBD).The films developed were characterized by X-Ray diffraction (XRD),

Scanning Electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and the

optical reflection spectra recorded in the wave length range 600-800 nm. Electrical properties

were found from Hall measurements. The I–V characteristics were obtained using an Agilent

semiconductor parameters analyzer. The applied bias voltage varied between −5 V and + 5

V, measurements being taken every 10 mV. The resultant CdSe films are homogenous with

good adhesion to the substrate and hexagonal crystalline phase with a band gap of 1.7 eV. It

is noteworthy that these films have a large thickness up to 20 micrometers and the grain size

2-3 micrometers with hexagonal shape. All these characteristics of the CdSe films, which are

difficult to attain with a single deposition process, are quite suitable for applications in

absorption layers in thin film solar cells. The device CdSe/CdS shows a satisfactory behavior

as diode at 300K.




369

[ SEM-367 ] Stacking Vertical of heterojunctions bulk of

organic semiconducting materials and CNS, to build

OFETs.

Ramón Gómez Aguilar ([email protected]) 2 , Gerardo

Ortega Cervantes 1 , Adrian A. Castañeda Galván 2

1 Departamento de Física, ESFM-IPN, U.P.A.L.M. Zacatenco, U.P.A.L.M. Zacatenco,

México D.F., C.P. 07738. 2 Departamento de ciencias Básicas. UPIITA-IPN, Av IPN No. 2580, Col. Barrio la Laguna

Ticomán, Gustavo A. Madero, México D.F C.P. 07340.

Over the years, new technologies have been trying to use inexpensive materials, such as some

types of carbon-rich substances, including certain polymers to create organic semiconductors

capable of performing the same functions than more expensive technologies based on silicon,

at a rate as close as possible to that achieved with the latter.In order to design, build and

analyze organic light emitting field effect transistors (OLEFET), Arises the design of the

device OLEFET in flexible substrate in different architectures using thin films of the polymer

MEH-PPV and MWNT like a bulk heterojunction prepared in solution in aromatic solvents,

deposited by different methods, innovating design with the use of a transparent film of carbon

nanotubes and graphite flakes as gate elements, source and drain. Emission properties and of

current-voltage (I-V), as well as, the combined effects of source-drain voltage and gate

voltage were analized to finally build the luminescent flexible device according to

predesigned patterns. The OLEFETs show great potential for technological applications in

optoelectronics and active-matrix displays. Organic light emitting transistors are constructed

based semiconductor MEH-PPV and carbon nanotubes multi-walled (MWCNTs) and gate

and / or source-drain electrodes deposited on a flexible substrate film of PET. The devices

were electrically and optically characterized. MWCNTs were synthesized by microwave

irradiation technique. A mixture of graphite powder and bimetallic catalyst (CoMo). CNTs

were deposited on a flexible substrate as a thin film, to be used as gate. The architecture used

was vertical, ITO / PEDOT: PSS / MEH-PPV:CNT-CoMo/ Gain / PMMA / CNT-CoMo.

One of the important conclusions is that in these transistors, we can see in the source-drain

current a linear behavior below 300mV and a regimen of saturation below 1 Volt, results that

allow modular current at low gate voltages. The second is the importance of the sensitivity

to ambient light, which makes it a candidate to be an opto-transistor competent. Finally, the

response to the presence of O2 among other environmental gases allow us to think in a broader

application as gas detectors transistors. All these phenomena are made present in its response

I-V characteristic of our devices.




370

[ SEM-376 ] Amorphous iron oxide/sulfide (a-FeO/S) thin

films via chemical bath deposition: characteristics and

properties

D. A. Mazón Montijo ([email protected]) 1 , M. T. S. Nair 1 , P. K. Nair 1

1 Instituto de Energías Renovables - UNAM

Iron oxide is known for its wide variety of phases, each of which with its chemical and

physical properties that are functions of their crystalline structure and chemical composition.

The versatility of iron oxide includes the interest in its amorphous phase. The amorphous

iron oxide (a-FeO) films are especially used as precursor-films for other iron oxide phases

and even for iron sulfide or disulfide films. Moreover, they have also been studied for their

properties and functionality in photoelectrochemical devices. To improve the performance

of devices based in these materials, research works have been done to modify their electronic,

optical, electrical and charge carrier transport properties through adding cationic and anionic

doping agents such as Al, Ni, Ti, Sn, S and Se. In this work, we present the preparation and

characterization of chemical bath deposited iron oxide/sulfide (a-FeO/S) thin films. The films

were deposited on glass substrate at 40 °C at different deposition time. The chemical bath

contained ferric nitrate, sodium thiosulfate, hydrochloric acid and triethanolamine at pH ~ 7–

8. Uniform thin films deposited on both sides of the glass substrate appear orange-yellow in

daylight and with amorphous structure. The films thickness presented a typical tendency to

increase from 120 to 315 nm with the increase of deposition duration from 0.5 to 2.5 h. The

work will deal with show the details of the chemical composition, morphology, optical and

electrical properties of the films. All features and properties presented by the a-FeO/S films

can be exploited for their use in photovoltaic and/or photoelectrochemical devices.




371

[ SEM-377 ] Photoluminescence spectroscopy study of n-

type GaSb passivated by acid Mercaptosuccinic

Delia María Hurtado-Castañeda ([email protected]) 4 , Fabiola

Vázquez-Hernández 1 , José Saúl Arias-Cerón 2 , José Luis Herrera-Pérez 3 ,

Daladier Alonso Granada-Ramírez 5 , Juan Pedro Luna-Arias 1 , Julio

Gregorio Mendoza-Álvarez 5

1 Department of Cell Biology, CINVESTAV-IPN. México, D. F. 07000, México 2 Department of Electrical Engineering-SEES, CINVESTAV-IPN. México, D. F. 07000,

México 3 Instituto Politécnico Nacional-UPIITA, Av. IPN 2580, Col. La Laguna Ticomán, México

DF 07340 4 National Institute of Astrophysics, Optics and Electronics, Luis Enrique Erro # 1, Santa

María Tonantzintla, Puebla-México, 72840 5 Physics Department, Cinvestav-IPN, A.P. 14-740, México DF 07000

In this work, we have studied the influence of mercaptosuccinic acid (MSA) passivation on

the surface of n-type (100) GaSb single crystals doped with Te at concentrations of around

5x1017 cm-3, through the low temperature photoluminescence (PL) spectroscopy. After a

cleaning process of the GaSb substrates to remove the oxides layers, the samples were treated

at different times using an aqueous solution of MSA. By measuring the PL intensity change

as a function of the aqueous MSA treatment times we can optimize the MSA passivation time

on the surface of the GaSb single crystals, measuring the efficiency of the aqueous MSA

passivation, through the measurement of the PL intensity for the different passivation times.

The effect of different treatment times of the GaSb surfaces on the surface recombination

velocity was investigated using low temperature PL spectroscopy. Finally, we described the

variation as a function of the passivation time of the relative contribution to the PL intensity

of the different transitions involved in the passivation process.




372

[ SEM-379 ] Effect of deposition temperature on the

formation of the SiO2/ZnO/SiO2 heterostructure by

reactive RF sputtering.*

R. Escobedo-Alcaraz 1 , C. Atzin-Mondragon 1 , A.P. Chavelas-González 4 ,

A. Hernández-Hernández 2 , L.A. Hernández-Hernández 3 , A.R. García-

Sotelo 1 , M. Meléndez-Lira ([email protected]) 1


México 2 Escuela Superior de Apan, Universidad Autónoma del Estado de Hidalgo, Calle Ejido de


U.P. Adolfo López Mateos, Col. San Pedro Zacatenco, C.P. 07730 México DF, México 4 Universidad Politécnica del Valle de México, Av. Mexiquense s/n, esquina Av.

Universidad Politécnica, Col. Villa Esmeralda, C.P. 54910, Tultitlán, Estado de México.

The roughness associated with the sputtering deposition process has been employed to

explore the possibility to produce ZnO nanoparticles embedded within a silicon oxide matrix

on soda-lime glass and p-silicon substrates. Silicon dioxide and metallic Zn films were

deposited employing silicon and zinc targets. An oxygen rich working plasma was

employed. A sequential deposition of SiO2/Zn/SiO2 films were deposited ; SiO2 layer was

produced at 400 °C while deposition temperature of Zn layer was changed between 100 and

500 °C. We present results of the chemical, structural and electronic properties. Results

indicated the successful production of ZnO with properties depending on temperature.





373

[ SEM-386 ] Genetic algoritms for solve reflectance

spectrum for porous silicion multilayers

Cristian Felipe Ramírez Gutiérrez ([email protected]) 1 , Mario

Enrique Rodríguez García ([email protected]) 1



The porous silicon (PS) multilayers are a heterostructure made through electrochemical etch.

The electrochemical etch route for doing PS films is very sensible to different parameters

like: HF/surfactant ratio, electrolyte temperature, current density, resistivity among other,

and it is usually characterized by UV-VIS reflectance. However, neither electrochemical

process or UV-VIS spectrum provide direct information about the thickness and porosity of

the films, for these reason we develop an algorithm based in genetic algorithms (GA) to

fitting the UV-VIS.

The GA can fit the UV-VIS spectrum in the range of 1100 to 200 nm for a heterostructure

composed by PS film and Si substrate using as parameters the following chromosome:

where p is the porosity, d the thickness, and and are the RMS roughness of the

interfaces air/PS and PS/SI respectively, and using like penalty function the optical response

stimulated by characteristic matrix method and any effective medium theory that have been

the best fit.

In this work we show the simulation and fit of optical response for four differents films of

PS and we compared the results with SEM.




374

[ SEM-387 ] Defect photoluminescence in ZnS films

Berenice Y. Valles Pérez 1 , Aarón Hernán Barajas Aguilar 1 , Francisco

Rodríguez Melgarejo 1 , Martín Adelaido Hernández Landaverde 1 , Gabriel

López Calzada 1 , Sergio Joaquín Jiménez Sandoval 1

1 Centro de Investigación y de Estudios Avanzados del IPN, Unidad Querétaro

Zinc Sulfide (ZnS) is a well-known luminescent semiconductor material, having prominent

and promising applications in displays, sensors, blue-light emission devices and as window

layer in thin-film solar cells [1-3]. Some of its advantages include low cost and non-toxicity.

It exhibits wide optical transparency from the ultraviolet to the infrared. This optical

transparency combined with its chemical and thermal stability makes ZnS a strong candidate

for its use as window layer in hetero-junction photovoltaic cells [1]. Structural defects,

especially vacancies, exist commonly in ZnS crystals due to variations in temperature and

pressure during the crystallization process. The defect density influences the electronic

properties and, therefore, affects the ZnS physical and chemical properties [4]. In the present

work we report the growth by RF sputtering of ZnS thin films as well as their luminescent

properties at room temperature and at 80 K. Substrates were made of Corning glass and kept

at various temperatures during growth (RT, 200 and 300 °C). The deposition time, RF power

and total pressure were kept constant during depositions. To promote the formation of zinc

or sulfur vacancies the targets were made from different mixtures of ZnS and adding

controlled quantities of Zn or S powders. The structural properties were characterized by X-

ray diffraction. The optical properties were determined by UV-VIS and photoluminescence

spectroscopies.

[1] H.M.M.N. Hennayaka,Ho Seong Lee, Thin Solid Films 548 (2013) 86-90.

[2] V.L. Gayou, B. Salazar-Hernandez, M.E. Constantino, E. Rosendo Andrés, T.

Díaz.Vacumm 84 (2010) 1191-1194.

[3] Rengang Zang, Baoyi Wang, Long Wei. Vacumm 82(2008) 1208-1211.

[4] Jinhuan Yao, Yanwei Li, Ning Li, Shiru Le. Physica B 407 (2012) 3888-3892.




375

[ SEM-397 ] Structural, optical and electrical

characterization of Li doped PbS thin films.

Melissa Chavez Portillo ([email protected]) 1 , Mauricio Pacio

Castillo ([email protected]) 1 , Hector Juarez Santiesteban 1 , Oscar

Portillo Moreno 2 , Xavier Matthew 3

1 CIDS BUAP 2 Ciencias Quimicas BUAP

3 IER, UNAM

Lithium (Li+) doped Lead sulfide (PbS) thin films were prepared chemical bath method. The

concentration of Lithium in the precursor solution of Lead Sulphide was varied from 3mls to

6mls. The structural properties of as deposited films were characterized by X-ray diffraction.

XRD patterns indicated the presence of cubic phase PbS with preferential orientation along

(111) plane. Optical absorbance in visible region of the film increases with dopant

concentration. The optical measurements reveal that the PbS:Li thin films possess direct band

gap and the band gap energy increases with an increase of Li+ concentration. Thin films were

found to be 1.8, 2 and 2.1 eV respectively. The dc conductivities of PbS and PbS:Li thin

films are measured in temperature range 10–40 K. It is observed that the thermal conductivity

increases at with an increase of Li content in PbS system. The experimental data suggests

that the conduction is due to thermally assisted tunneling of the charge carriers in the

localized states near the band edges. The activation energy and optical band gap are found to

increasae with increasing Li concentration




376

[ SEM-398 ] Deposit and characterization of metal

oxides on silicon porous for use in gas sensor

Raul Juárez nahuatlato ([email protected]) 1 , Godofredo García 3 ,

Mauricio Pacio 3 , Crisoforo Moroles 3 , Tomas Díaz 3 , Enrique Rosendo 3 ,

Valentín López 2 , Gabriela Nieto 3

1 BUAP 2 CIBA-IPN

3 ICUAP

ZnO particles supported on a porous silicon structure and used as ethanol sensor is presented

in this work. ZnO particles obtained in a colloidal solution were mixed with the traditional

ethanoic solution of hydrofluoric acid (1:2:2) to obtain porous silicon. Another colloidal

solution mixed with formaldehyde and hydrofluoric acid was used too (1:2:2). XRD,

FTIR, and UV-vis spectroscopy were used to corroborate the presence of the ZnO particles

in the porous silicon matrix. Gravimetry measures were obtained to control the porosity and

thickness of the porous silicon with ZnO particles layer, in both solutions. Porous silicon

with ZnO particles sensors were obtained in normal and free standing layers, showing a better

response that sensors obtained without ZnO [1][2][3]. It is concluded that the ZnO particles

growth on the porous silicon surface enhanced the oxide-reduction mechanisms giving place

to an increase in the conduction response of the sensors in presence of ethanol.

[1]. O. Bisi, S. Ossicini and L. Pavesi, Surf. Sci. Rep. 38,1, 2000

[2] D. Bellet, G. Dolino, Thin Solid Films 276 (1996) 1.

[3] Dazhi Sun, Minhao Wong, Luyi Sun, Yuntao Li, Nobuo Miyatake, Hung-Jue Sue,

“Purification and stabilization of colloidal ZnO nanoparticles in methanol” J Sol-Gel Sci

Technol (2007) 43:237–243.




377

[ SEM-403 ] Solvothermal synthesis of the ternary

compound ZnHgS

E. A González de la Torre 1 , A. Pérez-Centeno 1 , Arturo Chávez-Chávez 1 ,

José Quiñones-Galván 1 , Miguel Ángel Santana-Aranda


1 Departamento de Física, CUCEI, Universidad de Guadalajara

The sulfide ternary compound ZnHgS is a promising material for optoelectronics

applications which has been barely studied because of the difficulties involved on its

synthesis; or even more, its thin film deposition. Quite few reports involving this compound,

that could be useful in a wide range of the electromagnetic spectrum (from 0.5 to 3.7 eV),

have been published. Back in 1960, Kremheller et al. (J. Electrochem. Soc. 107, 12) reported

a hydrothermal process to obtain some concentration values of the ternary, starting with

mixtures of the binary compounds, ZnS and HgS. In this work, we propose a solvothermal

process in ethanol-water mixtures, by mixing the binary compounds, for comparison, and

different combinations of reactant sources for zinc, mercury and sulfur. The crystalline

structure of the samples was characterized by X-ray diffraction and Raman; the morphology

with scanning electron microscopy images; and the band gap was estimated from UV-Vis

measurements.

Acknowledgements: Authors want to thank the technical support of Sergio Oliva. This work

was partially supported by CONACyT (grant CB2010-156773) and U. de G. (programs pro-

SNI and PROINPEP).




378

[ SEM-406 ] A study of Ge nanocrystals embedded

within a SiO2 matrix produced by RF sputtering.*

A. García-Sotelo 1 , E. Campos 1 , S. Gallardo-Hernandez 1 , A. Hernández-

Hernández 2 , J.L. Enríquez-Carrejo 3 , P.G. Mani-Gonzalez 3 , J.R. Farias-

Mancilla 3 , M. Melendez-Lira ([email protected]) 1

1 Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, México, DF 07000,


Chimalpa Tlalayote S/N Col. Chimalpa, Apan, Hidalgo. México 3 Universidad Autonoma de Ciudad Juarez- IIT, Departamento de Física y Matemáticas. Av

del Charro 450 norte. Cd. Juárez, Chihuahua. México. CP 32310.

The characteristics of germanium, mainly its compatibility with silicon technology and the

sensitivity of its band structure to confinement confer a high attractive to the synthesis of

germanium nanostructures. The samples were prepared on p-type Si (1 1 1) substrates by

reactive sputtering. Structural characterization was carried out by grazing angle X-ray

diffraction. Surface roughness was quantified by atomic force microscopy and correlated

with micro Raman spectroscopy imaging. Micro-Raman mapping allow to obtain the Ge

nanocrystals distribution. XPS indicates that there is a transition layer with a gradual

composition around Ge nanocrystals. SIMS results are well correlated with the Ge depth

distribution observed by micro-Raman imaging. IvsV and spectral response results are

correlated with the size and spatial distribution of Ge nanocrystals. TEM micrographies

indicate the presence of unstable phases of Ge.





379

[ SEM-408 ] SIMS and HRXRD study of the deviation

from the Vegard’s law of GaNAs layers grown by PA-

MBE

José Angel Espinoza Figueroa ([email protected]) 1 , Estebán Cruz Hernández

([email protected]) 1 , Salvador Gallardo Hernández 2 , Eliseo García Ramírez 1 ,

Miguel Angel Vidal Borbolla 1 , Máximo López López 2 , Víctor Hugo Méndez García 1

1 CIACyT, Universidad Autónoma de San Luis Potosí 2 Departamento de Física, CINVESTAV

The incorporation of Nitrogen (N) in GaAs is a very important topic in the recent years for

the realization of the quaternary material that includes GaNAs such as GaNAsSb, InGaNAs

and GaNAsP. These materials has an remarkable relevance for the development of new

optoelectronic devices due to the property of Nitrogen (N) of decreasing the bandgap of

GaAs, allowing the so-called bandgap engineering, and for relieving the lattice strain when

coupled to GaN. For GaNAs layers diverse parameters are involved to achieve an optimal

growth like nitrogen flux pressure, Ga/As ratio, growth rate, N RF power, doping and growth

temperature. Each one of these parameters can modify the characteristics of the GaNAs

layers in such a way that the Vegard Law is not longer followed by this material. In this work,

GaNAs films were grown by Molecular Beam Epitaxy (MBE) using GaAs (100) as substrate.

After desorption at 580°C, a 500 nm buffer layer of GaAs was grown, in order to obtain a

flat surface, then 100 nm-thick of GaNxAs1-x layers were grown at temperatures ranging from

400 to 600 °C. The crystal quality of the films was evaluated by High Resolution X-Ray

Diffraction (HRXRD) and for the measurement of the N incorporated Secondary Ion Mass

Spectroscopy (SIMS) was performed. The results obtained by HRXRD were analyzing with

Vegard’s Law, by performing simulations based on the dynamical theory. We found that the

concentrations vary from 1.16 to 3.1% of N incorporated into the GaAs matrix. But when we

compare the SIMS and HRXRD results, we found that for the samples grown at low

temperatures (<500 °C) the concentrations are higher than that obtained by the HRXRD

simulations. Conversely, the samples grown at higher temperatures the N concentrations are

almost the same as obtained from both techniques. This deviation from the Vegard’s Law

could be caused by the very nature of N. When the Nitrogen is incorporated into the GaAs

lattice, it does in different ways: the N not only occupy sites of Arsenic (As) as expected, but

can also occupy sites of Gallium (Ga) and form different bonds like Ga-N, As-N and even

N-N in both the lattice or in interstitial sites. We explain the discrepancy between the SIMS

and HRXRD results as a consequence of the N incorporation in interstitial sites.


SOL 22, FRC-UASLP, INFR-2015-01: 255489, PNCPN2014-01: 248071 and CB: 168761.




380

[ SEM-416 ] Silicon-on-insulator Self-Switching Diode

analyzed by TCAD-simulations

Irving Eduardo Cortes Mestizo ([email protected]) 1 , Joel

Briones 2 , Edgar Briones 1 , Víctor Hugo Méndez García


1 CIACyT, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78210 SLP, México 2 Instituto de Estudios Superiores de Occidente, Guadalajara, 45604 GDL, México

The manipulation of surface states, surfaces charge and depletion zone allows to develop a

surface-states engineering such as the Self-switching diode (SSD) device developed by A.

M. Song [1]. In that device a nano-channel between two L-shape insulating grooves is

fabricated by electron beam lithography. The depletion zone caused by surface states in the

groves, lets the current flux only in one direction. The SSD exhibits the advantage of high

frequency cut-off and simplicity of fabrication. Even when the SSD has been extensively

studied in III-V heterostructures for THz applications, the working principle of the device

permits the use of cheap and widely applied bulk-materials like silicon. In this work the DC

and AC performance of Silicon-on-insulator (SOI)-based SSD are evaluated by TCAD

software. Simulation indicates that the geometrical shape and size of the grooves have a

strong effect on the performance of the device. The viability of modifying the turn-on voltage

in the diode-like current-voltage characteristic from ~0 to 1 V by controlling the surface

density and/or the SSD geometry is demonstrated in the DC-injection mode, where the

relationship between channel width and surface-charge is the key issue. The AC performance

is determined by the vertical grooves widths, a large width propitiates higher frequency cut-

offs. Transient simulations verify the viability of use the SSD as a half- and full-wave rectifier

by the correct array of SSDs. Three-dimensional simulation in conjunction with a self-heating

model are used in order to define the appropriate silicon layer thickness of the devices that

improve the current-voltage response and reduce the typical thermal issues of SOI

technology. This numerical study indicates that SOI technology can be applied to the SSD

concept and the way to determine the best geometry for a desire application improving the

DC and AC response.

[1] A. M. Song et al. Appl. Phys. Lett. 83, 1881 (2003).






381

[ SEM-446 ] Incorporation of Ag nanoparticles in

solvothermal-assisted spin coated TiO2 layers

E. A. González-De-La-Torre 1 , K. Y. Sillas-Montaño 1 , J. G. Guiñones-

Galván 1 , G. Gómez-Rosas 1 , M. A. Santana-Aranda 1 , A. Pérez-Centeno


1 Departamento de Física, Centro Universitario de Ciencias Exactas e Ingeniería –

Universidad de Guadalajara (CUCEI-UDG). Guadalajara, Jal., México

TiO2 is a semiconductor material with extraordinary optical properties which are dependent

on its size and crystalline structure. It is the reference material for photocatalytic activity,

furthermore, it is a suitable material for solar cell applications. In this work, we analyze the

structural, optical and morphological properties of TiO2 films deposited by spin-coating on

glass substrates, using titanium n-propoxide diluted with isopropanol. In order to crystalize

TiO2, we compared samples solvothermally pre-treated with conventional calcination

process. We analyzed the quality of the film, in particular the surface coverage. We also

compared the influence of time and synthesis temperature. Finally, the incorporation of Ag

nanoparticles, produced by laser ablation in water, within the TiO2 layers was explored. XRD

and Raman spectroscopy were used to analyze the crystalline structure. The optical and

morphological properties were studied through UV-Vis spectroscopy and SEM images,

respectively.

Authors want to thank the technical support of Sergio Oliva. This work was partially

supported by CONACyT (grant CB2010-156773) and U. de G. (programs pro-SNI and

PROINPEP).




382

[ SEM-480 ] Electrochemical properties of TiOx thin

films deposited on different metal substrates.

E. Valaguez ([email protected]) 4 , M. Zapata - Torres 1 , E. Hernández

Rodríguez 2 , J.L. Fernández Muñoz 1 , O. Calzadilla Amaya 3

1 CICATA-IPN, Unidad Legaria, Legaria 694 C.P. 11500 . México D.F. 2 Departamento de Física Aplicada, CINVESTAV-IPN, Unidad Mérida, Km. 6 Antigua

carretera a progreso. C.P. 97310, Mérida, Yucatan, México. 3 Facultad de Física. Universidad de La Habana. San Lázaro y L. C.P. 10400. La Habana

Cuba 4 UPIITA-IPN, Av. Instituto Politécnico Nacional 2580. C.P. 07340. México D.F.

Titanium Dioxide is a promising photocatalyst for its strong oxidation potential and its

moderate potential reduction due to the generation of electron - hole pairs in the valence band

(VB) and conduction (BC). The excited electrons in the BC reduce oxygen in super oxide

radical, and holes in the BV oxidize water molecules into hydroxide radicals. These radicals

are potent intermediates in the decomposition of organic molecules. In addition, the TiO2 is

physically and chemically stable and nontoxic therefore has a variety of applications such as

self-cleaning surfaces, antimicrobial and environmental purification.

In this work TiO2 thin films have been deposited on different metal substrates, using reactive

Rf sputtering technique. The structural and chemical bonding characteristics were analyzed

by X- ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). UV-Vis diffuse

reflectance spectroscopy was employed to determine the band gap energy. The

electrochemical properties of films on different metal substrates were obtained using the

electrochemical impedance spectroscopy, mott schottky and cyclic voltammetry. The results

shown a strong dependence of the metal used as substrate with the electrochemical properties

of the films.

This work was supported by SEP CONACYT (project 153245) and SIP-IPN (project

20150173)




383

[ SEM-494 ] Optical and structural properties in ZnO

nanostructures due to CTAB surfactant concentrations.

Edith bravo González 2 , Aarón Israel Diaz Cano 2 , Efraín rubio rosas 1 ,

Yosemik Arjuna León Nataret ([email protected]) 2

1 Benemerita Universidad Autonoma de Puebla, San Manuel, 72570, Mexico 2 Instituto Politecnico Nacional, UPIITA, Gustavo A. Madero, 07340, Mexico

Zinc Oxide (ZnO) nanostructures were synthesized by the Microwave Assisted

Hydrothermal method (MAH). The precursors used were Zn(CH3COO)2∙2H2O dissolved in

aqueous solution of NaOH and a concentration of 1M and stirred for 10 minutes. Were

prepared 4 solutions with 50 mL incorporating slowly 1 mL, 2 mL and 3 mL CTAB

(Cetyltrimethylammonium bromide) surfactant. One sample is not use surfactant to compare

finally results. Was used a digestion oven in two phases, first 10 minutes, 900W and 150°C,

and second 30 min, 700W and 150°C. The samples were cooled 20 min for his subsequent

extraction and centrifuged at 3600 rpm for 25 min. Finally were washed with deionized water

and dried at 60°C in air. Were used Photoluminescence (PL), UV-Vis, Raman scattering, X-

Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) characterization for the

comparative study of ZnO nanostructures. Four PL bands appear with the PL peaks at 1.54,

2.08, 2.81 and 3.08 eV due to morphology changes in function of CTAB surfactant

concentration. UV-Vis studies exhibit an increase of band gap (4.65 – 5.0 eV) due to the

enlargement in the size and density of ZnO Nanocrystals (NCs). RAMAN studies shown

bands centered in in 438 cm-1, 378 cm-1, 327 cm-1, 522 cm-1, 1075 cm-1, 150 cm-1 and

165 cm-1, shows ZnO phases corresponding to the main phonons signal in ZnO like-flower

morphology (3E2H-E2L), degrees of order-disorder network ZnO, degrees corresponding to

the contribution of energy E1 and harmonics tones of the combinations bands. It is shown

that the Raman intensity for all peaks in ZnO NCs is high twofold in comparison with those

in ZnO with low concentration of surfactant. XRD studies have shown that the thermal

annealing stimulates the ZnO oxidation and crystallization with the creation of wurtzite

crystal lattice (JCPDS 36-1451) and SEM studies show different morphologies (spherical,

wires, like-flowers & amorphous) with NCs size of 29.4 nm (diameter´s wires) and 363.6 nm

(flowers petal).




384

[ SEM-504 ] Synthesis and characterization of QDs ZnO

by colloidal method

Yosemik Arjuna León Nataret 2 , Aarón Israel Diaz Cano 2 , Efraín Rubio

Rosas 1 , Edith Bravo González ([email protected]) 2

1 Benemerita Universidad Autonoma de Puebla, San Manuel, 72570, Mexico 2 Instituto Politecnico Nacional, UPIITA, Gustavo A. Madero, 07340, Mexico

This work describes a simple process to obtain Zinc Oxide (ZnO) nanocrystals with low

dimension. The electronic, structural and compositional characteristics were discussed.

Quantum Dots Zinc Oxide (QDs ZnO) were synthetized by colloidal method using 0.05M

Zn(CH3COO)2∙2H2O in 50 ml Absolute Ethanol solution. It was stirred by 2 hrs at 700 rpm

and 80°C. A second absolute ethanol solution was prepared as previous solution at 0.1 M

LiOH∙H2O, this solutions was added to the first at the same time that it stirred at 700 rpm,

80°C for 2 hrs. The pressure increasing was controlled to sealing the flask perfectly to

conserve temperature and pressure constants. Finally it was washed in Ethanol, centrifuged

at 4000 rpm and dried for 3 hrs at 80°C. The characterization showed a hexagonal phase

(wutzite crystalline structure) according to JCPDS 36-1451. The crystal sizes were analyzed

using Scherrer equation in the (100), (002), (101) family planes using XRD information (7-

11 nm). The EDS microanalysis identified the atomic relation in function of %W (weight)

and it has 83.16 % and 16.84 % for Zn and O respectively. It confirmed the results obtained

by XRD technic. TEM measured particles with semi-spherical morphology around 7.3 nm,

witch confirmed the Nanocrystal (NC) sizes obtained in XRD processing

analysis. FTIR spectroscopy identified different vibrational modes in bands centered in 542

cm-1, 678 cm-1, 828 cm-1, 1592 cm-1 and 3326cm-1 to corresponds to stretching frequencies

for pure ZnO (NC), the charge in the microstructural features into ZnO lattice, H-O-H

assigned to small amount H2O in the QDs ZnO NCs and O-H vibrational frequencies.

PL spectroscopy showed the emission wavelength around 590 nm to correspond to red

emission, the process to generate this emission is generally considered as originating intrinsic

defects of nanocrystals such as oxygen vacancies.




385

[ SEM-510 ] Structural properties of GaN films grown

on SiC/Si(111)

Mario Cervantes Contreras ([email protected]) 1

1 Departamento de Ciencias Básicas, Unidad Profesional Interdisciplinaria de

Biotecnología - Instituto Politécnico Nacional. Av. Acueducto s/ n Col. Barrio la Laguna Ticoman, C. P. 07340 México city, México

Although some early studies of GaN deposition on SiC employed

lowtemperature buffer layers for nucleation of the GaN (in analogy with

nucleation on sapphire), more recent workers have deposited the GaN directly

on a suitably prepared SiC surface.

In this work we studied the different nucleation processes on (111) oriented Si

substrates. We prepared GaN films over SiC/Si(111) using different growth

conditions. The GaN layers were grown in a conventional molecular beam

epitaxy (MBE) system with a RF activated nitrogen plasma source (P = 400 W

and f = 2 sccm).

The GaN/SiC(Si(111) structural properties were evaluated by X – ray

diffraction Raman spectroscopy and transmission electron microscopy (TEM).

The surface morphology of the films was investigated by atomic force

microscopy (AFM).

We found that even when there is no intentional nitridation, the higher

reactivity between Si and N leads to the formation of an amorphous SiN layer

at the interface. In spite of the presence of the amorphous SiN layer, the GaN

films grew epitaxially with the hexagonal phase. In order to avoid the formation

of the amorphous SiN layer we employed a SiC buffer layer at the interface

(Figure 1). In this way we tried to reduce the reactivity between Si and N. The

results obtained by different characterizations techniques showed that the SiN

layer formation was avoided, but the obtained films presented the hexagonal

phase.




386

[ SEM-519 ] Analysis of AlGaAs:Si/GaAs

heterostructures grown as a function of the arsenic beam

equivalent pressure.

L.I. Espinosa Vega ([email protected]) 1 , S. Shimomura 2 , E.

Cruz Hernández 1 , D. Vázquez Cortes 2 , A.G. Rodríguez 1 , J.J Ortega 3 ,

Víctor Hugo Méndez ([email protected]) 1

1 Coordinación para la Innovación y la Aplicación de la Ciencia y la Tecnología

(CIACYT), Universidad Autónoma de San Luis Potosí, Universidad Autónoma de San Luis

Potosí, Álvaro Obregón 64, San Luis Potosí, S.L.P., 78000, México 2 Graduate School of Science and Engineering, Ehime University, 3 Bukyo-cho,

Matsuyama, Ehime 790-8577, Japan. 3 UAF-UAZ, Av. Preparatoria S/N, campus II, Col. Hidráulica, C.P. 98060, Zac., México.

One of the most promissory and intriguing nanostructures though which exciting

fundamental physics has arose and that have numerous applications in advanced devices are

the quantum wires (QWRs), where the charge carries are confined to freely move only along

one spatial direction. The motivation for studying the growth on (631) substrates arises from

the fact that under appropriated growth conditions uniform nanoscale step arrays can be

synthesized which for instance can be used as nanotemplates for QWRs self- assembly. In

this work, we present the analysis AlGaAs:Si/GaAs heterostructures grown on GaAs (631)

and (100) sustrates as a function of the As-cell beam equivalent pressure studied by high

resolution X-ray Diffraction (HRXRD) and Raman spectroscopy. Raman spectroscopy in

back-scattering geometry has been used for the characterization. It is observed for the AlAs-

like modes of the AlGaAs (631) films, which the ratio between transverse optical phonon

(TO) and longitudinal phonons (LO) increases with PAs, while for the (100) plane the ratio

decreases. These observations are related with HRXRD characterization of the films: high

crystalline quality for films grown on (100) as compared to the films grown on the (631)

crystallographic orientation was obtained. Additionally, by HRXRD it was found PAs-

dependent Al concentration in the AlGaAs alloys related to the Ga and Al competition for

III sites that frequently occurs in high index substrates.




387

[ SEM-540 ] Synthesis and characterization of p-doped

GaAs films grown by Molecular Beam Epitaxy

José Alberto Piedra-Lorenzana ([email protected]) 1 , Yenny

Lucero Casallas-Moreno 1 , Dagoberto Cardona 1 , Salvador Gallardo-

Hernández 1 , Gilberto Gamaliel Díaz-Monroy 1 , Carlos Alberto

Hernández-Gutiérrez 1 , Máximo López-López 1

1 Departamento de Física, CINVESTAV

During the past last decades, considerable research has been devoted to the physical

properties and the device behavior of III-V compounds semiconductors. The Development

of p-type doping techniques is needed for the design of multilayer devices. In this work, we

present the growth of p-doped GaAs films using Molecular Beam Epitaxy (MBE), the

synthesized films were (p-doped with Magnesium (Mg) and Beryllium (Be)). With the aim

of investigate the surface morphology and the hole concentration, the films were grown by

varying the Mg beam flux equivalent pressure (BEPMg) in the range of 1.5x10-9 to 3x10-8 Torr

and the growth temperature Tg in the range of 530°C to 595°C.

FESEM pictures show a clear difference between the Be-doped GaAs layers and the Mg-

doped GaAs layers. The Be-doped GaAs layers shown characteristical GaAs defects, the

density of defects decreases as the BEPBe increase, Atomic Force Microscopy (AFM) shows

higher roughness of Mg-doped GaAs than Be-doped GaAs.

We found that for high flux of Magnesium (BEPMg of 2.95x10-8 cm-3), the Magnesium

segregates to the surface and starts the formation of Magnesium Arsenide (MgAs) according

to Secondary ion mass spectrometry (SIMS) and X-ray diffraction (XRD). The measurement

of the hole concentration was made using hall effect at room temperature, the mobility for

both dopants increase as the carrier concentration decrease, the highest mobility of

128.249cm2V-1s-1 and 194cm2V-1s-1 corresponds to 3.37x1018cm-3 and 1.78x1018 cm-3 for Be-

doped GaAs and Mg-doped GaAs respectively.




388

[ SEM-544 ] Fabrication of InGaAs semiconductor

lasers for applications in technologies of the information

José Vulfrano González Fernández ([email protected]) 3 , Ismael Lara Velázquez ([email protected]) 1 , Ramón Díaz de León Zapata 2

1 2Instituto Tecnológico Nacional de México ITSLP, San Luís Potosí, SLP, 78437, México 2 2Instituto Tecnológico Nacional de México ITSLP, San Luís Potosí, SLP,78437, México 3 Instituto de Investigación en Comunicación Óptica, Universidad Autónoma de San Luis

Potosí San Luís Potosí, SLP, 78210, México

Abstract

This work presents the fabrication of optic and electronic confinement semiconductor laser

diodes with InGaAs/GaAs quantum dots matrix in the active area grown by self-assembly

technique in the Molecular Beam Epitaxy system and their morphological and optical

characterization. It seeks to tone the spectrum of photo-emission of the above mentioned

devices around the windows lower electromagnetic absorption of optical fiber

telecommunications systems.




389

[ SEM-548 ] Cleaning of GaN Surface by Chemical

Method

D. A. Flores-Cordero ([email protected]) 2 , Y. L. Casallas-

Moreno 3 , C. A. Hernández-Gutiérrez 3 , D. Cardona-Ramirez 3 , S.

Gallardo-Hernández 1 , M. López- López 3

1 Electric Engineering Department, Centro de Investigación y Estudios Avanzados del IPN,

Apartado Postal 14-740, 07360 México, D. F., México. 2 Escuela Superior de Ingeniería Química e Industrias Extractivas, ESIQIE, Apartado

postal. 07738. México D.F. 3 Physics Department, Centro de Investigación y Estudios Avanzados del IPN, Apartado

Postal 14-740, 07360 México, D.F., México.

Gallium nitride (GaN) is a semiconductor with a band gap of 3.4 eV of great technological

interest, and is very important for manufacturing optoelectronic devices such as LEDs, Laser

diodes, photodetectors. In order to improve efficiency of these devices, it is indispensable the

fabrication good ohmic contacts on GaN layers. In this work we present two methods of

chemical cleaning for GaN which removes contaminants such as a carbon and oxides that

hinder the realization of good ohmic contacts. The first method is to treat the surface of GaN

with a piranha solution (HCL:HNO3:H2O) in proportion (1:2:1). The second method is to

treat the surface with an acid solution (H2SO4:H2O2:H2O) in proportion (3:1:1) and

subsequently with an alkaline solution (NH4O:H2O2:H2O) in proportion (1:1:3). These

chemical methods in addition to reducing surface impurities such as oxides, do not alter the

surface morphology of GaN samples. The chemically cleaned samples by these two methods

were analyzed by XPS (X-ray Photoelectron Spectroscopy) and transmission line.




390

[ SEM-550 ] Device performance for InGaAsSb infrared

photodetector grown by liquid phase epitaxy

José Luis Herrera-Pérez ([email protected]) 2 , Delia María Hurtado-

Castañeda ([email protected]) 3 , José Saúl Arias-Cerón 1 , Patricia

Rodriguez-Fragoso 4 , Julio Gregorio Mendoza-Álvarez 4

1 Department of Electrical Engineering-SEES, CINVESTAV-IPN. México, D. F. 07000,

México 2 Instituto Politécnico Nacional-UPIITA, Av. IPN 2580, Col. La Laguna Ticomán, México

DF 07340 3 National Institute of Astrophysics, Optics and Electronics, Luis Enrique Erro # 1, Santa

María Tonantzintla, Puebla-México 72840 4 Physics Department, Cinvestav-IPN, A.P. 14-740, México DF 07000

We report on the characterization of the resistance area product at zero bias, R0A=dJ/dV|V=0,

for the InGaAsSb/GaSb photodiode grown by liquid phase epitaxy. The calculated R0A

values were 8.11 ohms-cm2 at T = 20 K and 2.49 ohms-cm2 at room temperature. We note

that there are essentially three regions; i) a region at low temperatures dominated by the

process associated to trap-assisted tunneling; ii) in the range between 60 K and 125 K the

generation-recombination (G-R) processes dominate; iii) at high temperatures is limited by

the G-R current and the diffusion current. The diode architecture was a back-illuminated (B-

I) structure with a ring-shaped metallic contact in the GaSb substrate face. From the

photodiode spectral response was obtained a responsivity of 0.65 A/W at a temperature of 20

K that compares well with the values reported by the more sophisticated and expensive MBE

technique.




391

[ SEM-553 ] Photoreflectance study of Mn delta-doped

GaAs/InGaAs quantum wells

G. Díaz-Monroy ([email protected]) 2 , A. Piedra-Lorenzana 2 , Y.

Casallas-Moreno 2 , S. Gallardo-Hernández 2 , D. Cardona-Ramírez 2 , C.

Hernández-Gutiérrez 2 , C. Mejía-García 1 , M. López-López 2

1 Departamento de Física, ESFM-Instituto Politécnico Nacional 2 Physics Department, Centro de Investigación y de Estudios Avanzados del IPN

In the past few years III-V semiconductor-based ferromagnetic materials such as GaAs doped

with Mn have been intensively studied. The combination of semiconducting and magnetic

properties aims to use the spin of carriers in novel spintronic devices. In order to realize these

devices, optical, electric and magnetic characterizations of spintronic materials are necessary.

In this work we studied Mn delta-doped GaAs/InGaAs quantum wells employing

photoreflectance spectroscopy (PR). The heterostructures were grown by molecular beam

epitaxy on GaAs(001) substrates. A set of samples was prepared with a constant thickness of

the InGaAs quantum well, but the thickness of the Mn-delta layer was varied: 0.4 monolayers

(ML), 0.8 ML, and 1.2 ML. We used Secondary Ion Mass Spectroscopy (SIMS) to confirm

the Mn concentration in the samples. The PR spectra show the presence of damped

oscillations at energies above the GaAs band-gap (Franz–Keldysh oscillations), which are a

clear signature of the existence of intense internal built-in electric fields in the samples. In

addition we observe two features at energies below the GaAs band-gap: at 1.41 eV which we

assign to the Mn-delta doping, and at 1.40 eV which is assigned to the InGaAs quantum well.

The variation of the PR characteristics as a function of the thickness of the Mn-delta layer is

discussed.




392

SOL-GEL (SGE)

Chairman:

L. Irais Vera Robles (UAM-Iztapalapa)

Sesión Oral

[ SGE-102 ] Adsorption and Removal of Cadmium Ions

from Simulated Wastewater Using Commercial

Hydrophilic and Hydrophobic Silica Nanoparticles; a

Comparison with Sol-Gel Particles

Susana Vargas Muñoz 1 , Martha Shaday Martínez 2 , Maykel González

Torres 1 , Sadott Pacheco Alcalá 4 , Francisco Quintanilla 2 , Antonio

Rodríguez-Canto 3 , Rogelio Rodríguez Talavera ([email protected]) 1


México, Campus Juriquilla, Apdo. Postal 0-1010, Queretaro, Qro., CP 76000, Mexico. 2 Universidad del Valle de México, Campus Queretaro, Queretaro, Mexico.

3 epartamento de Hidrobiología, DCBS, UAM-Iztapalapa, Apdo. Postal 55-534, México,

D.F. 09340, Mexico. 4 nstituto Mexicano del Petroleo, Eje Central L. Cardenas 152, Apdo. Postal 14-805, C.P.

07730, Mexico.

Adsorption and removal of cadmium ions from simulated industrial wastewater using

hydrophilic and hydrophobic commercial silica nanoparticles, are reported. These results are

compared with those obtained using sol-gel silica nanoparticles. Two types of dense

commercial pyrogenic silica nanoparticles with different chemical groups on the surface were

used to adsorb cadmium ions: Aerosil A130VS and R972. The pore absence in these particles

reduces the surface area and, consequently, the concentration of active chemical groups

appropriated for adsorption, as compared with the sol-gel particles that are highly porous;

this effect is partially compensated by the small sizes available for these commercial

particles. The concentration of cadmium ions was reduced: from 109 ppm to 0.01 ppm for

A130VS, from 138 ppm to 1.44 ppm for R972 and from 123 to 0.005 ppm for sol-gel. The

flocculation kinetics was obtained using Dynamic Light Scattering, and the amount of

adsorbed cadmium in the sediment using Atomic Absorption Spectroscopy.




393

[ SGE-210 ] Synthesis and characterization of a SiO2-

TiO2 coating by ultrasound – assisted sol-gel technique

Juan Antonio López Rubio ([email protected]) 2 , Carlos Martinez

Guzman 2 , Eduardo Arturo Elizalde Peña 2 , José de Jesús Perez Bueno 1 ,

Karen Esquivel Escalante 2

1 CIDETEQ 2 UAQ

Nowadays, atmospheric pollution is dramatically increasing the presence of

soiling on buildings due to the deposition of organic matter and other contaminants. Hence,

the development of self-cleaning coatings,using TiO2 as a photocatalyst, has received special

attention from researchers in recent years.The sol – gel synthesis was successfully

modified by incorporating ultrasound. The chemical effects of ultrasound have been

explained as the consequence of localized hot spots created during bubble collapse .For all

ultrasound assisted reactions there exists an optimus power input or amplitude at which a

specific reaction can be performed . The percentage of amplitude used in this research work

was 40 % (26kHz) the irradiation was carried out for 10 min in a 5 s pulse mode , 5 s ON

and 5s OFF mode. Tetraethylorthosilicate (TEOS) and titanium tetraisopropoxide (TTIP)

have been employed as Si and Ti sources, respectively. Ethanol (EtOH) and water were used

as solvents, while sulfuric acid assisted the catalysis of TEOS . A molar ratio

TEOS/EtOH/H2O/TTIP/H2SO4 of 1/4/4/0.1,0.2,0.5/0.0004 was used.

The water contact angle was measured and evaluated to characterize the effectiveness of

the sols in providing hydrophobic protection. The water contact angle measurements were

made using an optical tension meter under laboratory conditions, according to the sessile

drop method. It was observed that according to an increase of the molar ratio of TTIP,

hydrophobic efectiveness decreased.

The innovation of this synthesis pertains to the application of a hydrophobic transparent

nano-composite based on SiO2–TiO2 with self-cleaning properties. In addition, no toxic

catalysts have been employed in the sol–gel process and the times of reaction have been

reduced.




394

[ THF-238 ] Characterization of BST thin films for

application Resistive Random Access Memories

Juan Reséndiz Muñoz ([email protected]) 2 , José Luis Fernández

Muñoz 1 , Miguel Ángel Corona Rivera 2 , Martín Zapata Torres 1 , Alfredo

Márquez Herrera 3 , Enrique Valaguez Velázquez 4

1 CICATA-IPN 2 UASLP

3 UGT-Campus Salamanca-Irapuato 4 UPIITA-IPN

Characterization of BST thin films for application Resistive Random Access Memories

The resistive switching properties of barium strontium titanate (BST) as a thin film (1,2) are

important because their potential applications in microelectronics devices. The parameters

which govern the resistive switching behaviour have not been satisfied explain yet. The

properties of BST thin films may be best known as deposited under controlled conditions of

thermal and electrical insulation, temperature, stoichiometric composition, and deposition

time, which can be achieved with the technique RF Co-Sputtering magnetron. Thin films of

BST were deposited on quartz substrates with different values of electric power (120 watts

divided between two magnetrons) with strontium titanate (BTO) and barium titanate (STO)

targets, different temperatures (25, 374.8, 434.8, 494.8, 548.8 ºC and deposition times (since

60 until 72 minutes), gas flow Ar=18 sccm,O2=2 sccm, 30 mTorr, to achieve different

stoichiometric composition and thickness. The transmittance spectrum of thin films show

changes on its percentage depending on wavelength and temperature. We report values of Eg

and resistivity (measured with 4 probes technical), when is variated the stoichiometric

composition and deposition temperature. The Eg decreases and resistivity increases when

deposition temperature is increased. These first results are important because they ones

related to the mechanism of resistive switching behaviour when is aplicated forward and

reverse bias voltage on metal-insulator-metal MIM decives based on BST.

[1] R. Oligschlaegera, R. Waser, R. Meyer, S. Karthäuser, and R. Dittmann, Resistive

switching and data reliability of epitaxial (Ba,Sr)TiO3 thin films, APPLIED PHYSICS

LETTERS 88, 042901 (2006)

[2] Wan Shen, Regina Dittmann, Uwe Breuer, and Rainer Waser, Improved endurance

behavior of resistive switching in (Ba,Sr)TiO3 thin films with W top electrode, Appl. Phys.

Lett. 93, 222102 (2008)




395

[ SGE-248 ] Formation of Sol-Gel amorphous HfOx-

PMMA hybrid gate dielectric layer for Flexible and

transparent thin film Transistors.

Gouri Syamala Rao Mullapudi ([email protected]) 1 , Rafael

Ramirez Bon 1

1 Material Science,Cinvestav Unidad Queretaro. Libramiento Norponiente #2000, Fracc. Real de Juriquilla. C.P. 76230

For flexible thin-film transistors (TFTs), hybrid gate dielectric materials are great current

interest because of their high mechanical properties, low temperature processability, low-

cost, and operating at low voltages. In this study we report here a vacuum-free solution

processed novel organic/inorganic hybrid dielectric layer composed of HfOx-PMMA

precursor solutions. The effect of hybrid solutions are studied with and without cross linking

agent 3-Glycidoxy propyl trimethoxy silane (GPTMS). Dielectric films are readily prepared

by Spin/Dip coating process with controlled thickness (~100nm) and then followed by cured

at low temperatures (≤2000C) for compatibility of plastic substrates. The optical properties

of the hybrid films are determined by UV-vis spectroscopy and the films are optically

transparent in the visible range (400-700nm). The morphologies and microstructure of the

films depended on the amount of GPTMS in the precursor solution and were characterized

by FE-SEM. The films are homogeneous, amorphous moreover high smooth enough and

very low roughness (≤1nm) observed by AFM. The chemical composition of the films and

functional groups studied by XPS and followed by Fourier transform infrared spectroscopy

(FTIR). Additionally these hybrid amorphous films are desired for electrical and dielectric

properties such as reduced leakage current and Capacitance –Voltage properties of TFTs.




396

[ SGE-249 ] Sol-Gel deposited ZnO-CdO thin films:

Synthesis and Characterization

E. Carro-Gastélum ([email protected]) 1 , M. P. Campos-Arias 1 , G.

Alarcón-Flores 1 , M. A. Aguilar-Frutis 1 , J. A. Luna-Guzmán 1

1 INSTITUTO POLITECNICO NACIONAL CENTRO DE INVESTIGACIÓN

EN CIENCIA APLICADA Y TECNOLOGÍA AVANZADA U. Legaria Calz.

Legaria # 694, Col. Irrigación, Del. Miguel Hidalgo, C.P. 11500, México,

D.F., México

CdO and ZnO thin films are interesting Transparent Conducting Oxides that are studied

because of their electrical and optical properties. ZnO is characterized for its wide direct

energy band gap (~ 3.3 eV), high electron mobility, and high transparency in the visible range

of the electromagnetic spectrum. CdO, on the other hand, is probably the oxide that exhibits

one of the highest electrical conductivities, very close to the one shown by ITO thin films (~

103 S/cm). These characteristics make CdO and ZnO important materials for different

applications in Solar Cell technologies and in the Transparent Electronics. In this work, the

Sol-Gel technique was used to obtain ZnO-CdO thin films with a composition ranging

between ZnO and CdO. Pure CdO and ZnO thin films, and mixtures of them, were deposited

from Zinc and Cadmium acetates. The main characteristics of the synthesis and their optical

and electrical properties are presented in this work. A mixture of both oxides show a

conductivity of about 6.2 S/cm, an electronic mobility of 0.43 cm2/V-s, and a carrier

concentration in the range of 1019 cm-3. Higher and lower electronic conductivities were

obtained in pure CdO and ZnO films, respectively. The films were characterized by UV-vis

spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, and the electrical properties

were determined by Hall Effect. In resume, high quality ZnO-CdO thin films were obtained

by the Sol-Gel deposition technique.


Investigación y Posgrado del INSTITUTO POLITECNICO NACIONAL, grant # 2015-

1155, and BEIFI-IPN Program.




397

Sesión Poster

[ SGE-29 ] High Dose Thermoluminescence Dosimetry

Performance of Sol-Gel Synthesised TiO2 Phosphors

Ch. J. Salas-Juárez ([email protected]) 3 , R. Bernal 2 , C.

Cruz-Vázquez 3 , V.E. Alvarez -Montaño 3 , V.M. Castaño 1


México, Apartado Postal 1-1010, Querétaro, Querétaro 76000 México 2 Departamento de Investigación en Física, Universidad de Sonora, Apartado Postal 5-088,

Hermosillo, Sonora 83190 México 3 Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora.

Apartado Postal 130, Hermosillo, Sonora 83000 México

TiO2 is a ceramic materialwith many applications due to their different crystalline phases (

rutile, anatase and brookite [1]. It has attracted attention in several fields because its high

mechanical strength, chemical stability and ion-conducting properties [2]. Moreover, in

recent years, some research groups gained interest in the thermoluminescence features of

TiO2 concerning their potential use as thermoluminescence dosimeter. In this work, we

present the thermoluminescent characterization of Sol-Gel synthesized TiO2 phosphors

exposed to beta particle irradiation. TiO2 was prepared by alkoxide sol-gel route using

titanium tetrabutoxide as precursor, ethanol, water and ammonia as catalyst. Pellet-shaped

samples were subjected to a thermal treatment at 700 °C for 6 h in air atmosphere, and then

were exposed to radiation doses from 25 to 6400 Gy. The glow curves show a maximum

located at 171 °C, and the integrated TL is a linear function of dose in the whole dose range

studied. From the experimental results here presented, we conclude that TiO2 is a promising

material to develop high dose TL dosimeters.

References.

1.Cernea, M.; Secu, M.; Secu, C. E.; Baibarac, M.; Vasile, B. S.,. Journal of Nanoparticle

Research 2011, 13 (1), 77-85.

2.F.Gonella,G.Mattei,P.Mazzoldi,G.Battaglin,A.

Quaranta,G.DeandM.Montechi.Chem.Mal,11(1999) 814-821




398

[ SGE-177 ] Study by EDS and X-ray of ZrO2 pure and

doped with trivalent erbium, synthesized by the Sol-gel

technique

Raúl Gutiérrez Enríquez ([email protected]) 2 , Rebeca Sosa

Fonseca 2 , Alma Mireya Arrieta Castañeda 2 , Miguel Ángel García

Sánchez 1

1 Chemistry Department, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael

Atlixco 186, Vicentina, D. F. 09340, México 2 Physics Department, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael

Atlixco 186, Vicentina, D. F. 09340, México

Analysis by microscopy SEM/EDS and X-ray about the effects on spectroscopic properties

and morphological changes caused by the reduction of organic material is presented. These

were made in both two different drying process, room temperature and annealing at 500 °C

in a matrix of ZrO2 and in a ZrO2:Er3+, respectively. Additionally, these monolithic materials

were synthesized with and without acid catalysis by the Sol-gel method. The results of

microscopy SEM/EDS revealed that materials are synthesize homogeneously with a

resolution of 90μm, which provides an analysis of the solid solutions, which confirms

predominance in oxygen concentration in the matrix, against a little erbium concentrations

in ZrO2:Er3+ sample, about 2% wt, approximately. The samples of pure zirconia without

catalysis has a composition of 65% wt in oxygen and 35% wt of zirconium; where part of the

65% wt corresponds to remnants organic matter of the synthesis. On different way the sample

with catalysis has a 60/40% wt composition of oxygen and zirconium, approximately. There

is a minimum change of concentration with the use of an acid catalyst. X-ray spectroscopy

shows a structural change of amorphous to a crystalline phase, when the sample of ZrO2 is

subjected to heat treatment at 500° C. The X-ray spectra shows a tetragonal structure due to

the heat treatment; It is important emphasize that EDS of the annealing material show that

contains 35% wt of oxygen and 65% wt of zirconium content and the photoluminescence

band show a UV-shift.




399

[ SGE-229 ] Synthesis and characterization of TiO2

doped with SnO2

Karin Monserrat Alvarez Gomez ([email protected]) 1 , Joaquin

Alvarado Pulido 1 , Blanca Susana Soto Cruz 1 , Miguel Angel Hernandez

Espinosa 2

1 CIDS-BUAP 2 ICUAP-Buap

TiO2 and SnO2 nanoparticles were synthesized by sol-gel method from a precursor solution

of titanium isopropoxide tetrachloride dehydrate tin. Obtained nanoparticles were heated at

500°C for 1hr in order to crystallize them. After, TiO2 was doped with SnO2 nanoparticles

by a mixing technique, with a ratio of TiO2:SnO2 (0.1M: 0.01M). Obtained samples were

characterized through different techniques such as: X-ray diffraction (XRD), energy

backscattered spectroscopy (EDS), Raman and electron microscopy (SEM). In the case of

XRD, different phases were observed in the nanoparticles like anatase and rutile which

belongs to the TiO2 and cassiterite for SnO2. The atomic percentage ratio of the different

materials and the presence of Ti, O and Sn was obtained by EDS. Bands positions of the

samples were observed at 143, 396, 516 and 639 belonging to TiO2 through Raman

characterization. Furthermore, the morphology of the samples was obtained by SEM, where

a size less than 100nm was observed. Obtained results validate the proposed technique to

obtain TiO2 doped with SnO2.




400

[ SGE-277 ] Biomineralization of TiO2 Using a

Genetically Engineered Bacteriophage

Armin Hernández-Gordillo ([email protected]) 1 , Antonio Campero 1 , L.

Irais Vera-Robles ([email protected]) 1

1 Department of Chemistry. Universidad Autónoma Metropolitana-Iztapalapa. San Rafael

Atlixco 186, Col. Vicentina, C.P. 09340. México, D.F. Mexico.

Peptides and proteins are the most common biomolecules used by organisms in inorganic

synthesis; this process is best known as biomineralization. [1] Biomineralization can create

wonderful nano, micro and macro structures under ambient conditions. Is for this reason that

scientists are interested in mimic nature. In order to mimic the biomineralization process,

scientists have used specific peptides, which show high affinity for some material and then

they are used for its synthesis. The search of specific sequences is based on a combinatorial

technique of molecular biology named biopanning. There are several reports of sequences

with specificity to many inorganic materials such as metal nanoparticles and semiconductors.

[2]

In this way, we have chosen the peptide called H1 (HKKPSKS) [3], which has been reported

to have anatase affinity to biomineralize TiO2. Through this approach, we have obtained

anatase nanoparticles of ~5 nm in size at room temperature [4]. Thus, we are performing an

experiment in which the filamentous bacteriophage M13 -virus that infect bacteria- is being

genetic engineered in gene 8 (who express the major coat protein of virus) in order to insert

the sequence of peptide H1. On other hand, M13 phage is able to self-assembly [5] as a liquid

crystal depending on concentration, pH among others parameters. Thus, our aim is to obtain

crystalline mesoporous structures of TiO2 using engineering M13 phage as template. The

combination of knowledge from biology and chemistry can be a powerful tool for the

synthesis of novel materials and the development of new technologies through ambient

friendly techniques.

References

[1] Sarikaya, M.; Tamerler, C.; Jen, A. K.-Y.; Schulten, K.; Baneyx, F. Nature

Mater. 2003, 2, 577.

[2] Dickerson, M. B.; Sandhage, K. H.; Naik, R. R. Chem. Rev. 2008, 108, 4935.

[3] Chen, H.; Su, X.; Neoh, K.-G.; Choe, W.-S. Anal. Chem. 2006, 78, 4872.

[4] Hernández-Gordillo, A.; Hernández-Arana, A.; Campero, A.; Vera-Robles, L. I.

Langmuir 2014, 30, 4084.

[5] Chung, W.-J.; Oh, J.-W.; Kwak, K.; Lee, B. Y.; Meyer, J.; Wang, E.; Hexemer, A.;

Lee, S.-W. Nature 2011, 478, 364.




401

[ SGE-360 ] Luminescent ionogel based ionic liquid

[Carb-Bzmim] Br

Mariely Guadarrama R. ([email protected]) 1 , Antonieta García M.

([email protected]) 1 , Cesar A. Flores S. 2

1 Cerrada de Cecati s/n, Azcapotzalco, Santa Catarina, 02250 Ciudad de México, D.F. 2 Eje Central Lázaro Cárdenas Norte 152 Col. San Bartolo Atepehuacan, México D.F. C.P

07730

The ionic liquids (IL) have the advantage of being used in various applications, among which

as new materials in analytical chemistry, new solvents in electrochemical devices, green

chemistry, among others; and the ability to retain its properties to be immobilized in a matrix

of oxide acting as arranger for the formation of inorganic ionogeles, is one of the features

that attracts attention of inorganic chemistry because of how they influence the

physicochemical properties of LI in the construction of the network where the solid is

confined (Eu3+) and how involved in the phenomenon of luminescence.

[ SGE-413 ] Mn-Doped Zinc Silicate Phosphors

Synthesized by Sol-Gel Method and Solid-State Reaction:

A Comparative Study of their Optical and Structural

Properties.

Claudia Elena Rivera Enríquez ([email protected]) 1 , Ana Leticia Fernández Osorio ([email protected]) 1

1 Facultad de Estudios Superiores Cuautitlán, Campo 1. Universidad Nacional Autónoma

de México. Ave. 1o de Mayo S/N, C.P.: 54740, Cuautitlán Izcalli, México.

Mn-doped Zn2SiO4 is well-known as a green emitting phosphor due to its high luminescent

efficiency, thermal and chemical stability. This material is widely used in technological

applications such as cathode ray tubes, fluorescent lamps and plasma display panels [1]. Zinc

silicate particles have been developed industrially by solid-state reaction. This method

requires the application of a large amount of energy reaching its formation at temperatures

higher than 1300°C. Several chemical methods are being developed with the aim to develop




402

low temperature routes. Sol-gel method has had the objective to obtain fine particles

controlling particle size, shape and size distribution [2].

Solid solutions of Zn2-xMnxSiO4 (x = 0, 0.01, 0.03, 0.06, 0.09 and 0.12) powder phosphors

were successfully synthesized by solid-state reaction and sol-gel method followed by post

annealing treatments in air. X-ray powder diffraction (XRD), high resolution transmission

electron microscopy (HRTEM) and photoluminescence spectroscopy (PL) were utilized to

characterize the prepared samples.

The samples synthesized by solid-state reaction at 1400°C showed average crystallite sizes

of 80 ± 6 nm determined by XRD data. It was possible to reduce synthesis temperature of

Zn2SiO4 at 800°C using the sol-gel method achieving crystallite sizes of 42 ± 2 nm.

Crystallite size determined by Scherrer equation shows a close agreement with particle size

found by HRTEM. In both methods crystallite size increases while increasing annealing

temperature and decreases with increasing manganese concentration.

PL spectra showed a broad emission band centered at 524 nm corresponding to the 3d5

electron transitions of Mn2+ under an excitation wavelength of 250 nm. Quenching

manganese concentration are 6% and 3% mol for samples synthesized by solid-state reaction

and sol-gel method, respectively. Samples made by solid-state reaction showed higher

luminescent intensity. Reduction in luminescent intensity samples synthesized by sol-gel

method is attributed to the presence of ZnO found as a byproduct of the reaction. In both

series the emission intensity increase with increasing crystallite sizes.

[1] Y. C. Kang, H.D. Park. Applied Physics A77 (2003) 529-532.

[2] Masafumi Takesue, Hiromichi Hayashi, Richard L. Smith Jr. Progress in Crystal Growth

and Characterization of Materials 55 (2009) 98-124.




403

[ SGE-441 ] Synthesis and characterization of

nanoparticles of KNbO3 by chemicals process on acid

environment

Jesus Alfredo Hernandez Marquez ([email protected]) 2 , Manuel

Cortez Valadez 1 , Juan Francisco Hernandez Paz 2 , Jose Trinidad Elizalde

Galindo 2 , Jose Rurik Farias 2 , Pierre Giovanni Mani Gonzalez 2

1 Centro de Investigación en Física, Universidad de Sonora 2 Instituto de Ingeriería y Tecnología, Departamento de Física y Matemáticas, Universidad

Autónoma de Ciudad Juárez

Potassium niobate (KNbO3) is an important ABO3 material because of their pyroelectric,

piezoelectric, dielectric susceptibility properties and linear and no linear optical effects. The

KNbO3 nanoparticles were synthetized with chemical process that belongs to a variation of

sol-gel method using an acid environment which was obtained using citric acid. The acid

environment contributes to the reaction between K2CO3 and Nb2O5 making it control with

the KNbO3 phase, the temperature and mixing time are important variables for the reactions

too. After that, the exposition to different thermal annealing (800-1000 C) was important to

increase the superficial area and crystalline limit of grain. X-Ray diffraction (XRD) and

scanning electron microscopy (SEM) were used to ensure the quality of obtained KNbO3

nanoparticles trough structural parameters to analyze the phase and particles size for the

morphology of nanoparticles respectively.




404

[ SGE-569 ] Copper Doped Titania Prepared by Sol-Gel-

Microwave Method: Synthesis, Characterization, and

Application

Verónica De La Luz Tlapaya ([email protected]) 1 , Karina del Carmen Jiménez Córdova 2

, Ricardo Gómez Romero 1

1 Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa 2 División Académica de Ingeniería y Arquitectura, Universidad Juárez Autónoma de

Tabasco

Titanium dioxide has attracted great attention in the fields of environmental

purification, solar energy cells, photocatalysts, gas sensors, photoelectrodes and electronic

devices. In addition, their high chemical stability, environmental friendliness, easy

availability, and cost effectiveness makes TiO2 an ideal candidate as a photocatalyst [1]. The

previous research works provided some promising methods to enhance the photoactivity of

TiO2, involving metal or non-metal ions doping and co-doping. But nevertheless, the effect

of doping on the activity depends on many factors, e.g. the method of doping, and the type

and the concentration of dopant [2-3].

The synthesis of TiO2 by the sol-gel method has proven to be a very useful tool for photo-

induced molecular reactions to take place on a titanium dioxide surface [4]. There are special

variables that affect the photo-induced reactions, including particle size, phase composition,

incident light and preparation method; for instance, anatase TiO2 nanoparticles have shown

more photocatalytic activity than rutile TiO2 [5]

In this work, we prepared a TiO2 precursor by sol-gel method, and samples copper doped

TiO2 (1 and 3 % Cu) assisted by microwaves. We identified anatase phase in samples Cu

doped TiO2. These materials were probed like photocatalysts in hydrogen production as main

aim. Moreover, we observed that the incorporation of copper ions into the TiO2 structure

seems to enhance the photoactivity of the system, and with it, was improved hydrogen

production.

References [1] T. Bak, J. Nowotny, M. Rekas, C.C. Sorrell, Int. J. Hydrogen Energy 27

(2002) 991– 1022 [2] R. Jaiswal, N. Patel, D.C. Kothari, A. Miotello, Appl. Catal. B Environ.

126 (2012) 47– 54. [3] R. Jaiswal, J. Bharambe, N. Patel, A. Dashora, D.C. Kothari, A.

Miotello. Appl. Catal. B Environ. 168-169 (2015) 333–341 [4] Jang H.D., Kim S.K., Kim

S.J., J. Nanopart. Res. 3 (2001) 141 [5] Scaflani, L. Palmisano, M. Schiavello, J. Phys. Chem.

94 (1990) 829




405

THIN FILMS (THF)

Chairman:

Sandra Rodil (IIM-UNAM)

Giovanni Ramirez (Argonne National Laboratory USA)

Sesión Oral

[ THF-44 ] Yttria-stabilized Zirconia coatings on AISI

316L using the Ultrasonic Spray Pyrolysis technique by

controlling the substrate temperature and the mixture of

carrier gas

Daniel Eduardo Villalobos Correa ([email protected]) 1,2 , Jhon

Jairo Olaya Flórez ([email protected]) 1 , Ivan Romero-Fonseca 2

1 Facultad de Ingeniería, Departamento de Ingeniería Mecánica y Mecatrónica,

Universidad Nacional de Colombia 2 Vicerrectoría de Investigación, Universidad ECCI

In this research homogeneous coatings of Yttria-stabilized Zirconia on substrates of stainless

steel AISI 316L were deposited. The focus was on two important aspects: the substrate

temperature and composition of the gas mixture flow of air/nitrogen and its effect on

corrosion resistance. The corrosion resistance was evaluated by the technique of

electrochemical impedance spectroscopy (EIS) and the mechanical properties obtained by

nanoindentation. The microstructure of the coatings was characterized by scanning electron

microscopy (SEM) and confocal laser microscopy. Additionally, the crystalline structure was

determined by X-ray diffraction (XRD). The optimization of the deposition parameters has

yielded coatings of excellent quality, good adhesion and adequate corrosion resistance. More

details on the corrosion modes showed in the deposited coatings are discussed in this work.




406

[ THF-47 ] Photocatalysis in thin films elaborated by

thermal evaporation of BiOX (X = Br, Cl, I) for

degradation of Rhb in water.

Jose Luis Olivares Cortez ([email protected]) 1 , Enrique Manuel

Lopez Cuellar 1 , Azael Martinez de la Cruz 1

1 UANL-FIME

The use of organic dyes has been extensively increased in the last decades by a great variety

of industries. One of these dyes is the Rhb, it belongs to the family of the xanthans which is

used in groundwater research and dyeing cotton and silk, but recently its carcinogen potential

has been discovered. In this sense, the pollution of water with Rhb is an interesting topic, and

some semiconductor photocatalysis techniques had proven their efficacy to eliminate the

organic pollutants and in an environmentally friendly manner. BiOX compounds present a

strong absorption in the visible region, and are good candidates to be used in degradation of

Rhb. This research has the goal to elaborate thin films of BiOX (X = Cl, Br, I) by thermal

evaporation to evaluated the photocatalytic activity in degradation of Rhb and determine the

degree of mineralization of organic dye. Also is measured the activity of BiOX powders,

showing the thin films better activity than powders in degradation of this dye.




407

[ THF-113 ] Electrochemical deposition of SnS and

Sb2S3 thin film semiconductor material for photovoltaic

applications

Nini Rose Mathews 1

1 Instituto de Energia Renovables

Electrodeposition is a relatively simple and inexpensive deposition technology which can be

scaled up easily. In the present work the development of tin sulfide and antimony sulfide thin

films by electrochemical method will be discussed. SnS and Sb2S3 thin films are deposited

on SnO2:F-coated transparent conductive oxide glass substrates by pulse electrodeposition.

The potentials applied for the deposition of these semiconductor materials were determined

by cyclic voltammetry measurements from their respective baths containing tin(11) and

antimony(111) chlorides. Thiosulfate was used as the source for sulfur. The structural,

morphological and the optical characterizations of the these films were carried out using X-

ray diffraction, Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy

(XPS), and UV-VIS transmittance spectroscopy. The morphological characterizations

revealed that the films were uniform and compact. The band gap of these materials was in

the range of 1.3-1.7 eV with an absorption coefficient 105 cm-1 in the visible region. The films

were photosensitive and had good electrical properties to be used as a photovoltaic absorber

layer .

Acknowledgements:- Authors acknowledge Maria Luisa Ramon Garcia for the XRD

analysis. This work was supported by the projects: CONACYT Ciencia Basica 238869,

IN107815, CeMIE-Sol P28




408

[ THF-119 ] Synthesis of V2O5 thin films produced by

magnetron sputtering .

Dwight Acosta ([email protected]) 1 , Argelia Perez 1 , Carlos

Magaña 1 , Francisco Hernandez 1

1 Instituto de Física de la UNAM

Vanadium oxide is a material that shows a phase transition of semiconductor to metal when

is heated around of certain critical temperature. For the V2O5 compound,,this phase transition

occur at 257±5°C. The study of vanadium compounds in thin film configuration, has

received special attention in recent times because of their interesting electrochromic and

thermochromic properties and potential uses as thermal sensing, optical switches,

optoelectronic devices and energy saving devices with emphasis in the development of smart

windows 1.

In this work, vanadium pentoxide (V2O5) thin films were deposited by RF magnetron

sputtering with different deposition conditions: with and without O2, using a V2O5 target . A

power of 100 watts during 10 minutes was used to deposit vanadium oxide on corning glass

pure and coated with a conductive layer of SnO2:F (FTO) with an average sheet resistance

of 7Ω/sq . The films were deposited on substrates kept at room temperature and 400ºC

respectively. The optical and electrical properties were characterized by optical spectroscopy

in the visible and ultraviolet range and the Four Points Van der Pauw method, respectively.

Likewise, changes in resistance as a function of temperature were performed. The surface

composition and morphological properties were followed with X-ray photoelectron

spectroscopy (XPS) measurements and electron microscopy techniques. Cyclic voltammetry

experiments were performed in a potential range: E0= -2800mV to E= potential 2800 mV vs.

a platinum reference electrode with a scanning rate of 1000 mV/s. The cyclic voltammogram

exhibits the evolution of the formation of vanadium oxides until the electrochromic species

be obtained. Cycling runs, were done for 1, 10 and 60 cycles respectively and the coloration

and decoloration processes at different rates, were observed for all the cases. X-rays

diffraction patterns reveals low crystallinity mainly in samples deposited at room

temperature. For samples deposited at 400ºC , HREM micrographs confirm low crystallinity

in our samples.From SEM micrographs obtained before and after voltammetry cycling it

was observed that V2O5 films look regular and compact, with an uniform grain size

distribution. From SEM micrographs of films deposited at room temperature and 400 ºC and

after cyclic voltammetry experiments it were detected modifications in grains configuration

and surface structural properties that might be related with sample degradation and loss of

electrochromic activity as a consequence of mass and charge transport during the experiment.




409

[ THF-123 ] Influence of laser ablation plasma

parameters on the incorporation of silicon into Al-Si-N

thin films

Laura P. Rivera-Reséndiz ([email protected]) 1,2, Enrique Camps 1 ,

Stephen Muhl 2

1 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado

Postal 18-1027, México D.F. C.P. 11801, México. 2 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,

Apartado Postal 70-360, Coyoacán, México, D.F. 04510, México.

Nitride based hard films as protective coatings for cutting and wear applications have

received widespread attention in the last decades. Particularly, coatings based on Al-Si-N

were developed to improve the hardness and oxidation resistance. Different techniques

including chemical vapor deposition and magnetron sputtering have been used to grow these

films. Pulsed laser deposition is a technique that allows the deposition of ternary systems,

such as Al-Si-N, but has not been extensively used. In this study Al-Si-N thin films were

deposited using simultaneous laser ablation of two targets (Al and Si, respectively) in a

reactive atmosphere of N2, with a substrate temperature of 200 °C. The plasma parameters

(ion kinetic energy and plasma density) were studied using a Langmuir planar probe and

optical emission spectroscopy, this latter to measure the type of excited species present in the

plasma. The ion energy and plasma density of the plasma formed during the ablation of the

aluminum target was fixed at two levels of energy and for each of these two values, the

parameters of the plasma obtained during the ablation of the silicon target were varied. For

the case of high energies for both aluminum (230 eV) and silicon (80 eV) the plasma emission

at a low working pressures (4 x 10-3 Torr) was mainly dominated by the emission from N2+

(at 391.4 nm), with some smaller peaks corresponding to ionized aluminum and silicon.

When the working pressure was increased (10 x 10-3 Torr), the main emission was from

excited and neutral aluminum and the emission from ionized molecular nitrogen species was

strongly reduced. In the case when the lower value of both aluminum ion energy (105 eV)

and silicon (52 eV) was used, the main emission corresponded to excited and neutral

aluminum species which persisted for times much longer than after the laser pulse. However,

the emission from N2+ (at 391.4 nm) decayed to low intensities at working pressures of 6 x

10-3 Torr were it was usually seen that the N2+ intensity was maximum when the high

aluminum ion energies were used. In these different conditions samples were deposited and

some properties such as structure, composition, hardness and optical transmittance were

studied and are discussed in the present work.




410

[ THF-157 ] Corrosion behavior of ternary metal oxides

films obtained by magnetron sputtering

Jonatan Pérez Alvarez ([email protected]) 1 , Osmary Depablos

Rivera 1 , Roberto Mirabal Rojas 1 , Sandra E. Rodil 1

1 Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México,

Ciudad Universitaria, 04510, D.F., México

The stainless steel passivity is attributed to the formation of metal oxide film in the surface.

However, the austenitic stainless steel SS 316L have a poor corrosion resistance in solutions

containing chloride ions (Cl-), since penetration of Cl- through the passive film, increased the

corrosion rate and decrease the durability, limiting the application of this material in saline

environments. Recent studies showed that metal oxides coatings inhibit the corrosion of the

316L SS. In this work we investigated the corrosion performance of two different ternary

metal oxides, varying the composition of the Nb and Si in the Bi2O3 and in Nb2O5

respectively. The films were deposited on SS 316L substrates using a magnetron sputtering

system. Compositional characterization was done by X-ray photoelectron spectroscopy. The

structure of the films was analyzed by Raman spectroscopy and X-ray diffraction. The

electrochemical evaluation of the films were investigated from potentiodynamic polarization,

using a standard three electrode cell, employing the films as a working electrode, saturated

calomel electrode (SCE) was used as a reference electrode and platinum grid as counter

electrode, immersed in 10 wt.% NaCl; the corrosion rate was determined from Tafel

extrapolation.




411

[ THF-208 ] Study on the effects of hydrogen dilution

and B-doping on the suitability of a-SixC1-x:H thin films

for biomedical and biological applications

José Herrera-Celis ([email protected]) 2 , Claudia Reyes-Betanzo 2 , Abdu

Orduña-Díaz 1 , Adrián Itzmoyotl-Toxqui 2

1 Centro de Investigación en Biotecnología Aplicada del Instituto Politécnico Nacional, Ex-

Hacienda San Juan Molino Carretera Estatal Tecuexcomac-Tepetitla Km 1.5, C.P. 90700,

Tlaxcala-México 2 Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro #1, Santa

María Tonantzintla, C.P. 72840, Puebla-México

This work presents a study on the effects of hydrogen dilution and boron (B) doping on the

formation of Si–C and Si–H bonds during the deposition of hydrogenated amorphous silicon

carbide (a-SixC1-x:H) thin films by plasma-enhanced chemical vapor deposition. Methane

and silane were used as precursor gases, while hydrogen and diborane were the diluent and

dopant gases, respectively. The deposition parameters such as the temperature and the

methane-silane gas flow ratio were selected according to the application. Therefore,

temperatures of 150 °C and 200 °C, and methane-silane gas flow ratios of 0.70 and 0.85 were

chosen in order to obtain carbon-rich films suitable for biomedical and biological

applications. The deposition assessment was based on the results of different measurement

techniques. Fourier transform infrared spectroscopy was used to analyze the formation of

bonds. The effects of hydrogen dilution and B-doping on optical and electrical properties of

the films were studied using UV-visible spectroscopy and electrical dark conductivity

measurements. The surface morphology analysis was made by atomic force microscopy. The

results show that, under the proposed deposition parameters, the hydrogen dilution and the

B-doping affect mainly the formation of Si–H bonds, whereas the formation of Si–C bonds

is governed by the methane-silane gas flow ratio. Furthermore, both the hydrogen dilution

and the B-doping decrease the optical band gap and increase the conductivity of the films.

Regarding the degree of disorder, the hydrogen dilution decreases it, while the B-doping

increases it. Carbon-rich B-doped a-SixC1-x:H thin films with a root mean square roughness

of about 1 nm, a conductivity of the order of 10-6 S/cm and a high density of Si–C bonds

were obtained. These findings are important to incorporate the material in implants,

implantable devices or biosensors.




412

[ THF-264 ] The surface plasmons resonances in the

visible range of the silver-tin dioxide thin films system

Narcizo Muñoz-Aguirre ([email protected]) 1 , Luis Felipe Rodríguez Llamas

1 , Omar Rosales Altamirano 1 , Lilia Martinez Perez 2



Catarina. Del. Azcapotzalco, CP. 02250, México, D.F. México 2 Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas del Instituto

Politécnico Nacional, Av. IPN No. 2580, Col. Barrio La Laguna Ticomán, C.P. 07340,

México D.F. México.

The Surface Plasmons Resonances of silver-tin dioxide (Ag-SnO2) thin films system as a

function of the wavelength of the incident light beam are determined. In order to determine

the Plasmons Resonances in the visible spectrum range, calculations and plots of the

reflectance spectra as function of the wavelength, at fix angle of incidence, were carried out

using academic Maple software. In the calculations, the dielectric function of the SnO2 thin

films was obtained fitting the Sellmeier model to the experimental data reported by Shamala

et. al. , and the dielectric function of the silver films was determined using the Drude´s

formula. The results showed that bilayer systems with thicknesses in the order of 35 nm and

10 nm of Silver and Tin Dioxide films, respectively, shown Resonances in the 375-800 nm

range. Experimental measurements for the Ag-SnO2 system confirmed such theoretical

results. The purpose of obtaining and tuning the resonances in a specific position is to work

in the amplitude mode of operation using a monochromatic beam. Furthermore, thinking

about future gas sensing applications, changes of the order of 10-4 in the refractive index of

the air were theoretically studied resulting in shifts of the resonance positions of some

nanometers, which can be measured by this SPR method.

1.- N. Muñoz-Aguirre, C. A. Andrade-Arreguin, C. Ávila-Salazar, P. Tamayo-Meza and L.

Martínez Pérez. Optical characterization of low density polyethylene thin films by Means of

Surface Plasmon Resonance. Optics of Surfaces and Interfaces 9 (OSI9), Septiembre 19-23

Akumal, México, 2011.

2.- N. Muñoz Aguirre, L. Martínez Pérez, J. A. Colin, E. Buenrostro González, Sensors 7(9),

1954 (2007).

Acknowledgements. Work partially supported by Instituto Politécnico Nacional from

México with the project number SIP-20151005. Authors also would like to acknowledge the

technical assistance of Ing. Ana Berta Soto and QFB. Marcela Guerrero both from the

Physics Department of CINVESTAV-IPN.




413

[ THF-308 ] The Seebeck Effect for Key Thin-Film

Thermoelectric Materials as a Function of Thickness

Horacio Estrada ([email protected]) 2 , Francisco J. Hernández-Cuevas

1 , Miguel A. Aleman-Arce 1

1 CNMN - Instituto Politécnico Nacional, Mexico, DF 2 Centro Nacional de Metrología, Queretaro, QRO

ABSTRACT

Results of a detailed study of the Seebeck effect for thin films of pure bismuth and antimony,

with respect to platinum thin films will be presented. The characterization of the

thermoelectric properties of thin films is aimed at identifying the optimum films for the

implementation of various devices based on this effect including thermoelectric converters

for metrology applications, high sensitivity temperature and biosensors, and thermoelectric

power generators. Thin films deposited by DC-magnetron sputtering on polyimide films are

investigated for their thermoelectric power with respect to platinum. The value of Seebeck

coefficients is established using a simple but yet quite accurate experimental setup that

considerably reduces most possible uncertainties. It will be shown that the dependence of the

Seebeck coefficient with the film thickness for bismuth is opposite to that for antimony, and

these variations are correlated with the films’ crystallographic structure, using XRD methods.

For the thickness-range that has been thus far investigated, the values for thermoelectric

power of Bi vary from -50 to -90µV/oC, higher than its bulk-value of -70µV/oC that has been

long reported in the literature, while the ones for Sb vary from +23 to +28µV/oC, which

concur with some reported data for films deposited by other methods, but lower that the bulk-

value of about +40µV/oC. The results of this study will be important to define the films for

Bi-Sb alloys and other to optimize the Seebeck coefficient most applicable to the devices

under consideration.




414

[ THF-328 ] Studies on optical, morphological,

structural and electrical properties of CdS : Cu thin solid

films that were synthesized by using chemical wet

technique.

Fernando Sánchez 4 , Gelacio Atondo 2 , Cristo Yee 2 , Oscar Velarde 2 ,

Miguel Aguilar-Frutis 1 , Manuel García-Hipólito 3 , Francisco Ramos-Brito


1 CICATA Legaria - Instituto Politécnico Nacional 2 Facultad de Ciencias Físico Matemáticas - UAS

3 Instituto de Investigaciones en Materiales - UNAM 4 Student in Facultad de Ciencias Físico Matemáticas - UAS

Thin solid films of ZnO were synthesized by employing chemical wet technique. Films were

obtained as function of different parameters: precursors, deposition time and annealing

temperature. Transmittance, Resistivity, Photo and Cathodoluminescence (PL, CL) at room

temperature, XRD, HR-SEM, HR-TEM, and AFM studies were done. The thicknesses of the

films were measured by using a surface profiler KLA-Tencor/P 15 obtaining an average

thickness of 160 nm for all films. The surface of undoped films was conformed by splinter

shaped nanoparticles with width distribution functions centered at around 35 nm and FWHM

= 0.603 nm. The crystalline phase of films was cubic and invariant under changes in

deposition time or precursors. All samples resulted with a = 5.82 A lattice constant,

crystalline grain size of around 6 nm and preferred (111) orientation. The presence of

monoclinic CdSO4 • H2O in undoped films was investigated. HR-TEM and XRD studies

were in good agreement. HR-TEM shows a film surface conformed by regularly-spaced

entities asterisk shaped of around 35 nm size composed by the superposition of several nano-

crystals with dimensions lower than 10 nm. The films presented an energy gap of around 2.4

eV that move slightly with changes in deposition time and precursors. The PL and CL

emission spectra present the free exciton emission and reveal the presence of structural

defects. Defects were identified. The resistivity achieved was of 5.822 x 10 -5 ohm/cm.




415

INVITED TALK

[ THF-344 ] Pushing the performance limits of electrical

contact materials - connecting nano to macro

Nicolas Argibay ([email protected]) 1 , Michael Chandross 1 , Blythe

Clark 1 , Michael Dugger 1 , Somuri Prasad 1

1 Sandia National Laboratories

From nano- and micro-electromechanical systems (NEMS/MEMS) to wind turbines and

satellites, the desire to engineer electrical contacts with increasingly greater efficiency and

reliability in increasingly more aggressive and demanding operating environments continues

to provide ample motivation for both applied and fundamental cutting-edge, multi-scale and

multi-disciplinary materials research. In this presentation we share new insights based on

experimental and atomistic simulations on the fundamental mechanisms of wear and friction

of metal contacts, the results of recent efforts to develop metal-matrix nanocomposite and

high-temperature nanostructured binary metal alloy thin films, and end with a discussion of

ongoing research efforts aimed at overcoming longstanding technical obstacles in the wind

power and electronics industries.




416

[ THF-429 ] Temperature Dependence of Resistive

Switching Memories based in Ultra-Thin Hafnium Oxide

Dielectrics

Rene Valderrama ([email protected]) 1 , Joel Molina 1

1 Electronics Department, National Institute of Astrophysics, Optics and electronics

(INAOE), Tonantzintla, Puebla, 72000, Mexico.

Resistance Random Access Memories (ReRAM) based in hafnium oxide and having

different concentrations of oxygen vacancies are present in this work. They are a candidate

for the next-generation of nonvolatile memory technology, because of their suitability against

scaling down, low power consumption and fast switching speed. The structure of these

ReRAM memories is simple just like a capacitor consisting of two metal electrodes and an

insulator (MIM structure). For fabrication of these MIM structures, N-type Silicon wafers

(100) with resistivity of 5-10 Ω•cm were used as substrate which were cleaned with standard

procedures. Three different ReRAM devices were fabricated using stoichiometric HfO2, non-

stoichiometric HfOx and HfOx-HfO2 as mixed layer, all deposited at 250°C by Atomic Layer

Deposition technique using different exposure times to H2O precursor in order to promote

oxygen-rich, oxygen-deficient and a stack layers, and the other precursor being TDMAH.

Tungsten and aluminum were deposited by E-beam Evaporation under ultra-high vacuum

conditions and they were used as bottom and top electrodes of the MIM structure

respectively. After MIM fabrication a lithography process was applied to all samples in order

to define the gate area which is 64e-6 cm2. It was reported that the resistance switching is due

to the formation/dissolution of filaments inside the dielectric film, these filaments are created

for the movement of oxygen vacancies which are repaired by Joule heating effect of the

current through the filaments. Based on this phenomenon, the influence of test temperature

on ReRAM memories was studied from I-V measurements, where different conduction

mechanisms were fitted to experimental results in order to highlight physical parameters

which can help to understand better the resistance switching of these memory devices and

then improve their performance characteristics.




417

[ THF-462 ] Vanadium oxide compounded with silver

prepared by pulsed laser deposition using a two parallel

plasmas configuration

Fernando Gonzalez Zavala ([email protected]) 5 , Luis Escobar

Alarcon 2 , Dora Alicia Solis Casados 1 , Emmanuel Haro Poniatowski 3 ,

Rafael Basurto 4

1 Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM 2 Departamento de Física, Instituto Nacional de Investigaciones Nucleares

3 Departamento de Física. Universidad Autónoma Metropolitana Iztapalapa 4 Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares

5 Doctorado en Ciencia de Materiales. Facultad de Química. UAEMex

Thin films of vanadium oxide compounded with silver were prepared by pulsed laser

deposition using a two parallel plasmas configuration. Deposits on glass and silicon

substrates using a Nd:YAG (1064nm) laser were obtained. High purity vanadium and silver

targets were ablated in vacuum at working pressures close to 4x10-6mbar. During

experiments the plasma parameters, mean ion kinetic energy and plasma density, of

vanadium remain approximately constant while the plasma parameters of silver were varied

in order to obtain different silver content in the deposited thin film. Afterwards, the thin films

were subjected to thermal treatment at 450°C in order to obtain crystalline oxides. The

obtained materials were characterized by Raman spectroscopy showing that the thin films

were composed by mixtures of vanadium oxides, silver vanadate, and silver oxides in

different proportions. XPS confirmed the existence of mixtures of V2O5, V2O3, VO2 and

AgVO3, as well as the presence of AgO and AgO2 for films prepared at higher silver plasma

densities. EDS results showed silver contents ranging from 6.2 to 17.4 at. % at corresponding

to the lowest and the highest silver plasma density. Surface morphology was observed by

SEM, characteristic vanadium pentoxide acicular structures were observed at low Ag

contents; the length of such structures increases as the silver plasma density employed during

the deposition experiment was increased.




418

[ THF-508 ] Surface processing of carbon fiber

composites for the effective adhesion of primary

structures in aeronautics applications

Víctor Hugo Martínez-Landeros ([email protected]) 2 , Sandra Yesenia

Vargas-Islas 2 , Serafín Barrera 1 , Khassan Mourtazov 1 , Jorge Herrera-

Ordóñez 2 , Gerardo Trápaga-Martínez 2 , Rafael Ramírez-Bon 2

1 Bombardier Aerospace México 2 CINVESTAV - Unidad Queretaro

Adhesive bonding techniques to join advanced composite materials for critical structures of

the aircraft parts (critical load carrying component) need to be investigated to attain the

vanguard of technology in design and manufacturing of aircrafts. It consists by preparing the

surface of the composites based on carbon fiber, for efficient adhesion in primary structures

and selecting the most appropriate methodology to measure the quality of surface preparation

of such composites prior to bonding with other parties. This development results from tests

of the composite materials, adhesives and mechanical quality tests under various bonding

surface preparation of the composites. The analysis was performed by means of several

spectroscopic and microscopic techniques, such as XPS, FTIR, SEM, AFM, etc., and a

contact angle measurement technique which provides a direct, fast and easy measurement of

the surface energy of the fiber composites. The ASTM D 5528-01, reapproved 2007 norm

was employed for the analysis of the mechanical testing of the adhesively bonded carbon

fiber composites. The mechanics of the linear elastic fracture is considered a tool for the

failure of the laminate in composite materials with cracks or cuts in the plane, due to the

presence of damaged zones in the tip of the crack; which is therefore applied to the study of

delamination or fracture toughness.

Keywords: Adhesive bonding, surface processing, contact angle, mechanical tests.




419

[ THF-530 ] Deposition and Characterization of CuS by

Successive Ionic Layer Absorption and Reaction

Obed Yamín Ramírez-Esquivel ([email protected]) 1 , Raquel

Garza-Hernández 1 , Eduardo Martínez-Guerra 1 , Francisco Servando

Aguirre-Tostado ([email protected]) 1

1 CIMAV-Monterrey, Alianza Norte 202, Parque PIIT, Apodaca, N.L., México 66628.

The deposition of semiconductor materials for photovoltaics applications by solution

methods is attractive because it implies low processing temperatures, low cost and large area.

However the elucidation of the process reaction paths is of tremendous importance in order

to understand how to control the physical and chemical characteristics of the deposited films.

Successive Ionic Layer Absorption and Reaction (SILAR) is a solution-based technique that

allows for the control of composition and thickness by simply manipulating the solution

composition, ion concentration and solution temperature. The technique consists of

successive dipping of a substrate on separate cation and anion precursor solutions with

intermediate DIW rinsing steps. Cu2S is a p-type II-V semiconductor with a direct band gap

of 1.2eV employed in solar cells as the active layer or as a precursor for ternary or quaternary

systems such as CIGS, CIS and CTS. Upon thermal annealing in vacuum CuS decomposes

into Cu2S and S2 through the following reaction 4CuS = 2Cu2S + S2. In this work CuS thin

films were deposited by SILAR on glass substrates from CuSO4, Na2S and Thiourea

precursors in aqueous solutions. The deposition speed depended on the concentration of

NH4OH of the cationic solution and type of anionic precursor as well as on its concentration.

X-ray photoelectron spectroscopy analysis was used to understand the nucleation and initial

stages of CuS formation during the first deposition cycles. The dependence of the optical

characteristics, morphology, grain structure, chemical composition and electrical

characteristics as function of the deposition conditions will be discussed.




420

Sesión Poster

[ THF-7 ] Fabrication of hydrophobic films from ps with

contact angle above 90º

Rafael Catarino ([email protected]) 1 , Elías Pérez 1

1 IF-UASLP

This work is aimed to the fabrication of polymeric rough surfaces from the mixture of two

immiscible polymers: Polystyrene (PS) and Poly-(Butyl Methacrylate) (PBMA), both

dissolved in a common solvent: Tetrahydrofuran (THF). The interest of this work is to

generate hydrophobic and super hydrophobic films from structured surfaces (nano and

micro) in order to shape these two polymers when the solvent suddenly evaporates. All

samples were submitted to the following analysis: Infrared Spectroscopy (FTIR) for the

evolution of surface chemical species, Atomic Force Microscopy (AFM) for supervising the

topography of the films and, Contact Angle (CA) to modulate the water wettability extension

on the films and the evolution of this parameter for each treatment.

[ THF-25 ] Chemical bath deposition of zno thin films

and their application in field effect transistors

María del Carmen Camacho Alcántar

([email protected]) 3 , Rodolfo Bernal 2 , Dainet Berman

Mendoza 2 , Catalina Cruz Vázquez 3 , Víctor Manuel Castaño 1


México, Apartado Postal 1-1010, Querétaro, Querétaro 76000 México 2 Departamento de Investigación en Física, Universidad de Sonora, Apartado Postal 5-088,

Hermosillo, Sonora 83190 México 3 Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora,

Apartado Postal 130, Hermosillo, Sonora 83000 México

ZnO films have been studied as the active channel material in thin-film transistors because it

is an n-type semiconducting material with a wide band gap of 3.3 eV, chemically inert and it

exhibits thermal stability. Moreover, it can be growth along certain crystalline planes if

deposited on the suitable substrate.[1]




421

In this work, we report the fabrication of ZnO film– based Metal Oxide Semiconductor Field

Effect Transistors (MOSFET). The used ZnO films were synthesized by a chemical bath

deposition method, and their electrical properties measured after being subjected to different

thermal treatments. The fabricated transistors have a structure consisting of a low resistivity

Si substrate, a SiO2 thin layer as the insulator gate, the synthesized ZnO thin film as the active

channel, and two Al contacts as source and drain terminals; by the backside of the silicon

wafer a thin Al layer was deposited to generate the gate electrode. With this structure,

saturation currents dependent on the thermal annealing of the ZnO films are observed in the

I-V curves.

[1] H. C. Cheng, C. F. Chen and C. C. Lee, Thin Solid Films, Vol. 498, No. 1-2, 2006, pp.

142-145.

[ THF-46 ] Scattering of Gaussian electromagnetic beams

by a stack of graphene layers

Juan Sumaya Martínez ([email protected]) 1 , Raúl Salazar

Hernández ([email protected]) 1

1 Physics Dept., Universidad Autonoma del Estado de Mexico. Instituto Literario 100,

Col.Centro. Toluca, Edo. Mex.

The interaction of Gaussian electromagnetic beams with single-layer graphene and a stack

of parallel graphene sheets at arbitrary angles of incidence is studied. It is found that the

scattered energy is strongly dependent on the polarization (TM or TE- polarization), on the

angle of incidence, on the thickness hi of layers and on the beam diameter L. Finally we show

that a periodic stack of planar graphene layers has features similar to those of an one-

dimensional photonic crystal, with gaps at certain frequencies.




422

[ THF-48 ] Single and twofold SiOx films deposited by

HFCVD: Hydrogen flow and annealing effect on the

photoluminescent properties

Diana Elizabeth Vázquez Valerdi ([email protected]) 1 , Jose Alberto

Luna López 1 , Godofredo García Salgado 1 , Jesús Carrillo López 1 , Alfredo

Benítez Lara 1

1 IC-CIDS Benemérita Universidad Autónoma de Puebla, Ed. 103 C o D, Col. San Manuel,

C.P. 72570 Puebla, Pue., México.

In this work, the hydrogen flow and annealing effect on the photoluminescent properties of

the single and twofold non-stoichiometric silicon oxide (SiOx) films is reported. The single

and twofold SiOx films are obtained by hot filament chemical vapor deposition technique in

a temperature range from 795 to 829 °C at two hydrogen flows, 25 and 75 sccm. The single

and twofold SiOx films as-grown and annealed are characterized by Fourier transform

infrared spectroscopy and photoluminiscence. FTIR reveals, so that, the both films

composition changes with the hydrogen flow. In general FTIR spectra show vibrational bands

related to the presence of hydrogen in the both films as-grown. This band disappears after

thermal annealing. The single SiOx films exhibit PL intensity bigger than the twofold SiOx

films. The single SiOx films as-grown exhibit PL spectra with two main peaks at 700 and 750

nm. These bands are more intense as the grown temperature is decreased as well as the

hydrogen flow decreased. When the single SiOx films are thermally annealed the PL intensity

is more intense as the grown temperature is increased as well as the hydrogen flow increased,

at the same time that the presence of hydrogen disappears. The twofold SiOx films as-grown

exhibit PL spectra with a main peak at 750 nm. The film deposited at 795°C-25sccm / 795°C-

25sccm has the biggest PL intensity. The PL intensity increased after the twofold SiOx films

are thermally annealed. Also the spectra width increased, exhibiting a broad spectrum from

600 at 875 nm. These results lead to good possibilities for proposed novel applications in

optoelectronics devices.




423

[ THF-82 ] Next generation environment protection

sensor

Vinoth Kumar Jayaraman ([email protected]) 1 , Yasuhiro Matsumoto

1 , Maria de la luz Olvera Amador 1

1 Department of Electrical Engineering, CINVESTAV-IPN, Mexico City, Mexico

Propane is a colorless, odorless, flammable and non-toxic gas, which is one of the major

hydrocarbon in LPG (Liquefied Petroleum Gas) used in day to day life. In addition, propane

is an important source of energy. When propane is used as a fuel in vehicles, causes less

pollution than other petroleum products. It is predicted that there will be propane gas stations

than other petroleum products. Therefore, it is mandatory to design a gas sensor to detect

propane leaks to ensure safety for the environment. In this work, we are reporting results

about sputtered zinc oxide (ZnO) thin films for manufacturing propane gas sensors. Zinc

oxide thin films were deposited by the radio frequency (RF) magnetron sputtering technique,

at different RF on glass substrates. Structural, morphological, and gas sensing properties of

the thin films were studied in detail. Structural analysis of all deposited films was performed

by X-Ray diffraction (XRD) to confirm the wurtzite hexagonal ZnO phase, the preferred

growth orientations, and the crystallite size. Scanning Electron Microscopy (SEM) technique

was used for analyzing the surface morphological changes as a function of the RF power.

Variations in RF power resulted in change in the grain size and the thickness of the films at

similar deposition conditions. Gas sensing performance was tested in a propane gas

atmosphere at different operation temperatures, and different propane concentrations.

Sensitivity of sputtered ZnO thin films were in three orders of magnitude even at low

concentration of gas.




424

[ THF-83 ] A simple and cost-effective zinc oxide thin

film sensor for propane gas detection

Vinoth Kumar Jayaraman ([email protected]) 1 , Arturo Maldonado

Alvarez 1 , Maria de la luz Olvera Amador 1

1 Department of Electrical Engineering, CINVESTAV-IPN, Mexico City, Mexico

In this work, we have reported a cost-effective thin film of zinc oxide (ZnO) sensor for

propane gas detection. ZnO thin films were deposited on soda lime glass by ultrasonic spray

pyrolysis using zinc acetylacetonate as a precursor in the starting solution. Thin film

deposition was carried out at 450°C, by varying the water content in the spraying (starting)

solution. Structural, morphological, and gas sensing properties were studied in detail.

Variations in the water content resulted change in crystallinity, geometries, and gas

sensitivity. ZnO thin film exhibited maximum sensitivity ~7, when measured at 100°C.

[ THF-84 ] Simulation of a device for laminar flow

generation in a SPU system

Jorge Carmen Flores Juan ([email protected]) 2 , Evaristo Isac

Velázquez Cruz 2 , Guillermo Juárez López 2 , Rafael Martínez Martínez 2 ,

Julián Javier Carmona Rodríguez 2 , Edgardo Yescas Mendoza 2 , Ciro

Falcony 1

1 Centro de Investigación y de Estudios Avanzados de lIPN, Departamento de Física,

Av.IPN 2508, Col.San Pedro Zacatenco,C.P. 07360 México D.F 2 Universidad Tecnológica de la Mixteca, Carr. A Acatlima km 2.5, Huajuapan de León,

Oaxaca. CP 69000.

Ultrasonic Spray Pyrolysis (SPU) system produced a droplet size that is direct function of

two parameters. The first parameter is the vibration frequency of piezoelectric, since the

higher the frequency of vibration the drop size generated is smallest and the second

parameter, are the conditions in the which the aerosol is generated. A laminar flow is

associated with an order along the path followed by the droplets composing the spray, that

is a turbulent flow is prevented. So, in this work, a theoretical comparative study is performed

of the influence of the nozzle geometry and the volumetric flow of carrier gas to obtain a

laminar flow of aerosol in a SPU system. The study was performed with the SolidWorks




425

2013 software. To simulate four different nozzle geometries were used, the best results were

obtained with a geometric shape of circular type with four boosters of air distributed evenly

around a circular section where the aerosol emerges. To generate the laminar flow, an air

flow was used at a rate of 10 and 15 LPM, the first present with minus turbulence to the

nozzle exit.

[ THF-90 ] Wear performance of expanded austenite

obtained by high temperature pulsed plasma nitriding of

austenitic stainless steel.

J.C. Díaz-Guillén ([email protected]) 3 , J.C. Díaz-Guillén 1 , E.E.

Granda-Gutiérrez 3 , J.L. Acevedo-Dávila 3 , R. Muñoz-Arroyo 3 , J.A. Díaz-

Guillén 2 , A. Garza-Gómez 3

1 Dirección de Cátedras. Consejo Nacional de Ciencia y Tecnología. México D.F. 2 División de Estudios de Posgrado e Investigación. Instituto Tecnológico de Saltillo.

Saltillo México 3 Gerencia de Desarrollo Tecnológico. Corporación Mexicana de Investigación en

Materiales S.A. de C.V. Saltillo México

Expanded austenite (S) has been identified as crystalline phase with remarkable properties

when it is used for wear or abrasion applications. This phase is produced through introduction

of atomic nitrogen on the surface of austenitic stainless steel by the use of plasma assisted

processes as ion nitriding. The good properties of this solid solution have been attributed to

both, the surface structural strain phenomenon, and the generation of high compressive

stresses promoted by nitrogen introduction in the octahedral interstitial sites of austenite. It

is also known that nitriding treatment at temperatures above 440°C promotes the detrimental

of corrosion properties as a consequence of chromium nitrides precipitation. In this sense, in

order to avoid decreasing in corrosion properties, typical treatment is carried out for periods

up to 6 h. In the present work, pulsed plasma nitriding at high temperature and short time

was carried out on 316L austenitic stainless steel. A free chromium nitride layer of expanded

austenite with 8 mm in thickness was identified on the surface of 316L samples through X-

ray Diffraction and Scanning Electron Microscopy. Pin on disk wear test, performed using

52100 steel balls as a static friction partner, shows the significant drop of the friction

coefficient of expanded austenite in respect to untreated sample and the consequent decrease

in the wear volume. Obtained results promise an important decrease in the nitriding process

duration which can result in a considerable energy saving for this technological process.




426

[ THF-105 ] Europium decorated graphene films

Veronica Janette Cedeño Garcidueñas ([email protected]) 4 , Ricardo

Rangel Segura 4 , Pascual Bartolo Pérez 5 , Luis Mariano Hernández

Ramírez 3 , Rafael García Gutiérrez 2 , Donald Homero Galván Martínez 1

1 Departamento de Fisicoquímica de Materiales, CNYN- UNAM Ensenada. 2 Departamento de Investigación en Física, Universidad de Sonora

3 División de Estudios de Posgrado, Facultad de Físico-Matemáticas, Universidad

Michoacana de San Nicolás de Hidalgo 4 División de Estudios de Posgrado, Facultad de Ingeniería Química, Universidad

Michoacana de San Nicolás de Hidalgo 5 División de Física Aplicada, CINVESTAV-IPN Unidad Mérida

The room temperature mobility, transparency, thermal conductivity and high Young’s

modulus properties of graphene have attracted the attention in many fields and make

graphene a promising candidate for applications in electronic, energy storage devices and

sensors [1-3]. Graphene is a bidimensional material where its carbon atoms bonded together

in a hexagonal lattice. Since graphene was discovered, many synthesis routes have been

studied to produce large-area graphene. Chemical vapor deposition is the most suitable

method to prepare easily transferable films [4]. Despite of their excellent properties, graphene

may be doped in order to promote changes on their electronic, chemical and magnetic

properties for application in electronic devices [5].

The synthesis of graphene begins with the choice of copper foil due to low solubility of

carbon and a gaseous source of carbon such methane. Copper films were deposited by spin

plasma coating, and further introduced in a 1 in diameter tube furnace, under an Ar/H2 gas

mixture at atmospheric pressure. After annealing the Si/copper substrate for 10 min, graphene

was growth at 1000°C using a methane flow, for 30 min. The films were decorated with

europium at 800°C under inert atmosphere (Ar) and europium nitrate pentahydrate being

used as precursor.

Samples were characterized by AFM (Atomic Force Microscopy), RAMAN and TEM

(Transmission Electronic Microscopy). The characterization shows regular deposition of

graphene and a uniform europium film.

[1] Hu B., Ago H., Ito Y., Kawahara K., Tsuji M., Magome E., Sumitani K., Mizuta N., Ikeda

K. and Mizuno S. 2012. Epitaxial growth of large- area single –layer graphene over Cu

(111)/sapphire by atmospheric pressure CVD. Carbon, 50, 57-55.

[2] Bernard L.S., Spina M., Jacimovic J., Ribic P.R., Walter A., Orbeli D.Y., Horvath E.,

Forró L. and Magrez A. 2014. Functionalized graphene grown by oxidative dehydrogenation

chemistry. Carbon, 71, 11-19.




427

[3] Yao Y. and Wong Ch. 2012. Monolayer graphene growth using additional etching process

in atmospheric pressure chemical vapor deposition. Carbon, 50, 5203-5209.

[4] Bhaviripudi S., Jia X., Dresselhaus M., Kong J. 2010. Role of kinetics factorsin chemical

vapor deposition synthesis of uniform large area graphene using copper catalyst. Nanoletters,

10, 4128-4133.

[5] Ruitao Lv. and Terrones M. 2012. Towards new graphene materials: doped graphene

sheets and nanoribbons. Materials Letters, 78, 209-218.

[ THF-118 ] Structural, optical, electrical properties of

spray pyrolized Mo:WO3 and TiWO3: thin films

Dwight Acosta ([email protected]) 1 , Carlos Magaña 1 , Francisco

Hernández 1

1 Instituto de Física de la UNAM

The influence of molibdenum and titanium doping on WO3 thin films produced with a

low cost pneumatic spray pyrolysis equipment, in the structural, electrical, optical and

electrochromic properties has been investigated .Tungsten trioxide in thin film configuration

is a very interesting material with optical, electrical and electrochromic properties which

make it suitable for practical and advanced technological applications.The use of

electrochromic and thermocromic materials for energy saving purposes is a subject of

intensive research around the world. Electrochromic behavior of tungsten trioxide thin films

have been studied extensively for last 30 years due to their potential applications in display

devices, rear view windows and smart windows for energy saving purposes.Mo:WO3 and

Ti:WO3: thin films have been deposited on FTO/Glass substrates by thepulsed chemical

spray technique at a substrate tempertature of Ts = 450°C. The effects of doping

concentration in the starting solution on structural, optical electrical and electrochromical

properties were followed by the XRD, SEM, HREM, AFM, van der Pauw and cyclic

voltammetry experimental techniques. The Mo:WO3 and Ti:WO3 thin films present for all

the cases, a regular and compact surface but grain size distribution and morphology show

differences as the metals concentration is increased. There is a noticeable improving in

conductivity and carrier density when the Mo and Ti concentrations are increased in the

starting solution. The electrochromic properties of Mo:WO3 and Ti:WO3: thin films are re-

visited and correlated when possible with the parameters used during the synthesis . The

electrochromic phenomena was induced in an electrochemical cell using the Cyclic

Voltammetry technique. The charge diffusion coeficients during the

electrochromic coloration associated in turn with cathodic and anodic peaks, present

different values for equivalent Mo and Ti atomic concentration in the starting solution

used for the films deposition.




428

[ THF-140 ] Pulsed laser deposition of zinc vanadium

oxides from a ZnV2O6 target

J.G. Quiñones-Galván 3 , R. Lozada-Morales 6 , Enrique Camps 5 , Y.A.

González-Rivera 6 , S. Jiménez-Sandoval 2 , E. Campos-González 4 , M. Zapata-Torres 1 , A. Pérez-Centeno 3 , M.A. Santana-Aranda 3

1 CICATA-IPN, Unidad Legaria, Mexico D.F.11500, Mexico 2 Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional,

Unidad Querétaro, Apartado Postal 1-798 Querétaro, Qro, 76001, México 3 Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías,

Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, Guadalajara,

Jalisco, Mexico, C.P. 44430 4 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, P.O. Box 14-740, México D. F., 07360, México 5 Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado

postal 18-1027, México D.F., C.P. 11801 6 Facultad de Ciencias Físico-Matemáticas, Postgrado en Física Aplicada, Benemérita

Universidad Autónoma de Puebla, Av. 14 sur y Av. San Claudio, Col. San Manuel, Puebla,

Mexico

Thin films of different zinc vanadium oxide compounds were grown on glass substrates at

room temperature by means of the pulsed laser deposition technique. A polycrystalline

ZnV2O6 target was used for the ablation process. The target was prepared by the melt

quenching method at a temperature of 1000°C using a starting mixture of ZnO and V2O5.

The films were annealed at 500 °C in air. The physical properties of the as-deposited as well

as the annealed samples were analyzed as a function of deposition pressure and laser fluence.

It was found that the deposited compounds are highly influenced by the background gas

pressure used during the deposition process. The samples were structurally characterized by

X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The as-

deposited films are amorphous. After the thermal treatment mixtures of vanadium oxides

together with the ternary compound Zn2V2O7 were found. The proportions of each compound

present in the sample depend on the deposition pressure. The optical characterization of the

films was carried out by means of UV-Vis and PL spectroscopies. Surface morphology of

the samples was analyzed by scanning electron microscopy. Structures with a variety of sizes

and shapes were found in the annealed films.




429

[ THF-143 ] Structural and optical properties of Sb2S3

thin films deposited by vacuum evaporation

R.G Sotelo Marquina 1 , N.R Mathews 1 , X. Mathew ([email protected]) 1

1 Instituto de Energía Renovables, Universidad Nacional Autónoma de México, Temixco,

Morelos, 62580, México

In this work we present the physical properties of vacuum evaporated Sb2S3 thin films. The

as-deposited films were amorphous and highly resistive. The film changed to polycrystalline

after annealing at 250 oC. The crystalline size of the film showed a systematic increase with

annealing temperature. The estimated values of lattice parameters were a= 1.1 nm b = 1.13nm

and c = 0.384 nm. At temperatures above 350 oC traces of Sb2O3 were

observed. Morphological studies showed a compact and void-free film surface. The band

gap calculated from optical study was about 2.1 eV and 1.87 eV respectively for as-deposited

and the film annealed at 350 oC. The films were photosensitive.

Acknowledgements:- Authors acknowledge Maria Luisa Ramon Garcia for the XRD

analysis, Jose Campos and Gildardo C. Segura for technical support in material

characterization. This work was supported by the projects: CONACYT Ciencia

Basica 238869, PAPIIT- IN107815, and CeMIE-Sol P28.




430

[ THF-146 ] Effect of deposition potential on physical

properties of electrodeposited Sb2S3 thin films

R.G Avilez Garcia 1 , C.A Meza 1 , M. Pal 2 , N.R Mathews


1 Instituto de Energías Renovables, Universidad Nacional Autónoma de

México, Temixco, Morelos 62580, México 2 Instituto de Física, BUAP, Av. San Claudio y Blvd. 18 Sur Col. San

Manuel, Ciudad Universitaria, C.P. 72570, Puebla, México

Thin films of Sb2S3 were fabricated by pulse electrodeposition on ITO glass substrates from

aqueous solution containing 0.5 mM SbCl3 and 0.25 mM Na2S2O3. The deposition was

carried out by applying potential pulses; the deposition potential (Von) was applied for 10s

which was followed by a dissolution potentials (Voff) for 10s. The thickness of the film was

controlled by the number of cycles. In the present work, we investigated the effect of

variation of deposition potential on the physical properties of Sb2S3 thin films. The films

were deposited at different Von: - 0.7V, -0.72 V, and -0.75V versus SCE. The dissolution

potential was kept constant at 0.1 V versus SCE. The structural, morphological and the

optical characterizations of the as deposited and annealed films were carried out using X-

ray, SEM, AFM, Raman spectroscopy and UV-VIS transmittance spectroscopy. The films

deposited at a potential of Von -0.72 V and Voff + 0.1 V vs SCE after annealing at 300 oC in

N2/S atmosphere were nearly stoichiometric, polycrystalline and photoconductive. The photo

conductivity of these films were in the range of 4 x10-7 (ohm-cm)-1 .

Acknowledgements: Authors acknowledge Maria Luisa Ramon Garcia for the XRD

analysis, Jose Campos and Gildardo C. Segura for material characterization. This work was

supported by the project: CONACYT Ciencia Basica 238869, PAPIIT-IN107815, and

CeMIE-Sol P28.




431

[ THF-190 ] Studies on optical and morphological

properties of ZnO thin films as function of the synthesis

technique employed.

Carlos Fernández 3 , Iván García Payán 3 , Manuel Pérez 3 , Alejandro

Ibarra Delgado 3 , Luis Castaños 3 , Gelacio Atondo 1 , Cristo Yee 1 , Oscar

Velarde 1 , Manuel García-Hipólito 2 , Francisco Ramos-Brito 1

1 Facultad de Ciencias Físico Matemáticas - UAS 2 Instituto de Investigaciones en Materiales - UNAM

3 student in Facultad de Ciencias Físico Matemáticas - UAS

Thin films of ZnO were synthesized by employing three techniques: Spray Pyrolysis,

Chemical Bath and Spin Coating. Films were obtained as function of different parameters

for each technique. Specular Reflectance, Transmittance, Photoluminescence (PL) at room

and low (20K) temperature and Scanning Electron Microscopy studies were done for all

samples. A comparison between energy gaps of all films is presented. The PL studies reveal

films that have an intense exciton emission (384 nm) and poor visible emission (defects) and

films that have poor exciton emission and intense visible emission, depending of the

technique employed and its parameter values. The visible emission present two principal

bands centered at 510 and 630 nm that were associated with typical structural defects. An

energy diagram that shows the differences in the excitation and decay mechanisms for ZnO

obtained by the three different techniques is presented. The films present morphology

conformed by nanoparticles that depends of the technique employed for the synthesis.




432

[ THF-203 ] Study of Magnetic Interactions in Zn1-

xMnxO/ Si (100) Thin Films

Carlos William Sánchez ([email protected]) 2 ,

Katherine Gross 2 , Wilson Lopera 2 , María Elena Gómez 2 , Pedro Prieto 1

1 Center of Excellence for Novel Materials CENM, Universidad del Valle, A.A. 25360, Cali,

Colombia 2 Thin Film Group, Department of Physics, Universidad del Valle, A.A. 25360, Cali,

Colombia

The effects of Mn concentration on the crystal structure, morphological and magnetic

properties of Zn1-xMnxO (0< x <0.3) thin films have been investigated by varying the

deposition temperature (300 oC < Td < 600oC) and thickness systematically. Thin films

growth was performed by RF sputtering technique with an oxygen pressure of 5.0x102mbar

from Zn1-xMnxO targets with a stoichiometric composition on (100) Si substrates. X-ray

diffraction (XRD) measurements reveal a (002) out-of-plane texture of the films and did not

reveal any Mn-based oxides compounds. The magnetic properties of the films have been

measured using vibrating sample magnetometer (VSM) at various temperatures with fields

up to 3KOe. Ferromagnetic ordering at room temperature has been evidenced in all

samples. Magnetic interactions have been studied using Delta-M plots as proposed by

Thamm and Hesse[1], their method uses the natural relationship between the initial curve

and hysteresis loop for the description of interactions of single-domain particles with uniaxial

anisotropy dispersed in a nonmagnetic matrix. With this method it was possible to recognize

magnetizing as well as demagnetizing interactions depending on Mn doping.

Acknowledgments: This work has been partially supported by CENM-UNIVALLE and

COLCIENCIAS-UNIVALLE research project C.I. 7917, C.C.10510, contract 2013-0002

and UNIVALLE research project titled “Development of room-temperature semiconducting

oxide nanostructures for silicon-based spintronics” with C.I. 7775.

[1] S. Thamm and J. Hesse, “A simple plot indicating interactions between single-domain

particles”, Journal of Magnetism and Magnetic Materials, Vol. 154, pp. 254-262, 1996




433

[ THF-211 ] Thin films of silicon dioxide-silver

nanoparticles (SiO2/Ag) by dip-coating

María del Carmen Flores Rodríguez ([email protected]) 1 ,

Fernando Díaz Monge ([email protected]) 1 , Fernando Roberto Vélez

Tenorio 1 , Esaú Solano Ruiz 1

1 Academia de ingeniería en materiales, Instituto Tecnológico Superior de Tlaxco, Predio

Cristo Rey Ex-Hacienda de Xalostoc S/N, Carretera Federal Apizaco-Tlaxco Km. 16.8,

Tlaxco, Tlaxcala.

Thin films of silicon dioxide-silver nanoparticles (SiO2/Ag) were synthesized, by the dip-

coating method to obtaining a homogeneous and high quality coating, for photocatalytic

applications, specifically for carbon monoxide (CO) to carbon dioxide (CO2) oxidation. The

synthesis of all solutions of SiO2/Ag was prepared from reduction of nitrate silver salt reagent

grade with sodium citrate, previously prepared of colloid silicon dioxide (SiO2)1. The

deposition was carried out on substrates glass on their surface chemically treated with piranha

solution to obtain a thickness of 3 µm by a dip coating, with a withdraw and immersion rate

of 100 mm/min and immersion time of the substrate in the solution, it was 6 seconds with

coating time 2 minutes.

The obtained samples were heat treated in a tubular furnace, to improve their adhesion to the

substrate. For the structural and morphological surface characterization samples, electron

microscope (SEM) observations were carried out. The composition and thickness of samples

were characterized by profilometry and Raman spectrophotometry.

Acknowledgements.

To technological institute and academy of engineering materials.

References

1. W. Stöber, A. Fink, E. Bohn, J. Colloid Int. Sci., 1968 (26) 62




434

[ THF-217 ] Obtaining thin films of titanium dioxide

(TiO2) by the Dip-Coating

Ana Olivia Quintero Pérez ([email protected]) 1 , Esaú Solano Ruiz


1 Ingeniería en Materiales, Instituto Tecnológico Superior de Tlaxco, Predio Cristo Rey Ex-

Hacienda de Xalostoc S/N, Carretera Federal Apizaco-Tlaxco Km. 16.8, Tlaxco, Tlax.

Thin films of titanium dioxide (TiO2) microspheres for photocatalytic applications carbon

monoxide (CO) to carbon dioxide (CO2) oxidation, on which gold nanoparticles (Au) are

supported, whose synthesis is performed in aqueous solution from auric tetrachloride (1mM),

using a concentration of 3 mM sodium citrate as reducing agent heated to 80 °C for 15 min.

The synthesis of TiO2 microspheres were conducted by the sol-gel method Stober. Obtaining

an average diameter of 0.12 µm. Deposition of films were carried out on glass substrates on

their surface chemically treated with piranha solution to a thickness of 170 nm by immersion

in colloidal sol using a dip-coating with immersion-emersion rate of 100 mm/min, with a

residence time of 6 seconds, and 2 min drying .

Each of the films obtained were thermally treated in a tubular furnace to obtain the desired

phase (anatase) in an oxidizing atmosphere, after which a sharp increase was observed in the

adhesion of the film deposited on the substrate surface. SEM analysis was performed

subsequently, profilometry and Raman analysis, for determination of the surface

morphology, thickness and phases present.

Acknowledgements.

To technological institute and academy of engineering materials.

References.

1. Suh HMS, Choi JR, Hah HJ, Koo SM, Bae YC (2004) J Photochem Photobiol A

Chem 163:37.

2. E. Nieto, F. Fernández, P. Duran y C. Moure. Instituto de Cerámica y Vidrio. CSIC.

Arganda del Rey. Madrid.

3. Lee, P. C., Meisel, D. Journal of Physical Chemistry 1982 (86) 33.

4. W. Stöber, A. Fink, E. Bohn, J. Colloid Int. Sci., 1968 (26) 62

5. D.Y. Nadargi, et.al. Journal of Alloys and Compounds 2010 (496) 436.




435

[ THF-247 ] Functionalization and characterization (a-

SiC:H) films

Ana Laura Perez Coyotl ([email protected]) 3 , Orlando Zaca

Moran 3 , Valentín López Gayou 3 , Abdu Orduña Diaz 3 , Placido Zaca

Moran 1 , José Luis Herrera Celis 2 , Claudia Reyes Reyes Betanzo 2

1 Benemérita Universidad Autónoma de Puebla, Instituto de Ciencias, Pue, México 2 Instituto Nacional de Astrofísica, Óptica y Electrónica,Santa María Tonantzintla,

Pue,México 3 Instituto Politécnico Nacional, CIBA-Tlaxcala, Tepetitla, Tlax, México

Thin films of a-SiC:H can be used as devices biolgicas applications have better stability

chemistry and biocompatibility compared to crystalline silicon carbide (Si-C), which are

being proposed as transducer biosensors for the detection of pathogenic microorganisms. In

this work samples of a-SiC:H obtained by Plasma Enhanced Chemical Vapor Deposition

PECVD were functionalized films were prepared by self-assembling 3-

aminopropyltrimethoxysilane in anhydrous toluene. Fourier transform infrared spectroscopy

(FTIR) and Atomic force microscopy AFM have shown process of funcionalized. The

presence of the amine group is evidenced in the peak at 1562 cm-1related to deformation

mode, and the two peaks at 3295 and 3368 cm-1 corresponding to symmetric and asymmetric

stretching modes, respectively. The peak at 1484 cm-1 and the shoulder at 1635 cm-1

correspond to the symmetricand asymmetric NH3 deformation modes FTIR spectra indicate

that film growth initially proceeds by adsorption of 3-aminopropiltrimethoxy silano to the a-

SiC:H surface followed by siloxane condensation, and after an extended period of time 3-

aminopropiltrimethoxysilane molecules accumulate on the underlying APTES film by either

covalent or noncovalent interactions. The surface topographies were observed using AFM we

observed the presence of many aggregates. The formation of aggregates may result from the

physical adsorption on the a-SiC:H of silanes prepolymerized in the solution, but it may also

be acase of surface nucleation.




436

[ THF-254 ] Electrochemical, microstructural and mechanical

characterization of TiHfN coatings deposited by Sputtering

Erika Luna Torres ([email protected]) 1 , Leandro García González 2 , Julián

Hernández Torres 2 , Luis Zamora Peredo 2 , Daniel de Jesús Araujo Pérez 2 , Héctor

Herrera Hernández 3

1 Instituto de Ingenieria, UV 2 MICRONA, UV

3 UAEM

In this work, TiHfN coatings were fabricated by Sputtering onto stainless steel 316, using

pressure values of 3.0x10-6 Torr, 4.0x10-6 Torr, 5.0x10-6 Torr and 6.0x10-6 Torr. The obtained

TiHfN coatings were evaluated by Electrochemical Impedance Spectroscopy to study their

corrosion resistance behavior, in an aggressive environment of NaCl at 0.5M exposed for 42

days. The microstructure and morphology of the coatings were studied by X-ray Diffraction

and Scanning Electron Microscopy. Additionally, hardness and vibrational modes were

obtained by Vickers indentation and Raman Spectroscopy respectively. Electrochemical

impedance results shows two time constants one at high frequency, which associates the

interface of the TiHfN coating with the electrolyte, and another at low frequency to the

specimen adsorbed on the coating, filling the pores, and causing a more homogenous

structure. Impedance values of 170000 ohm-cm2 were obtained. By scanning electron

spectroscopy was observed that the grain size decreases as the base pressure increases, being

the morphology of the sample at 6x10-6 Torr the most homogenous. The obtained hardness

values were about 29 GPa. With the X-ray diffraction results, the formation of a ternary cubic

phase of HfTiN2 was observed, with an intense reflection at 35.303° wich is related to an

preferential orientation of (1 1 1). However, at a minor pressure of 3x10-6 Torr a change in

the preferential orientation is seen to (2 0 0) at 40.991°. By Raman Spectroscopy four bands

were observed: the first order optical mode (O) at 415cm-1, the first order optical mode and

acoustic mode (O+A) at 680 cm-1 for the bond of HfN, the second order transversal acoustic

mode (2LA) at 475cm-1 for the TiN bonding and the transversal optical mode (TO) at 558

cm-1. The results demonstrated that the base pressure affects the microstructure of the

coatings as well as the efficiency of the protection against corrosion, unlike the hadrness

which do not affect the corrosion protection efficiency. The coatings synthetized at a pressure

of 6x10-6 Torr, are the most homogeneous with low porosity and therefore, they have a better

electrochemical behavior.

This research was supported by CONACYT by the project 154516. We thank at M.C. Daniel

Araujo Pérez, the M.I. Ayesha M. Courrech Arias for technical support and M.C. Angélica

Gutiérrez Franco by FESEM measurements.

Keywords: Sputtering, TiHfN, EIS, XRD, SEM, Raman, Vickers.




437

[ THF-261 ] Structural and optical properties of zinc

blende ZnO thin films

Lilia Martinez-Perez ([email protected]) 3 , Narcizo Muñoz-Aguirre

([email protected]) 2 , Jesus Eduardo Rivera-Lopez 2 , Orlando Zelaya-Angel

1

1 Departamento de Física del Centro de Investigación y de Estudios Avanzados del IPN,

CP. 07351, México, DF. 2 Instituto Politécnico Nacional, Sección de Estudios de Posgrado e Investigación, Escuela


Catarina. Del. Azcapotzalco, CP. 02250, México, D.F. México 3 Unidad Profesional Interdisciplinaria en Ingeniería y Tecnologías Avanzadas del Instituto

Politécnico Nacional, Av. IPN No. 2580, Col. Barrio La Laguna Ticomán, C.P. 07340,

México D.F. México.

Among the different phases in which zinc oxide can solidify in crystalline structure

hexagonal wurtzite (WZ), cubic zinc blende (ZB), cubic rock salt (RS), hexagonal

graphitelike, tetrapods are reported. Wurtzite is the crystalline stable phase in bulk at normal

temperature and pressure. Other phases are stable in special conditions, for instance, ZB is

the stable phase of nanoparticles condensed from smoke for less than 20 nm in size [1]. It is

well known that ZnO thin films in ZB phase have been obtained in epitaxial growth on cubic

substrates containing only a small number of monolayers. Recently, zinc oxide thin films in

cubic zinc blende (ZB) crystalline phase on glass substrates by means of the spray pyrolysis

technique were reported [2]. X-ray diffraction spectra showed that the ZB-ZnO films grow

highly oriented along the (004) crystalline direction. Atomic Force Microscopy images of

the surface exhibit nanometric structures with the approximated aspect of circular nanodiscs

in accordance with the spherical structures observed by means of Scanning Electron

Microscopy images. Optical absorbance measurements indicated that the forbidden energy

band gap is 3.18 ± 0.02 eV. Luminiscence spectra for zinc blende films showed two bands at

positions of 2.14 and 2.38 eV. Fluorescence spectra for hexagonal ZnO are centered at 2.83

eV. For zinc blende ZnO the fluorescence spectra showed bands centered at 3.27, 2.81, 2.64,

2.56 and 2.50 eV. In this work, a discussion about of the preliminary optical results is

presented.

[1] Shiojiri M, Kaito C, J Cryst Growth 1981;52:173.

[2] L. Martínez-Pérez, N. Muñoz-Aguirre, S. Muñoz-Aguirre and O. Zelaya-Angel,

Materials Letters 139 (2015) 63–65.




438

Acknowledgements. Work partially supported by Instituto Politécnico Nacional from

México with the project number SIP-20151005. Authors also would like to acknowledge the

technical assistance of Ing. Ana Berta Soto and QFB. Marcela Guerrero both from the

Physics Department of CINVESTAV-IPN. Authors give thanks to Dra. Margarita

Mondragón Chaparro by the using of their facilities from the Sección de Estudios de

Posgrado e Investigación de la ESIME Unidad Azcapotzalco.

[ THF-263 ] Study of the influence of thermal oxide

thickness and rhodamine 6G concentration on the

fluorescent properties of PSi single layers.

Viridiana Aca-López ([email protected]) 1 , Estela Gómez-Barojas 1 , Rutilo Silva-

González 3 , J. Alberto Luna-López 1 , Claudia Reyes-Betanzo 2 , Enrique Sánchez-Mora 3 ,

Francisco Flores-Gracia 1

1 CIDS-IC, Benemérita Universidad Autónoma de Puebla. Apdo. Postal 196, Puebla, Pue.

72000. México. 2 Instituto Nacional de Astrofísica Óptica y Electrónica. Tonantzintla, Puebla, México

72840 3 Instituto de Física, Benemérita Universidad Autónoma de Puebla. Apdo. Postal J-48,

Puebla, Pue. 72570.

Key words: Porous silicon, Rhodamine 6G, Fluorescence

Dye molecules embedded in solid state matrices have emerged as potential non linear optical

materials. Different methods to trap organic molecules within solid substrates have been

developed, including direct soaking of the host with dye solutions where the chemical bond

between organic molecules and inorganic matrices is weak (hydrogen bonding, Van der

Waals interactions, etc). This class of hybrids can be obtained through impregnation of solid

hosts with solution of the desired molecule [1,2]. In the other hand, rhodamine is a

fluorophore that presents good photophysical properties such as high absorption coefficient,

high fluorescent quantum yield, high photostability and relative long emission wavelength.

One common use of rhodamine is for labeling antibodies. In the present work, the effect of

rhodamine 6G (Rd-6G) concentration in the fluorescence of infiltrated Porous silicon single

layers has been studied, and due to the cationic character of Rd-6G, the effect of SiO2

thickness thermally grown on PSi to enhance the Fluorescence properties of PSi has been

studied as well. PSi single layers have been synthesized by electrochemical etching of

polished silicon p-type wafers (100) orientation and 0.01-0.02 Ω∙cm resistivity. Silicon

substrates were chemically degreased and native residual surface oxide removed before




439

anodizing. The etching solution contained ethanol (purity 99.5%), hydrofluoric acid (45%)

and glycerol (99%), at volumetric proportions 60:30:10. Porous silicon single layers were

synthesized in a two electrodes electrochemical Teflon cell. The as anodized PSi single layers

were thermally oxidized since it is known that the rhodamine is a cationic dye that interacts

preferentially with oxygen terminated PSi. Two oxidation conditions were used. Then, the

PSi single layers were silanized by dipping them into a solution formed with 2.5 v/v of 3-

mercaptopropyltrimethoxysilane (MPTS) in 2-Propanol solution for 15 min. Finally, they

were infiltrated by dipping them into a solution containing Rd-6G and ethanol as solvent, for

1 h. The Rd-6G concentration in the infiltrating solutions was varied from 0.4 to 4.0 mM

with 0.4 mM increment. From the comparison of Fluorescence spectra of PSi single layers

slightly oxidized with the ones of thicker oxidized, it is proved that Rd 6G is well adsorbed

on the PSi oxidized layers but a very thin oxide enhances the FL of the infiltrated PSi layers

while a thicker one is opaque to the PSi fluorescence. Furthermore, the intensities of

Fluorescence spectra have shown a non linear relation of fluorescence intensity with respect

to Rd-6G concentration.

Acknowledgement.

This work has been partially supported by CONACYT through a scholarship. The authors

acknowledge Dr. Mariano Aceves Mijares from INAOE for his help in the samples

fluorescence measurements.

References:

[1] P. Proposito and M. Casalboni, Handbook of Organic-Inorganic Hybrid Materials and

Nanocomposites, Vol. 1 (American Scientific Publishers, 2003).

[2] R. Reisfeld. Opt. Mater. 16 (2001) 1.




440

[ THF-286 ] Synthesis and characterization of gallium

oxide thin films prepared by sputtering.

Elizabeth Galván 1 , Mario Fidel García Sánchez ([email protected]) 2 ,

Orlando Zelaya 1 , Marcelino Becerril 1

1 Departamento de Física, CINVESTAV- IPN, A.P. 14-740, C.P. 07000, México D.F. 2 Unidad Profesional Interdisciplinaria de Ingeniería y Tecnologías Avanzadas, Instituto


Galium oxide thin films have been prepared on single-crystalline silicon substrates and quartz

at room temperature by sputtering. The synthesis was prepared from a target with a mix of

gallium nitride and metallic gallium. Influence of RF power and pressure was evaluated. The

morphology and structure were studied by X-ray diffraction (XRD), scanning electron

microscopy (SEM), atomic force microscopy (AFM), Raman, ellipsometry, profilometry,

optical absortion (UV) and photoluminiscence (PL). Even when gallium nitride is

representative in the target, Raman and UV measurements show that the obtained films were

composed by gallium oxide. PL measurements show wide bands, in the range of 400-650

nm, which are associated with defects in the structure. The refractive index measurements

indicate the presence of dense materials.

Keywords: gallium oxide thin films, sputtering, photoluminiscence.




441

[ THF-296 ] Structural, optical and morphological

characterization of CdS thin films for organic solar cells.

Susana Meraz Dávila ([email protected]) 1

1 CINVESTAV

Cadmium sulphide thin films were grown by photochemical deposition technique (PCD)

from an aqueous ammonia-free solution at room temperature. Thin films were synthesized at

different deposition times from 60 to 300 minutes; and were characterized by X-ray

diffraction, optical transmission spectroscopy and scanning electron microscopy. Preliminary

results demonstrated polycrystalline and highly oriented films, having an hexagonal phase

with a preferred orientation at plane (0 0 2), homogeneous smooth films were observed with

a clear change in thickness with respect of deposit time, having a uniform size and shape of

CdS grains very well adhered to the substrate surface, with a high quality and good absorption

in the visible region with a band gap of 2.3 eV.

The CdS/Poly(3-hexylthiophene-2,5-diyl) (P3HT) hybrid devices were fabricated by drop

casting process and different material contacts were evaluated; the influence of UV radiation

and photovoltaic performance was studied with respect to the power conversion efficiency

exhibiting efficiencies from 0.007 % for P3HT:CdS hybrid devices.

The photochemical deposition proposed in this work is a direct, fast, simple, and inexpensive

via process and due of this optimal features has a great potential for photovoltaics device

applications.




442

[ THF-298 ] Enhancement photocatalytic activity of

ZnTiO3-CdS composites films prepared by sputtering

process

Yuliana de Jesus Acosta-Silva ([email protected]) 1 , Arturo Mendez-

Lopez 2 , Orlando Zelaya-Angel 1

1 Depto. de Física, Centro de Investigación y de Estudios Avanzados del Instituto

Politécnico Nacional, Avenue IPN No. 2508, 07360 Mexico City, DF, Mexico 2 Sección de Electrónica del Estado Solido (SEES), Depto. de Ingeniería Eléctrica, Centro

de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Avenue IPN

No. 2508, 07360 Mexico City, DF, Mexico

ZnTiO3-CdS composites films were prepared on glass substrates by sputtering process and

their photocatalytic activity toward the degradation of methylene blue (MB) was

measured. ZnTiO3-CdS films were characterized by diffraction (AFM), X-ray diffraction

(XRD), UV–vis diffuse reflectance spectroscopy (UV-vis DRS), scanning electron

microscopy (SEM) and, high resolution transmission electron microscopy (HRTEM).

The ZnTiO3-CdS fims were found to be more active than pure ZnTiO3. The highest activity

of ZnTiO3-CdS composites was due to coupling of two semiconductor nanoparticles reduce

the recombination of electron-hole pairs and consequently achieving a higher photocatalytic

activity.




443

[ THF-303 ] Determination of adhesiveness between a

biodegradable material (PLA) and cellulose

Magdalena Trujillo ([email protected]) 2 , Alejandro Vargas

([email protected]) 2 , Alfredo Maciel 1 , Marissa Morales 1

1 Materials Research Institute, UNAM 2 Plastics processing lab, Design and Mnufacture department, Faculty of Engineering,

UNAM

Nowadays, biodegradable materials have been the most important upswing for the plastic

industry. The government's concern to maintain a country free of solid waste has led

researchers and scientists to develop materials and processes that contribute to the requested

demands. The following work is based on the study of adhesive compatibility between a

biodegradable material and a cellulose-based material. Obtaining biodegradable material in

film form was performed under the extrusion process, designing the die by means of

rheological principles allowed to obtain a preferential orientation, thus favoring the union

between both materials. Through analysis and tests of adhesion under international standards,

the quality of the bond was determined among the materials presented.

References

[1] M. Madrid Vega y J. M. Martín Martínez, Tecnología de la adhesión, España:

Departamento Técnico de Loctite, 2009.

[2] C. Rauwendaal, Understanding Extrusion, München: Carl Hanser Verlag, 2010.

[3) L. Tin Sin , A. Razak Rahmat y W. A. Wan Abdul Rahman, Polilactic Acid, PLA

Biopolymer Technology and Aplications, Oxford: Elsevier Inc, 2013.

[4] National Institute of Industrial Research, The Complete Book on Biodegradable Plastics

and Polymers, Delhi: Asia Pacific Business Press Inc., 2006.




444

[ THF-311 ] Structural characterization of layers of

GaAs (Mn,Cr) and multilayer of GaAs / (Mn,Cr) grown

by magnetron sputtering rf

J. Doria ‐ Andrade ([email protected]) 1 , R. Medina ‐ Echavarría 3 , C.

Pulzara ‐ Mora 3 , R. Bernal ‐ Correa 3 , A. Rosales ‐ Rivera 2 , A. Pulzara ‐ Mora 3

1 Escuela de Física, Universidad Nacional de Colombia, sede Medellín. A.A. 568, Medellín,

Colombia. 2 Laboratorio de Magnetismo y Materiales Avanzados, Universidad Nacional de Colombia,

sede Manizales. A.A. 127, Colombia 3 Laboratorio de Nanoestructuras Semiconductor, Universidad Nacional de Colombia, sede

Manizales. A.A. 127, Colombia.

Diluted magnetic semiconductors (DMS) based on III-V doped with Mn, Cr and Co are of

great scientific and technological interest because they are materials in which the magnetic

and transport properties are coupled so that the magnetization state modify the properties of

the material transport. In this paper the results of the preparation and characterization of GaAs

layers are as follows: Mn by rf magnetron sputtering on glass substrate and silicon in order

to study their properties estructructurales. The growth was carried out alternating layers of

GaAs /Mn and GaAs/Cr layers and GaAs (Mn) and GaAs (Cr) from targets GaAs ,Mn

y Cr during certain time periods. In the XRD analysis (θ - 2θ) it was observed a characteristic

peak at 2θ = 66.1° due to the addition of Mn in the GaAs matrix. In addition to the main

peaks appeared GaAs not defined, such as (220) and possibly other peaks correspond to

phases α- Mn and Ga5Mn8 as a function of temperature and the content of Mn -. Cr. Also

better growth observed in GaAs / Mn on glass substrate at low temperatures for Mn.




445

[ THF-327 ] Fabry-Perot filters in the UV as a result of

oxidized porous silicon multilayer

María del Rayo Jiménez Vivanco ([email protected]) 2 , Godofredo

Gacía ([email protected]) 6 , Francisco Morales 5 , Hector Juárez 7 ,

Mauricio Pacio 4 , Tomas Díaz 1 , Gabriela Nieto 3

1 Becerril 2 CIDS-BUAP, Ed. 103-C, Col. San Manuel. Puebla, Pue.

3 Caballero 4 Castillo 5 Morales 6 Salgado

7 Santiestaeban

This work presents an experimental study of the evolution of the spectral reflectance of

porous silicon multilayers (PSM), which were obtained by electrochemical anodization of p+

type crystalline silicon substrates in aqueous hydrofluoric acid solutions and ethanol. The

Fabry-Perot filter (FPF) produced by the PSM were obtained by alternating high and low

refraction index of porous silicon PS with two Bragg reflectors and an active layer. The

dependence of the porosity on the effective refractive index for porous silicon is limited by

curves for the two-component media: silicon and air, using the Bruggeman effective medium

approximation, this simple model is applicable to porous materials. FPF were subjected to a

thermal oxidation process creating an oxidized porous silicon that induce a shift of the

response to the ultraviolet (UV) from 505 to 370 nm in the peak minimum of the reflectance

spectrum. The shift is explained as due to the formation of silicon dioxide, which has a lower

refractive index than that of silicon. The oxidation causes changes in the optical

characteristics of FPF, decrease the refractive index and the optical path, while keep the

physical thickness, this due to the good penetration of the oxide and the design of the PSM.

It was used a model to predict the behavior of our FPF that contains refractive index of

silicon, silicon dioxide and air. Characterization of FPF was performed by UV-Vis-NIR

spectroscopy before and after the oxidation process.

Keywords: Oxidized porous silicon, Fabry-Perot filter, Ultraviolet.




446

[ THF-348 ] Synthesis of Sr²⁺ doped SnO2 coatings and

modified with pmma applied for corrosion protection

Ana Karen Acero Gutiérrez ([email protected]) 1 , Ángel de Jesús

Morales Ramírez ([email protected]) 1 , Jesús Gilberto Godínez

Salcedo 2

1 CIITEC-IPN Cerrada de Cecati s/n, Azcapotzalco, Santa Catarina, 02250 Ciudad de

México, D.F. 2 ESIQIE-IPN U. Prof Adolfo López Mateos, Gustavo A. Madero, Ciudad de México, D.F.

Nowadays, some materials, because its highly demanding operative conditions, need to

present a superior corrosion resistance, wear resistance, high hardness and nontoxic. In this

work, SnO2 coatings doped with strontium have been developed by sol-gel method using tin

(II) chloride and strontium acetate as matrix and dopant precursors respectively; furthermore,

the sol was modified by the incorporation of PMMA (polymethylmethacrylate) to compare

their properties against corrosion process when is deposited on 304 stainless steel by dip-

coating technique. Chemical evolution of the sol-gel process, crystal structure and

morphology were examined by Fourier Transformed Infra-Red, X-Ray Diffraction, Scanning

Electron Microscopy and Atomic Force Microscopy techniques, and the effect of the effect

of the content of strontium (Sr²⁺) and PMMA were studied. The corrosion protection of the

prepared coatings will be evaluated in simulated marine environment in 3 wt. % aqueous

NaCl solution by potentiodynamic polarization.




447

[ THF-359 ] Processing of TaN by UHV sputtering

Yuri Lizbeth Chipatecua Godoy ([email protected]) 1 , Oscar

Ceballos Sanchez 1 , Zeuz Montiel Gonzalez 1 , Jhon Jairo Olaya Florez 3 ,

Wencel De La Cruz 2 , Alberto Herrera Gomez 1

1 CINVESTAV-Unidad Queretaro. Queretaro, Qro. 76230, Mexico 2 Centro de Nanociencia y Nanotecnología. Universidad Nacional Autónoma de México,

22860, Ensenada, B.C., México 3 Departamento de Ingenieria Mecanica y Mecatronica, Universidad Nacional de

Colombia, Botoga D.C., Colombia

The transition metal nitride films deposited by PVD techniques, such as reactive magnetron-

sputtering, are well established for modifying mechanical properties on the surface. This is

the case of TaN coatings that have excellent properties as hard films and have been

extensively used in industry to protect base materials against fatigue, wear, corrosion and

many other surface-related damage phenomena. These properties include high hardness and

conductivity, chemical inertness, wear and corrosion resistance, chemical and thermal

stability and biocompatibility.

In this study, TaN films were deposited using an ultra-high-vacuum (UHV) sputtering

system. The working pressure was ~ 5×10-3 Torr and the base pressure 1×10-8 Torr. The

processing conditions (substrate temperature, Ar and N flow rate, bias, and discharge current)

were optimized to obtain high quality TaN films. The composition was evaluated using x-

ray photoelectron spectroscopy (XPS) and XPS-Sputter. Mechanical properties such as

hardness and adherence were evaluated using nanoindentation and pin on disc tests. The

thickness was characterized through perfilometry.

Acknowledgments

The authors would like to acknowledge Martín Adelaido Hernandez and José Alfredo Muñoz

for his technical support.




448

[ THF-371 ] Synthesis and characterization of CdTe

nanoparticles embedded within a silicon dioxide matrix

Andrea Pamela Chavelas González ([email protected]) 4 ,

Arturo Hernández Hernández 2 , Luis Alberto Hernández Hernández 3 ,

Alejandra roció García Sotelo 1 , Miguel Ángel Meléndez Lira 1

1 Departamento de Física, Centro de Investigación y de Estudios Avanzados del Instituto



U.P. Adolfo López Mateos, Col. San Pedro Zacatenco, C.P. 07730 México DF, México. 4 Universidad Politécnica del Valle de México, Av. Mexiquense s/n, esquina Av.

Universidad Politécnica, Col. Villa Esmeralda, C.P. 54910, Tultitlán, Estado de México.

The current requirements of optimal materials for optoelectronics applications require to

have some control mechanisms for the size particle distribution of materials obtained by self-

assembly processes; that control could improve their application in different devices.

In this work we report the synthesis of self-assembled systems produced via a sequential

deposition process of SiO2/CdTe/SiO2 layers using the RF reactive sputtering techniques and

its optical, electrical and structural characterization.

The samples were prepared on silicon (111) p-type substrates and commercial glass. In order

to control the spatial distribution and the CdTe particle size the surface defects induced by

variation of the reactive atmosphere in the production of the first SiO2 layer were used.

The images of transmission electron microscopy shown a distribution of nanoparticles with

sizes between 10 and 15 nm. The results of X-ray diffraction confirm the presence of CdTe

nanoparticles. The results of transmittance, photoluminescence and Raman spectroscopies

are discussed in terms of the nanoparticles size.




449

[ THF-380 ] Electrical characterization of of self-

Assembled ZnO nanoparticles embedded in a silicon

oxide matrix produced by reactive RF sputtering.*

C. Atzin-Mondragon 1 , R. Escobedo-Alcaraz 1 , A.P. Chavelas-González 4 ,

A. Hernández-Hernández 2 , L.A. Hernández-Hernández 3 , A.R. García-

Sotelo 1 , M. Meléndez-Lira ([email protected]) 1



Chimalpa Tlalayote S/N Col. Chimalpa, Apan, Hidalgo. México 3 Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, Edificio 9

U.P. Adolfo López Mateos, Col. San Pedro Zacatenco, C.P. 07730 México DF, México 4 Universidad Politécnica del Valle de México, Av. Mexiquense s/n, esquina Av.

Universidad Politécnica, Col. Villa Esmeralda, C.P. 54910, Tultitlán, Estado de

Silicon dioxide and metallic Zn films were deposited employing silicon and zinc

targets. An oxygen rich working plasma was employed. A sequential deposition

of SiO2/Zn/SiO2 films were deposited ; SiO2 layer was produced at 400 °C while deposition

temperature of Zn layer was changed between 100 and 500 °C. The electrical transport

properties were characterized by the Van deer Paw technique, IvsV and spectral response.

Results indicated the formation of ZnO nanoparticles with a dependence on the Zn growth

temperature.





450

[ THF-396 ] Synthesis and characterization of CeO2,

La2O3 and codeposit thin films by RF magnetron

sputtering on AA6082 aluminium alloy

Silvia Beatriz Brachetti-Sibaja 1 , Silvia Beatriz Brachetti-Sibaja

([email protected]) 2 , Sandra Rodil 3 , Miguel Antonio Domínguez-

Crespo ([email protected]) 1 , Aidé Minerva Torres-Huerta 1 ,

Eugenio Rodríguez 1

1 IPN, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada-Unidad

Altamira. Km 14.5 Carr. Tampico-Pto. Industrial Altamira, Altamira Tamps. C.P. 89600. 2 TecNM, Instituto Tecnológico de Cd. Madero. Ave. Primero de Mayo s/n Col. Los

Mangos Cd. Madero Tamps. C.P. 89440. 3 UNAM, Instituto de Investigaciones en Materiales, Circuito Exterior s/n C.U. Coyoacán,

C.P. 04510, México D.F.

In spite of the high potential applications of rare earth thin films, only few studies have been

made to prepare them by radio frequency magnetron sputtering as anticorrosive protector. In

the present work, cerium and lanthanum oxide films were co-deposited by r.f. magnetron

sputtering from a CeO2 and La2O3 target in an argon atmosphere (20 mTorr). The films were

deposited onto Si(100), glass and AA6082 aluminum alloy substrates. Two different RF-

powers were tested (60 and 90 watts) and for each power, the deposition time was changed

from 25, 40 and 60 minutes, as well as the substrate temperature (ambient and 200°C). The

structure, morphology and chemical composition was studied by X-ray Diffraction (XRD),

X-ray Photoelectron Spectroscopy (XPS), and Scanning Electron Microscopy (SEM),

respectively. The thickness of the thin films was obtained by ellipsometry spectroscopy. The

protective character was evaluated on the aluminum alloy substrate by Open Circuit Potential

(OCP), Polarization Resistant (Rp), Electrochemical Impedance Spectroscopy (EIS) and

Potentiodynamic Polarization Curves. Electrochemical evaluated indicated that the rare earth

films behave as cathodic inhibitors. The lanthanum oxide thin films are more protective as

cerium oxide probably because is very reactive in contact of atmosphere, producing La(OH)3

with a corrosion velocity of 546.0 x 10-6 mpy (1.39 x 10-5 mmpy).

Acknowledgements to CONACYT CB-2009, SIP 2015-0202, 2015-0227 and PAPIIT

103910.




451

[ THF-405 ] Structural and optical properties of TiO2

thin films deposited by laser ablation under ambient air

M. M. Barajas-Carrillo 2 , A. Pérez-Centeno 1 , G. Gómez-Rosas 1 , M. A.

Santana-Aranda 1 , J. G. Quiñones-Galván ([email protected]) 1

1 Departamento de Física, CUCEI, Universidad de Guadalajara 2 Licenciatura Ingeniería en Comunicaciones y Electrónica, CUCEI, Universidad de

Guadalajara

Thin films of TiO2 were deposited by laser ablation. High purity Ti and compressed TiO2

powders were used as target materials. Two samples were deposited from each target at

different laser fluence values in order to get low and high mean kinetic energies of the Ti

ions in the plasma. The deposition chamber was initially heated and evacuated to a

background pressure of 10-6 Torr to eliminate water traces in the chamber. The working

pressure was kept constant at 10-3 Torr of ambient air for all the experiments. Two additional

samples were deposited from TiO2 target in vacuum (10-6 Torr) with the aim of evaluate

oxygen loss during the ablation process. The optical and structural properties of the films

were studied as a function of the target and laser fluence.

Acknowledgements: Authors want to thank the technical support of Sergio Oliva. This work

was partially supported by CONACyT (grant CB2010-156773) and U. de G. (programs pro-

SNI and PROINPEP).




452

[ THF-421 ] Operation of Extended-Gate ISFETs

Employing a Thin-Layer of ALD Al2O3 as the Sensitive

Dielectric

Berni Manolo Perez Ramos ([email protected]) 1 , Joel Molina Reyes 1

1 Departamento de Electrónica, Instituto Nacional de Astrofísica, Óptica y Electrónica,

Luis Enrique Erro 1, Tonantzintla, Puebla, México, 72000

One of the major advantages of solid state sensors is the possibility to integrate them in a

chip along with control, signal processing and conditioning circuitry. However, there are still

some difficulties with the integration of ion sensors due that these devices usually operates

immersed in chemical solutions. Additionally, the materials employed in the fabrication of

chemical sensors must be selected in such a way that the sensitivity is maximized and, at the

same time, the compatibility of the fabrication process is maintained. For these reasons, this

work presents the operation of Extended-Gate ISFETs (EG-ISFET) fabricated with a

conventional CMOS process (MOSIS 0.5 um). The extended gates were obtained by using

the top metal layer as sensing layers, connected to the polysilicon gate of a conventional FET.

The sensors were then covered by a thin-film of Atomic Layer Deposited (ALD) Al2O3 used

as the sensitive dielectric, and at the same time providing an additional passivation layer to

protect the electrically active areas of the chip.

It is shown that these sensors operate with an almost ideal Nernstian sensitivity to pH

changes. Besides, the compatibility of the fabrication of chemical sensors with a conventional

CMOS process and the application of ALD dielectrics as sensitive layers is fully

demonstrated.




453

[ THF-430 ] Optical and structural properties of gan

grown by sublimation into tube furnace

Luis Alberto Hernández-Hernández ([email protected]) 2 ,

Gerardo Contreras-Puente 2 , Francisco de Moure-Flores 4 , Jorge Aguilar-

Hernández 2 , Osvaldo de Melo-Pereira 3 , Karla Gutiérrez-Z-B 2 , Máximo

López-López 1 , Guillermo Santana-Rodríguez 5

1 Departamento de Física, Centro de Investigación y de Estudios Avanzados - I.P.N.,

C.P.07360 México, D.F. 2 Escuela Superior de Física y Matemáticas – Instituto Politécnico Nacional, Edificio No.

9, U.P.A.L.M., San Pedro Zacatenco, C.P. 07738 México D.F. 3 Facultad de Física de la Universidad de La Habana, Colina Universitaria, 10400, La

Habana, Cuba 4 Facultad de Química, Universidad Autónoma de Querétaro, Querétaro C.P. 09790

México 5 Instituto de Investigación en Materiales Universidad Nacional Autónoma de México,

Coyoacan, C.P. 04510 México D.F.

We report in this work the structural and optical properties of GaN films grown by

sublimation employing a tube furnace without any additional source of nitrogen during the

process. The samples were deposited on p-type silicon (1 1 1) substrates using GaN powder

(99.999% purity) as material source.The GaN powder as well as the substrate were contained

inside a semi-hermetic cell made of graphite at ambient atmosphere. Structural and optical

characterization obtained through X-Ray Diffraction (XRD), Scanning Electron Microscopy

(SEM), Energy Dispersive Spectroscopy (EDS) and Photoluminescence (PL) measurements

are presented. XRD diffractograms exhibit the growth of policrystalline hexagonal GaN.

Concerning EDS measurements they shows the presence of stoichiometric GaN. Finally, PL

measurements under UV excitation (He:Cd laser λ=325 nm) confirm the emission at room

temperature. A deeply discussion of the results are presented and discussed.

†The authors acknowledge financial support for this work from FONDO SECTORIAL

CONACYT-SENER-SUSTENTABILIDAD ENERGÉTICA through CeMIE-sol, within of

the strategic project number 37; “Development of new photovoltaic devices and semi-

superconductor materials”.




454

[ THF-460 ] Effect of sputtering parameters in the

properties of TiO2 and TiN thin films

Andrés González-Hernández ([email protected]) 1 , Andrés González-Hernández

2 , Miguel Antonio Domínguez-Crespo ([email protected]) 1 , Tomás Lozano-

Ramírez 2 , Deyanira Del Ángel-López 1 , Aidé Minerva Torres-Huerta 1 , Silvia Beatriz

Brachetti-Sibaja 2

1 IPN, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad

Altamira. Km 14.5 Carr Tampico-Pto Industrial Altamira, Altamira Tamps. C.P. 89600 2 TecNM, InstitutoTecnológico de Cd. Madero. Ave. Primero de Mayo s/n Col. Los Mangos

Cd. Madero Tamps. C.P. 89440

The titanium oxide (TiO2) thin films have been investigated in recent years for their

interesting properties. It has a wide range of applications like antireflection and protective

coatings, gas and humidity sensors, solar energy converters among others. The TiO2 has three

crystalline structures, brookite (orthorhombic), anatase and rutile (tetragonal) each phase has

characteristic properties that make them desirable for specific applications. On the other

hand, the titanium nitride (TiN) is an extremely hard ceramic material and has been used in

the form of thin films to increase hardness in cutting tools and as non-toxic exterior for

medical implants, its crystalline phases are face centered cubic δ(TiN) and hexagonal

ε(Ti2N). Both titanium thin films can be obtained by sputttering deposition, a process

whereby atoms are ejected from a solid target material due to bombardment of the target by

energetic particles. All the properties of these thin films can be affected by the synthesis

parameters. In the present work, TiO2 and TiN films were deposited by radiofrequency

magnetron sputtering (RF-magnetron sputtering) using a titanium target in glass and steel

AISI 1065 substrates, respectively. The sputtering parameters of time (15 - 120 min), RF-

power (100 - 200 watts), working distance (11 - 17 cm), the flow rate of Ar for TiO2 and the

gas ratio of Ar/N2 for TiN were changed, to obtain different thin films and after the deposition

were thermal treated to different temperatures in a range of 200 - 400 °C. The XRD patterns

of TiO2 obtained with 200 watts, 120 min and 300 °C; showed the structure of anatase phase

that is characterized by films color steely glint, this phase has semiconductor characteristics

and is used in photocatalyst applications. The TiN films color varies strongly with the

composition; in the TiN films obtained with a working distance of 17 cm, 160 watts and 150

min results in thin films color gold characteristic of the TiN. However, with major power

(200 watts), the films were color blue and using a power of 100 watts the thin films were

color purple, the coloration was influenced by the Ar/N2 gas ratio, the working distance and

the RF-power, this can be due to the kinetic energy generated in the plasma during the

collision impact of argon ions and titanium causes mixes with small amounts of oxygen

generating an oxidation with sub-products like TiO2 which strongly affect the TiN properties

like hardness and adhesion.




455

[ THF-463 ] Comparative study of ZnO thin films

prepared by PLD using nanoparticles ZnO mixed in a

cyanoacrylate target and ceramic target

Enrique Josué Chan y Díaz ([email protected]) 1 , Román Ernesto

Castro Rodríguez ([email protected]) 2

1 Departamento de Ingeniería Mecánica, Instituto Tecnológico de Mérida, Av. Tecnológico

km. 4.5 S/N, 97118, Mérida, Yucatán, México. 2 Department of Applied Physics, CINVESTAV-IPN, Unidad Mérida. 97310 Mérida

Yucatán, México.

ZnO thin films were deposited on ITO substrates using the Nd:YAG-laser ablation method

and a target made up of powder nanoparticles with a size of less than 100 nm mixed with

cyanoacrylate glue (composite target). In this study, the structural and optical properties of

the ZnO thin films deposited using this target compared to those of the ZnO thin films

deposited using a traditional target made up of sintered powder (sintered target) were

examined. The ZnO thin films deposited using the composite target at substrate temperature

of 300 ºC were polycrystalline with preferential orientations in the planes (100) and (101),

grain size of ~40 nm, in the visible range and showed a high resistivity of ~1.30×102 Ω-cm,

indicating that these films showed more enhanced properties than the ZnO thin film deposited

using sintered target, this allows the thin films obtained by the former target to be used as

buffer and anti-reflective layer in solar cells based in CdTe. The enhanced properties of the

ZnO thin film prepared with composite target were considered to be caused by the notable

improvement in packing density and high transmittance over an average of 85% surface

roughness, which were observed from atomic force microscopy (AFM) images due to the

composite target consisting of nanoparticles embedded into a matrix of cyanoacrylate glue.

Keywords: ZnO thin film, PLD, cianoacrylate, ZnO buffer layer, ZnO anti-reflecting.

This work has been supported under Project No. CB/1012/178748 CONACYT/México




456

[ THF-466 ] influence of the cr incorporation on the

structure of sputtered ZrN films deposited at low

temperatures

A. M. Villegas Mercado 3 , A. Esparza Hernández 3 , J. J. Ortega

([email protected]) 3 , F. Puch Ceballos 3 , R. Escobedo-Galindo 2 , C.

Falcony 1 , J. J. Araiza 3

1 CINVESTAV, IPN, Distrito Federal, México. 2 ICMM, CSIC, Madrid, España

3 Unidad Académica de Física, UAZ, Zacatecas, México.

We have studied the influence of the Cr incorporation in the crystalline structure of ZrN thin

films deposited by DC magnetron co-sputtering processes at low temperature. The amount

of the chromium in the films depends directly on the power applied to the chromium cathode

during the deposition. Energy Dispersive X-Ray (EDX) analysis and X-ray Diffraction

(XRD) analyzed the chemical composition and the crystalline structure of the films,

respectively. Steel sheets and crystalline (100) Silicon wafers were used as substrates. When

Cr atoms are incorporated into the ZrN coatings, the strong ZrN (200) preferred orientation

is modified to a combination of phases such as ZrN (111), Zr3N4 (211). FTIR (Fourier

Transform Infrared Spectroscopy) allowed us to complete the identification of the nitrides

and oxides incorporated into the deposited films.




457

[ THF-472 ] Piezoresistive Sensor Made of Graphite

Films Deposited by Direct Friction

Renan Gabbi 1 , Graciane Hammes 1 , Geferson Gustavo Wagner Mota da

Silva 1 , Luciane Scarton 1 , Luiz Antonio Rasia 3 , Antonio Carlos Valdiero 2

, André Luciano Rakowiski 1

1 Unijuí / DCEEng - Department of Science and Engineering, Lulu Ingelfritz Street, 480,

Ijuí, Brazil 2 Unijuí / DCEEng - Department of Science and Engineering, Rudi Franke Avenue, 540,

Panambi, Brazil 3 Unijuí / DCEEng - Department of Science and Engineering, Sao Francisco Street, 501,

Ijuí, Brazil

Flexible electronic devices can be produced by depositing single or multiple layers of

functional materials, such as conductive, resistive, semi-conductive or dielectric inks, onto a

flexible substrate.Today, the application of some of these materials is being performed by

high cost, small capacity processes such as physical and chemical vapor deposition,

sputtering and spin coating. In this paper we use graphite pencil lines of different hardness

and lengths and widths controlled on polyester substrates and paper and build a sensor to

mechanical stress. The devices were manufactured by drawing a line 0.5 cm wide and 6 cm

long. Contacts were made using conductive silver ink and the electrical resistance was

measured. Resistivity measurements, film thickness and the number of atoms in the deposited

layer were estimated through indirect methods. The deposition friction graphite on flexible

substrates made possible to identify the main characteristics of the film at a relatively low

cost, compared with traditional deposition methods. The results obtained allowed to extract,

through mathematical models, the sensitivity factor and the cross effects of electrical,

mechanical and thermal properties of these films have been used as piezoresistor.




458

[ THF-483 ] effects of annealing temperature on co-

sputtered P type ZnO:Ag,N thin films

S. F. Ocón Trejo 2 , L. A. Sandoval Vázquez 2 , J. J. Ortega

([email protected]) 2 , M. L. Pérez Arrieta 2 , C. Falcony 1 , J. J. Araiza 2

1 CINVESTAV, IPN, Distrito Federal, México. 2 Unidad Académica de Física, UAZ, Zacatecas, México.

Ag and N dual acceptor doped ZnO thin films were deposited on GaAs (100) substrates by

DC reactive magnetron co-sputtering at room temperature and nitrogen/oxygen reactive

atmosphere. After growth, the samples were annealed at 300°C and 400°C for 1 hr in a

nitrogen atmosphere. The thermic treatment improved the crystalline structure of the

ZnO:Ag,N thin films, the annealed films showed three well defined peaks at 31.62, 34.24,

and 36.12 degrees, that correspond to the (100), (002) and (101) planes of wurtzite structure

for hexagonal ZnO respectively. The electrical properties were explored by Hall Effect

measurement. After annealing treatment the films presented p-type conductivity with hole

concentration greater than 1016 cm-3

[ THF-492 ] post annealing influence on properties of In-

N codoped ZnO thin films

F. Avelar Muñoz 3 , J. J. Ortega ([email protected]) 3 , J. Ortiz Saavedra

3 , V. H. Méndez García 1 , C. Falcony 2 , J. J. Araiza 3

1 CIACyT, UASLP, San Luis Potosí, México 2 CINVESTAV, IPN, Distrito Federal, México.


DC reactive co-sputtered p-type ZnO:In-N thin films were deposited at room temperature

using a reactive atmosphere of nitrogen and oxygen at different concentrations. After growth,

the samples were annealed at 300°C for 1 hr in a nitrogen atmosphere. The crystalline

structure was determined by XRD, as deposited films were practically amorphous, however

after heat treatment the films showed the typical hexagonal structure of ZnO. As deposited

films presented n-type characteristics, however, the electrical conductivity showed a

transition from n-type to p type for the films treated at 300°C, in all cases the hole

concentrations are lesser than 1016 cm-3. The transparency of the films were gradually

reduced as the atomic percentages of nitrogen and indium were increased, concurrently, the

Tauc obtained band gap was shifted to lower energies.




459

[ THF-555 ] Photoconductivity of aluminium doped ZnO

thin films obtained by the sol-gel method

Cristhian Alejandro Mercado-Ornelas 2 , Juan Ortiz-Saavedra 2 , Jose de

Jésus Araiza-Ibarra 2 , Felipe Puch-Ceballos 2 , Leticia Pérez-Arrieta 2 ,

José Guadalupe Quiñones-Galván 1 , H. Tototzintle-Huitle


1 Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías,

Universidad de Guadalajara, Guadalajara, México. 2 Unidad Académica de Física, Universidad Autónoma de Zacatecas, Zacatecas, México.

ZnO materials are of great interest for their optical, structural, electrical and

photoconductivity properties and also by their chemical stability which are essential aspects

for many possible applications, e.g. as transparent electrodes and windows in solar cells, in

gas sensors, and as photocatalytic agents. In ZnO:Al, photoresponse show a slow conduction

decay process, wich is controlled by surface effects such as gas adsorption and desorption.

Consequently, the decay of photoconduction is strongly dependent on the ambient gas

conditions. In this work, we describe the room temperature photoconductivity of thin films

of aluminium doped zinc oxide prepared by the sol-gel technique on silica glass substrates.

The starting solutions were prepared using zinc acetate as precursor, diethylene glycol as

organic template, methanol as solvents, triethylamine as chelating agent and aluminium

nitrate as dopant. The Zn molar concentration of the solutions used to obtain the thin films

were 1.3 M. The content of aluminium in the precursor solution is refered as the atomic

porcentage with respect to Zinc. Here, we used [Al]/[Zn]= 1,3 ,5,7 ,9 % at. The films obtained

where thermally treated in air at 500°C. The samples were characterized by XRD, EDS, UV-

Vis and IR spectroscopies. Van Der Paw measurements were used to investigate the electrical

and photoelectrical properties in various ambient atmosphere. The dark conductivity of the

films decreased with decreasing film thickness while the conductivity under illumination was

almost constant and was in the range of 10-2 to 101 Scm irrespective of the film thickness.




460

TRIBOLOGY (TRB)

Chairman:

Joaquin Oseguera Peña (ITESM)

Sesión Oral

[ TRB-22 ] Mechanical and tribological performance of

red clay ceramic tiles coated with flay ash powders by

thermal spraying technique.

Gabriel Peña-Rodríguez ([email protected]) 1 , Jaime Dulce-Moreno 1 ,

Jessica Daza 2 , Silvia Orozco 2 , Fabio Vargas-Galvis 3

1 Department of Physics. Group GITEC Francisco de Paula Santander University 2 Industrial Engineering. Francisco de Paula Santander University

3 Research group pyrometallurgical and Materials (GIPIMME), University of Antioquia

The mechanical and tribological performance of red clay ceramic tiles uncoated and coated by oxy-

fuel thermal spraying process from flay ash powders was evaluated. The ceramic tile substrates were

manufactured by uniaxial pressing at 26.17 bar pressure, and sintered at 1100 °C. The coating

thickness was determined based on the number of projection-cycles oxyacetylene flame over

substrate. The structure was studied using X-ray diffraction (XRD, Bruker D8 Advance) and scanning

electron microscopy (SEM, FEI Quanta 650 FG); the mechanical resistance to bending and wear by

abrasion deep, were studied using NTC standards 4321-4 and 4321-6 respectively; adhesion was

measured using Elcometer equipment Type III according to ASTM D-4541-02 and the average

roughness (Ra) was found according to ASTM standard D7127-13, using the profilometer Mitutoyo

SJ 201. The surface morphology presented the heterogeneous molten or semi molten splats with good

adhesion, justifying increased mechanical resistance to bending and wear by abrasion deep.These

results contribute to the development of ceramic products with added value, to be used in various

technological applications.




461

[ TRB-51 ] Tribological evaluation of hydrogenated

DLC coating deposited on carbon steel

José Solis Romero ([email protected]) 1 , Oscar Hernández Gómez 1 , Luis

Tranquilino 1 , Víctor Augusto Castellanos Escamilla 1 , Oscar armando

Gómez Vargas 1

1 SEP/SES/TecNM/IT de Tlalnepantla. Av. Mario Colin S/N, Tlalnepantla de Baz, Edo. de

Méx. CP 54070

In oil and gas companies many components are subjected to wear and corrosive

environments. The development of protective coatings on these parts is of high interest to

preserve its structural integrity. The chemical stability of diamond-like carbon (DLC)

coatings seems to be good candidates for corrosion protection in addition to their wear

resistance for using in pipelines equipment, such as subsea check valves, pistons and pumps.

The aim of this study is to evaluate the tribological performances of a hydrogenated DLC

coating. The coating was deposited on API X65 carbon steel using plasma enhanced chemical

vapour deposition technology (PECVD). Characterization of the films was carried out by

means of Nano-indentation, surface roughness, calotest, Raman spectroscopy, atomic force

microscopy, and scanning electron microscopy. Tribological analysis was done in terms of

wear tests under continuous and reciprocating sliding with maximum initial Hertzian stress

of 150 and 400 MPa under dry condition. The Hydrogenated DLC film provided a good

improvement on the integrity against corrosion on carbon steel due to the positive results in

relation to wear tests.




462

[ TRB-125 ] Tribology of Nanocomposite coatings in

Methane Environment

Giovanni Ramirez ([email protected]) 1 , Osman L. Eryilmaz 1 , Osmary

Depablos 2 , Roberto Mirabal 2 , Yifeng Liao 1 , Sandra E. Rodil 2 , Ali

Erdemir 1

1 Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439, USA 2 Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico,

Mexico City, Mexico

Different nanocomoposite coatings based on metallic nitrides (V/Mo) and catalytically active

metals (Cu/Ni) were prepared using a high impulse magnetron sputtering (HIPIMS) system.

The content of the segregated phases of the nanocomposite films was optimized using the

power ratio between the different metallic targets during coating preparation. The coatings

were deposited on AISI 52100 steel substrates which were previously subjected to ion etching

using HIPIMS. The tribological tests were performed in a ball-on-disk test machine under

900 mBar of methane gas pressure. The coated pairs (ball and disk) were compared with the

uncoated pairs of 52100 steel. The nanocomposite coatings were able to reduce friction by

as much as 40% in comparison with the uncoated steel samples. Most importantly, the wear

of the nanocomposite surfaces was reduced dramatically to an unmeasurable level. The

chemical composition, structural morphology and microstructure of the coatings were

studied by X-ray photo electron spectroscopy, scanning electron microscopy, and X-ray

diffraction. The superior tribological performance of the nanocomposite coatings in methane

environment was studied using Confocal Raman in order to elucidate the chemical nature of

tribochemical interactions and hence the plausible mechanisms responsible for extraordinary

wear performance.




463

[ TRB-152 ] Tribological performance of 316L AND

316L TiN coated against uhmw pe and uhmw pe

mediacal grade for orthopaedic joint implants

Alejandro Peña Bautista ([email protected]) 1 , Joaquín Esteban

Oseguera Peña 2 , Dulce Viridiana Melo Máximo 1 , Rafael Carrera

Espinoza 1

1 Instituto Tecnológico y de Estudios Superiores de Monterrey, CEM 2 Instituto Tecnológico y de Estudios Superiores deMonterrey, CEM

An excellent tribological couple for orthopaedic joint implants preferably will include a

metallic component articulating as 316L against a polymer component ultra-high molecular

weight polyeltilene (UHMW PE). However, the accelerated wear of UHMW PE in bearing

surfaces produces debris principally and cause high wear and high coefficient friction. In

order to improve the performance of tribological biomaterials pair a PVD TiN coating was

deposited on 316L surface; in addition UHMW PE underwent treatment of gamma radiation

for transform it to medical grade. 316L, TiN, UHMW PE and UHMW PE medical grade

biomaterials were characterized (Ra, H, E, SEM); also thickness and XRD were characterized

for PVD TiN.

A series of three wear test were made on pin on disc tribometer considering the following

tribological pair of materials: 316L against UHMW PE; 316L against UHMW PE medical

grade; 316L PVD TiN coated against UHMW PE and 316L PVD TiN coated against UHMW

PE medical grade at wear conditions: 5, 10 and 15 N of applied load, 0.05 m/s of sliding

speed, 1000 m of sliding distance and distilled water lubricated condition. UHMW PE and

UHMW PE medical grade shows high wear meanwhile 316L and 316L PVD TiN coated

materials they almost did no wear (negligible).

Different values of wear rate and friction coefficient were obtained; considering 5, 10 and 15

N of applied loads, the best wear pair (lowest wear and friction coefficient) it was to 316L

against UHMW PE medical grade and the worse wear pair (highest wear and friction

coefficient) it was to 316L PVD TiN coated against UHMW PE medical grade.

Keywords: Wear, friction coefficient, PVD TiN coating, UHMW PE




464

[ TRB-227 ] Comparison of the tribological behavior of

an AISI 1538MV steel: surface laser quenching versus

conventional quenching & tempering treatment.

Rafael Carrera Espinoza ([email protected]) 2,5 , Ulises Figueroa

López ([email protected]) 3 , Alejandro Rojo Valerio 1 , Joaquin del Prado

Villasana 4

1 Centro de investigación de Mecatrónica Automotriz, ITESM Campus Toluca, Eduardo

Monroy Cárdenas 2000, San Antonio Buenavista, 50110 Toluca de Lerdo, Méx. 2 Escuela Nacional de Posgrado, ITESM Campus Estado de México, Carr. Lago de

Guadalupe Km. 3.5, Margarita Maza de Juárez, 52926 Atizapán de Zaragoza, Méx. 3 Ingeniería Mecánica y Mecatrónica y Escuela Nacional de Posgrado, ITESM Campus

Estado de México, Carr. Lago de Guadalupe Km. 3.5, Margarita Maza de Juárez, 52926

Atizapán de Zaragoza, Méx. 4 Investigación Desarrollo e Innovación, ITESM Campus Toluca, Eduardo Monroy

Cárdenas 2000, San Antonio Buenavista, 50110 Toluca de Lerdo, Méx. 5 Posgrado, ITSPR, Calle Luis Donaldo Colosio Murrieta S/N, Arroyo del Maíz, 93230

Poza Rica de Hidalgo, Ver.

This paper compares the tribological behavior of an AISI 1538MV steel that was heat treated

by two technologies: surface laser quenching and a conventional quenching and tempering

treatment. Sliding wear tests were carried out by the pin-on disc method. A 5 mm diameter

WC ball and 56.2 mm diameter and 5 mm thick disks were used as a tribo-pair. The worn

surfaces on the disks and the ball were evaluated by SEM and MO, respectively, for to

identify the wear mechanisms. The coefficient of friction (CoF) for the tribo-pair in the laser

quenched samples were slightly lower than the values obtained for the conventional treated

ones. A similar behavior was found for the wear rate. Laser quenching offers a similar

tribological performance than conventional quenching and tempering, and therefore, it is

possible to use one or other, depending on the application and the available technology.




465

[ TRB-556 ] Tribological Challenges in Micromachines

Esteban Broitman ([email protected]) 1

1 IFM, Linkoping University, SE58183 Linkoping, Sweden

Micromachines are mechanical devices with designed sizes in the range 100 nm to 100 µm,

and usually fabricated with semiconductor technologies to integrate mechanical components

with electronics on a single chip. Known also as MEMS (micro-electro-mechanical systems),

present industrial applications include accelerometers in automotive systems, inkjet printer

heads, game controllers, and rotation sensors for smartphones.

Most of commercial micromachines are designed as transducers for applications with no

contact or sliding: they are either sensors or actuators. Despite of niche industrial applications

with designs of more complex MEMS devices containing moving mechanical assemblies

(MEMS-MMA) like micromotors, gears and levers, the commercial production of these kind

of micromachines is inexistent. The main problem in micromachines is tribological: the

presence of stiction, high friction and wear between the small components. Adhesion at the

microscale is a consequence of van der Waals forces: electrostatic interactions between

surface dipoles and charges, as well as capillary phenomena and chemical forces. Friction

and wear are inevitable in mechanisms where components in contact have relative motion.

Friction become increasingly significant as the system size shrinks and it is a crucial factor

that determines not only efficiency but durability. Therefore, it becomes critical on the

microscale and is one of the fundamental limitations in the design of reliable micromotors,

microgenerators, and microengines. Lubrication for decreasing friction and wear in these

devices is difficult, because capillary forces created by confining liquids to small geometries

is in the same order of magnitude as actuation forces generated by micromachines. Therefore,

only solid or vapor-phase lubrication can be used. However, there are some applications like

stepper motors taking advantage of friction: with step sizes on the order of 10 to 100 nm, and

actuation forces in the milli-Newton scale, they could be used for positioning optical, data

storage, and medical applications.

This work focuses on the main tribological challenges of micromachines. The

characterization of multi-length-scale tribological phenomena will be reviewed. Basic silicon

mechanical and tribological properties and micromachining methods are reviewed. Solid

lubrication by depositing carbon-based coatings using thin film technology, and liquid

lubricants applied by vapor-phase lubrication are discussed. Potential improvements and

economic feasibility issues are also addressed.




466

Sesión Poster

[ TRB-9 ] TRIBOCORROSION BEHAVIOUR OF

Nb/NbN FILMS

Erika Ruiz ([email protected]) 1 , Wiliiam Aperador 1

1 School of Engineering, Universidad Militar Nueva Granada, Bogotá-Colombia

Niobium Nitride a coating has been studied for its superconducting properties, hardness, wear

resistance to corrosion; furthermore improve corrosion resistance and wear on the coated

steel surface. Regarding, its chemical properties is characterized by a high melting point and

low resistivity; with this study was performed the evaluating of the NbN thin films with an

intermediate layer of Nb on substrates of AISI 316LVM stainless steel, deposited by physical

vapor deposition technique in order to evaluate the effect of the bias voltage in the process

deposition, on the degradation rate, tribological properties and system triboelectrochemistry.

The tribological tests were performed with a bone pin and the corrosion resistance was

evaluated by testing the impedance electrochemical spectroscopy and Tafel polarization

curves, the electrolytic medium was Hank's solution. It was found that the electrochemical

parameters decrease with increasing bias voltage. The friction coefficient decreases in

comparison with the substrate and the wear in the synergistic system between mechanical

wear and electrochemical indicates that is lower when the evaluation is carried out in a

simulated biological fluid.




467

[ TRB-53 ] Electrochemical and tribological assessing of

WC-DLC coating deposited on API X65 carbon steel

José Solis Romero ([email protected]) 2 , Joaquín Oseguera Peña 1 ,

Víctor Augusto Castellanos Escamilla 2 , Miguel Angel Paredes Rueda 2 ,

Oscar Armando Gómez Vargas 2 , Rodolfo Velázquez Mancilla 2

1 Departamento de Mecatrónica, Instituto Tecnológico y de Estudios Superiores de

Monterrey, Campus Estado de México, Carretera al Lago de Guadalupe km 3.5, Atizapán

52926, México. 2 SEP/SES/TecNM/IT de Tlalnepantla, Div. de Posgrado. Av. Mario Colin S/N,

Tlalnepantla Edo. de Méx. CP 54070. México.

In many industrial applications components are submitted to wear and corrosive

environments. The development of protective coatings on these parts is of high interest to

preserve its structural integrity. The chemical stability of diamond-like carbon (DLC)

coatings seems to be a respectable candidate for corrosion and wear to protect pipelines

equipment, such as subsea check valves, pistons and pumps. The aim of this study is to

evaluate the electrochemical and tribological behaviour of WC-DLC coatings deposited on

API X65 carbon steel using plasma enhanced chemical vapour deposition technology. The

characterization of the film was carried out by means of Nano-indentation, surface roughness,

calotest, Raman spectroscopy, atomic force microscopy and scanning electron microscopy.

The applicability of these two types of coatings for corrosive protection was proved by means

of the electrochemical tests and electrochemical impedance. The tribological analysis were

done in terms of wear tests under reciprocating sliding with maximum initial Hertzian stress

of 150 and 400 MPa under dry and wet conditions. The electrochemical assesment was done

on the surface of DLC films before and after wear tests in order to verify if the corrosion

process of the carbon steel substrate into the wear defects could affect the adhesion of the

coating. Although no defects were observed on the hydrogenated DLC after wear tests

(contact pressure of 150 MPa), the electrochemical tests showed an increase on the anodic

current densities with these samples in relation to samples that were not subjected to wear

tests. It means that 150 MPa was sufficient to produce Nano defects on the hydrogenated

DLC surface and to exposure the carbon steel substrate to the corrosive solution. The

hydrogenated DLC film provided a good improvement on the integrity against corrosion on

carbon steel due to the positive results in relation to wear tests. Furthermore, it was evidenced

a protective barrier, a reduced pitting corrosion on the carbon steel bulk because of the same

OCPs, as it had high resistivity based on the lowest anodic current densities. In addition, the

results showed that the resistance of the film, applied over carbon steel had excellent

performance in situations where the equipment is subjected to conditions of wear and

corrosion acting together in saline environments.




468

[ TRB-54 ] Micro-abrasive wear of dynamic seals

Leonardo Israel Farfán-Cabrera ([email protected]) 1 , Ezequiel

Alberto Gallardo-Hernández 1

1 IPN, SEPI-ESIME Zacatenco, Grupo de Tribología, Col. Lindavista 07738, Mexico D. F.

Dynamic seals are devices utilized to prevent or limit fluid leakages in machinery. Abrasive

wear of seal lips is majorly produced by micro-particles (wear debris) deposited as

contaminants in the fluid involved. In this study, a TE 66 Micro-Scale Abrasion Tester was

used to simulate the micro-abrasive wear occurred. A Nitrile lip seal has been selected and

examined. The abrasive agent was made of distilled water and SiC micro-particles. Wear

results are showed at four different loads and various sliding distances. In addition, Scanning

Electron Microscopy and Laser Scanning Confocal Microscopy were used towards detecting

and obtaining the wear scar topographies and their measurements. In conclusion, this method

could be suitable to study the three-body abrasion occurred in elastomeric materials for

dynamic seal applications.




469

[ TRB-71 ] Modelling micro-scale abrasion of duplex-

treated steels

José Guadalupe Mata Maldonado ([email protected]) 1 ,

Rafael David Mercado Solís 1

1 Universidad Autónoma de Nuevo León

This paper presents details of a geometrical model of micro-scale abrasion of duplex-treated

steels based on the calotte-grinding test and Archard’s wear equation. In the computations,

the model calculates the individual wear coefficients of coating and substrate as a function

of either: (i) the outer calotte diameter and the coating thickness, (ii) the inner calotte diameter

and the coating thickness, or (iii) the outer diameter and the ratio between inner and outer

diameters. In practice the first two calculations are advantageous because coating thickness

is generally known beforehand, thus, the measurement of only one diameter is needed.

However, a better insight into the micro-abrasive wear process may be accounted for if the

third approach is used because it provides a clearer separation between the extents of wear

underwent by the coating and by the substrate. This is a particularly useful approach when

significant differences in wear coefficients for the coating and the substrate are expected. The

proposed model was validated by a series of calotte-grinding experiments using a 30 mm

diameter steel ball rotating against duplex-treated (ion nitrided + PVD coated) AISI H13 tool

steel, coated with TiN, CrN and TiAlN by arc evaporation. Since the experimentally obtained

results were in very close agreement with the predictions of the geometrical model, it is

concluded that the model is a very powerful tool for micro-abrasive wear predictions in

duplex-treated steels and it may be further extended to other coated systems.




470

[ TRB-369 ] Nanofrictional behavior of Y-Cr-O films

with amorphous, crystalline and textured

microstructures

J. J. Gervacio-Arciniega 2 , Francisco J. Flores-Ruiz

([email protected]) 2 , C. J. Diliegros-Godines 2 , E. Broitman 3 , C. I.

Enriquez-Flores 1 , F. J. Espinoza-Beltrán 1 , J. Siqueiros 2 , M. P. Cruz 2

1 CINVESTAV Unidad Querétaro, Lib. Norponiente 2000, Real de Juriquilla, 76230

Querétaro, Qro. México. 2 CNyN-UNAM, km. 107, Carretera Tijuana-Ensenada 22860, Ensenada, B.C., México. 3 Thin Film Physics Division, IFM, Linköping University, SE-58183 Linköping, Sweden

Differences in friction coefficient (µ) of magnetoelectric textured and polycrystalline YCrO3

and non-magnetoelectric Y-Cr-O amorphous films are analyzed. The friction coefficient was

evaluated by atomic force microscopy using a simple quantitative procedure where the

dependence of friction force with the applied load is obtained in only one topography image.

A simple code was developed with the MATLAB® software to analyze the experimental data.

The code includes a correction the hysteresis in the forward and backward directions. The

quantification of load exerted on the sample surface was obtained by finite element analysis

starting from experimental dynamic information. The result showed that polycrystalline films

have a friction coefficient (~0.1) similar to those with amorphous structure while the textured

films grown on epitaxial substrate has the highest µ (~0.5). From a viewpoint of industrial

application, where the recording of ferroelectric memories is mechanically achieved pressing

AFM tips against the surface, YCrO3 films grown on non-epitaxial substrate seem to be the

better candidates due to their lower µ.




471

[ TRB-470 ] Physical and tribological properties of

reactively co-sputtered Niobium Zirconium Nitride

K. C. Luna Sandoval 4 , J. J. Ortega ([email protected]) 4 , H. Tototzintle

Huitle 4 , J. G. Quiñones Galván 2 , C. Falcony 1 , R. Escobedo Galindo 3 ,

J.J. Araiza 4

1 CINVESTAV, IPN, Distrito Federal, México. 2 CUCEI, UDG, Jalisco, México. 3 ICMM, CSIC, Madrid, España


In this work are reported on the physical and tribological properties of reactively sputtered

niobium zirconium nitride deposited on steel sheets and crystalline (100) silicon wafers as

substrates using Nb and Zr targets. These films were grown using a fixed power to the Zr

target (70 W), but with a variable power to the Nb target. The chemical composition was

obtained from EDX measurements. X-ray diffraction revealed that a two-phase

nanocomposite material was formed. The nanocomposite consisted of nanocrystals of (Nb,

Zr)N, embedded in an amorphous matrix. The optical constants were measured using spectral

ellipsometry and were simulated using a Drude-Lorentz model. The hardness and elastic

modulus values were measured by nanoindentation and were correlated to the microstructure

of the films.




472

Science Divulgation (SCD)

Chairman:

Wilfrido Calleja (INAOE)

Sesión Oral

[ SCD-256 ] El método de valoración contingente en el

manejo de residuos peligrosos de la región Cuitzeo,

Michoacán

María Liliana Ávalos Rodríguez ([email protected]) 1 , Jorge

Víctor Alcaraz Vera 1

1 Universidad Michoacana de San Nicolás de Hidalgo

Los cambios en la producción y productividad del siglo XIX han dado la pauta para analizar

los efectos al ambiente y sociedad, uno de esos efectos ha sido la generación de residuos que

independientemente de sus características representan un peligro. Por ello diversos estudios

muestran que se puede valorar económicamente su manejo y generación; esta investigación

analiza estudios que han empleado dichos métodos, destacando que la mayoría de ellos

analizan la problemática de residuos urbanos (67%), el 4% abordan los residuos de manejo

especial y el 39% los residuos peligrosos. Se observa que los estudios consideraron la

valoración contingente, estudios hedónicos, costo de recreación, de beneficio, de viaje, de

reposición, de efectividad, mitigación, análisis y morbilidad. Las principales variables

observadas fueron los tipos y volúmenes de residuos, el factor riesgo, la peligrosidad, las

condiciones socioeconómicas y el manejo de residuos en función del cumplimiento de las

disposiciones legales en materia técnica y operativa. En materia de residuos peligrosos, los

estudios sugieren que se pueden valorar a través del método de valoración contingente que

pretende conocer la disponibilidad a pagar por que el manejo bajo parámetros de eficiencia

sanitaria, ambiental y económica. Como resultados preliminares de la aplicación del Método

de Valoración Contingente en la Región Cuitzeo, Michoacán mediante una encuesta a

generadores de residuos peligrosos, se observa que el 80% está dispuestos a pagar montos

que oscilan entre los $2.00 a los $4,000 pesos por gestiones y servicios técnicos, operativos

y jurídicos.




473

[ SCD-285 ] Hidrógeno, ¿energía del futuro?

Mario Fidel García Sánchez ([email protected]) 1

1 Unidad Profesional Interdisciplinaria de Ingeniería y Tecnologías Avanzadas, Instituto


El hidrógeno aparece en la actualidad como una de las fuentes de energía renovables, pero

se conoce muy poco sobre ella. Entre sus principales ventajas con respecto a otras energías

renovables está su posibilidad de generar energía de forma continua, independientemente de

las condiciones atmosféricas, con eficiencia superiores al 50 %. Pero aún existen varios

aspectos que deben ser mejorados para su implementación a gran escala. En esta plática se

expondrán de forma general las distintas etapas y problemáticas que tiene la transición a una

“economía del hidrógeno”; desde la obtención y almacenamiento de este compuesto, hasta

el diseño de celdas de combustible para su transformación en energía eléctrica. Se

comentarán los distintos tipos de celdas de combustible, haciendo énfasis en las llamadas de

celdas de estado sólido, y los aspectos científicos (materiales y tecnologías) en los que se está

investigando en cada caso. Entre estos aspectos ha crecido el interés en utilizar materiales

nanoestructurados, debido a los cambios en las propiedades físico-químicas que producen las

restricciones en su tamaño.

En esta presentación se exponen además algunos resultados obtenidos en el crecimiento de

algunos materiales nanoestructurados en películas delgadas para electrolitos y su posible

aplicación en celdas de combustible de temperatura intermedia (~ 600 °C). Los materiales

fueron obtenidos por la técnica de rocío pirolítico en su variante ultrasónica y se observó que

la disminución del tamaño de grano permite reducir la energía de activación del material y

aumenta la conductividad, que es uno de los objetivos fundamentales de las investigaciones

en el campo de las celdas de combustible.




474

[ SCD-385 ] Polímeros conductores: una alternativa

para fabricar dispositivos termoeléctricos

Cesia Guarneros Aguilar ([email protected]) 1

1 Catedrática CONACyT, CICATA-IPN Unidad Altamira, Carretera Tampico-Puerto

Industrial Altamira Km 14.5, Industrial Altamira, 89600, Altamira Tamaulipas, México

Actualmente, el problema de la energía ha atraído mayor atención ya que las fuentes de

energía fósiles convencionales algún día se agotarán, por lo que encontrar recursos

energéticos alternos es urgente. Mientras tanto, optimizar el consumo energético es un reto,

ya que del total de la energía producida sólo se utiliza el 34% y el 66% se pierde como calor

disipado. Este calor disipado es producto del trabajo de maquinaria, industrias, refinerías, gas

natural, plantas nucleares, estaciones de potencia y automóviles. Sin embargo, parte de esta

energía perdida puede convertirse en electricidad. En los últimos años los investigadores han

encontrado una nueva manera de aprovechar el calor disipado mediante dispositivos

termoeléctricos basados en el “fenómeno Seebeck”, es decir, son capaces de convertir el calor

en electricidad. Estos dispositivos se han fabricado de compuestos químicos basados en

elementos como el telurio, bismuto, antimonio, silicio, germanio y plomo, pero su

fabricación es costosa y no son amigables con el medio ambiente. Debido a esto, la mirada

se ha vuelto sobre materiales que pueden hacer este trabajo pero sin dañar al medio ambiente

y que su manufactura resulta barata. Algunos polímeros, por ejemplo polianilina, polypirrol

y politiofeno, tienen la capacidad de conducir corriente eléctrica y se han considerado para

fabricar dispositivos termoeléctricos. Estos materiales conocidos como polímeros

conductores tienen una estructura química no saturada lo que permite el flujo de electrones a

través de ellos de manera similar al flujo de electrones en los metales. El polímero polianilina

es el más investigado debido a que es fácil de sintetizar, tiene excelentes propiedades

eléctricas y es muy estable en el ambiente; estas características lo hace un buen candidato

para fabricar dispositivos. Hoy día ya se comercializan aparatos que utilizan materiales

termoeléctricos en su funcionamiento, por ejemplo los enfriadores portátiles, calentadores y

sensores de temperatura, sin embargo, se está trabajando en hacer a estos dispositivos más

eficientes y prácticos, pero sobre todo se espera que los polímeros conductores ayuden a

alcanzar el objetivo de recuperar energía.




475

[ SCD-439 ] Propuestas de la ciencia de materiales para

mitigar los efectos del calentamiento global*

M. Meléndez-Lira ([email protected]) 1

1 Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, México, DF 07000,

México

Los efectos del calentamiento global fueron predichos con bases científicas desde el siglo

XIX. El primer señalamiento se realizó en 1864 por John Tyndall al descubrir la opacidad

del dióxido de carbono a la radiación infrarroja. Actualmente, aun cuando es cada vez más

aceptado que las actividades humanas tienen una influencia determinante en el calentamiento

global, existen grandes inercias para modificar las actividades que contribuyen a este efecto

que pone en riesgo a la humanidad.

El sol ha sido la fuente primordial de energía de la tierra siendo el responsable de la aparición

y sustento de la vida. La adaptación de la naturaleza para aprovechar la energía solar tiene

una de sus máximas expresiones en el proceso de la fotosíntesis. Mediante la fotosíntesis, las

plantas acumulan energía vía la transformación del el dióxido de carbono en glucosa.

La fotosíntesis y los océanos actuaron durante muchos años como reguladores del dióxido

de carbono presente en la atmosfera. Sin embargo el crecimiento explosivo de la

humanidad ha generado un exceso de dióxido de carbón y como consecuencia el

calentamiento global al ser sobrepasados los reguladores naturales de dióxido de carbono.

En esta plática presentaremos en forma breve como la ciencia de materiales puede emplear

materiales diseñados para aprovechar el máximo la energía solar en dos formas:

1. Materiales fotovoltaicos que permiten producir energía renovable evitando la quema de

hidrocarburos.

2. Materiales que permiten realizar la fotolisis el agua y que acoplados con sistemas |carbono

presente en la atmosfera.

El éxito en la implementación masiva de estos sistemas constituiría un elemento de ayuda

para los procesos naturales de regulación del dióxido de carbono.

*: Trabajo financiado parcialmente por CONACyT.




476

[ SCD-457 ] Propuesta de Enseñanza Aprendizaje

Basado Prototipo Solar Generación de Energía

Experimental

Luiz Antonio Rasia ([email protected]) 2 , Juliana Maria Meotti 1

1 State Technical School July 25, Pedro Américo Street, 479, Ijuí, Brazil 2 Unijuí / DCEEng - Department of Science and Engineering, Sao Francisco Street, 501,

Ijuí, Brazil

En este trabajo, se propone la construcción de un prototipo de enseñanza para estimular el

interés de los estudiantes de secundaria y carreras técnicas en ingeniería por fuentes de

energía solar, en particular los sistemas fotovoltaicos. La planificación energética es un punto

estratégico para el desarrollo sostenible de un país. Esta propuesta busca que desde la escuela

los docentes y las nuevas generaciones estudien y profundicen sobre el tema de energías

renovables, principalmente la solar, y sean parte activa en la solución de la problemática

energética y ambiental que enfrenta nuestro planeta. Esto ha motivado la investigación de

fuentes limpias de energía como los sistemas solares y plantas de energía eólica, ya que son

de bajo impacto ambiental renovable. La opción para la generación de energía solar

fotovoltaica es debido a la simplicidad de la obtención de este tipo de energía generada por

conversión directa de luz en electricidad mediante el efecto fotovoltaico. En esta propuesta

se enseñan los conceptos básicos de energía, energías renovables y sus aplicaciones,

destacando la importancia de la energía solar para la vida en la Tierra. En las últimas décadas

la ciencia y la tecnología se ha convertido en los grandes símbolos de los avances en el mundo

y en los últimos años, muchas de las áreas de pregrado prácticamente desaparecido de las

ofrendas regulares de las instituciones educativas del interior de Brasil y dio lugar a las áreas

de la ingeniería. En este contexto, los jóvenes que también tenían algún interés en el

seguimiento de las áreas de la enseñanza comenzaron a migrar a las áreas de técnica, creando

una nueva demanda de afiliación.




477

[ SCD-471 ] El futuro deformable, flexible y elástico para

la electrónica

Roberto Ambrosio Lazaro ([email protected]) 1

1 Facultad de ciencias de la Electrónica, BUAP, Edif. 109B. Ciudad Universitaria. 18 Sur y

Avenida San Claudio. San Manuel. Puebla, Pue.

La electrónica flexible es la puerta de entrada a una nueva generación de dispositivos

electrónicos tales como: pantallas, teléfonos , implantes cerebrales , miembros artificiales ,

celdas solares y otros dispositivos sin límites que se benefician de la capacidad de doblar ,

enrollar y cambiar de forma. Los grupos de investigación en el mundo han desarrollado

pantallas súper-ligeras y flexibles que podrían se usadas como pantallas de papel pintado en

la pared o que podrían funcionar como iluminación, electrónica vestible, entre otras

aplicaciones. Sin embargo el problema es encontrar la manera de hacerlo.

El investigador John Rogers de la universidad de Illinois en Urban–Champaign ha descrito

que la electrónica del futuro deberá ser elástica y suave. Debido a que los dispositivos

basados en esta nueva tecnología deben de tener la capacidad de estirarse, girar , ser

deformables en formas curvilíneas, permitiendo así aplicaciones que serían imposibles de

lograr mediante el uso de la electrónica de hoy en día basada en circuitos y dispositivos

mecánicamente rígidos. Los grupos de investigación en el campo de la microelectrónica

creen que el próximo hito es desarrollar sistemas electrónicos que eviten la naturaleza rígida,

frágil, y plana que se tiene actualmente, para permitir nuevos modos de uso. Se ha

desarrollado investigación en este campo desde hace mas de 15 años, primeramente por el

desarrollo de pantallas de gran área y flexibles. Pero el alcance se ha expandido hacia

posibilidades en dispositivos biomédicos que se integren íntimamente con el cuerpo humano

y en los diseños de productos que explotan las formas curvilínea, ergonómica, o diseños de

inspiración biológica. ¿Te has imaginado un tatuaje electrónico en la piel? ¿Para que crees

que sirva?

En este trabajo se presenta un enfoque hacia el desarrollo de la tecnología para la electrónica

deformable y flexible, hasta llegar a aplicaciones de electrónica vestible. Se describen el

desarrollo de nuevos materiales electrónicos, como, semiconductores orgánicos que se

pueden flexionar, los conductores de materiales compuestos que se pueden estirar. Métodos

alternativos de obtención de los materiales inorgánicos semiconductores, hasta su aplicación

en dispositivos. Se discuten las aplicaciones mas recientes en áreas de la biomedicina como

el monitoreo intra- cardíaco y neuronal. Así como diodos emisores de luz orgánicos y

sensores para robótica entre otros.




478

[ SCD-528 ] De Micro a Nano y lo que sigue, Mas allá de

la Ley de Moore

Alfonso Torres ([email protected]) 1

1 LI-MEMS, INAOE, Puebla, Mexico, [email protected]

Desde principio de los años 70´s, la fortaleza de la industria de semiconductores ha sido su

habilidad de seguir la Ley de Moore, siendo esta el motor de un círculo virtuoso: a través del

escalamiento, se obtiene una mejor relación funcionamiento/costo, que resulta en un

crecimiento exponencial del mercado de semiconductores. La industria electrónica encara

ahora una nueva tendencia, “More than Moore” (MtM), mediante la que nuevo valor se

agrega a dispositivos a través de la incorporación de funcionalidades que no necesariamente

escalan de acuerdo a la Ley de Moore. Se tratará de explicar que es MtM y que oportunidades

ofrece esta nueva perspectiva de desarrollo de la industria electrónica y lo que en el

LIMEMS-INAOE realizamos dentro de esta área de investigación.

[ SCD-529 ] Electronica y microsistemas; ciencia y

tecnologia de lo pequeño en méxico

Wilfrido Calleja ([email protected]) 1

1 LI-MEMS INAOE, Puebla, Mexico, [email protected]

La ciencia y la tecnología en general, con su uso generan un impacto positivo en favor de la

Economía y de la Sociedad de quienes las desarrollan. En su vertiente relacionada con la

Electrónica moderna, representa una oportunidad de desarrollo para nuestro país.

La Microelectrónica es una tecnología que se ha desarrollado para la fabricación de circuitos

integrados (chips) utilizando como materia prima un tipo especial de materiales conocidos

como semiconductores. En la industria Electrónica transnacional, los chips se utilizan como

componente principal en la fabricación de sistemas electrónicos tales como teléfonos

celulares, TV Inteligente, equipos de audio y una amplia variedad de sistemas

computarizados de gran utilidad en áreas tales como ingeniería Biomédica,

telecomunicaciones, industria automotriz, etc.

La Microelectrónica es una rama de la Ingeniería Eléctrica, cuyo producto principal es el

microprocesador, un chip bastante complejo en su funcionamiento, en el cual su elemento




479

básico es el transistor. En esta tecnología el prefijo “Micro” se refiere a que las dimensiones

físicas del transistor, son del orden del micrómetro ó micra. Los términos microelectrónica y

microchip siguen vigentes aún cuando en la actualidad los transistores tienden hacia el

tamaño nanométrico.

La Microelectrónica ha basado su desarrollo principalmente en los avances de la Ciencia de

Materiales, para producir nuevos materiales semiconductores y dieléctricos que posibilitan

la fabricación de sensores de amplio espectro y modernos actuadores. La tecnología de

microelectrónica establece los fundamentos para el desarrollo de nuevas tecnologías que

integran circuitos convencionales con sensores y actuadores, tal como los Sistemas

MicroElectroMecánicos (MEMS, Microsistemas).

En el contexto de Economía, se ha identificado que los Recursos Humanos especializados en

la Ciencia de Materiales y Microelectrónica, son un bloque fundamental para el avance de la

Tecnología y que la industria Electrónica los demanda como un factor clave para construir

sus plantas de investigación, desarrollo tecnológico y producción industrial. En tanto este

requisito está vigente en todas las áreas de la Ciencia y Tecnología; es particularmente

relevante para la Nanotecnología, Nanoelectrónica y Microsistemas; que siendo tecnologías

de vanguardia, además influyen en todas las áreas de la Investigación Científica. Estudios de

prospección realizados en los Estados Unidos de Norteamérica, comunidad europea y en los

principales países de Asia, arrojan como resultado la necesidad de técnicos especializados en

Nanotecnología y Microelectrónica, del orden de cientos de miles de especialistas. Por lo

anterior, si se atiende esta tendencia tecnológica mundial, el establecimiento de un sistema

educativo especializado en México será esencial para que sea posible desarrollar

Nanotecnología, Microelectrónica y Nanoelectrónica Nacional, tecnologías que darán lugar

al desarrollo innovador de nuevos materiales, procesos de manufactura y sistemas

electrónicos modernos.

En esta conferencia se aborda la importancia de la Microelectrónica en México como

tecnología nodriza para el desarrollo de los Microsistemas, Nanoelectrónica y

Nanotecnología, y su potencial influencia en el sistema educativo y la Economía de nuestro

país.




480

[ SCD-536 ] ¿Los objetos tienen color?

Juana Medina Márquez ([email protected]) 1

1 INAOE, Laboratorio de Visión por Computadora (LVC), Puebla, Mexico,

[email protected]

Si pregunto al azar, en la calle o en el trabajo, a una persona ¿de qué color son las hojas de los árboles?, ¿de qué color es la sangre?, ¿de qué color son las manzanas?,

¿de qué color es la rosa que está en tu jardín?, ¿de qué color es tu carro?..., puedo asegurar

casi al cien por ciento que sus respuestas serán verde, roja, amarilla, azul. Estamos tan

acostumbrados a hablar de colores, que damos por hecho tales afirmaciones, sin detenernos

a pensar si nuestras respuestas son acertadas.

Les propongo que antes de responder, nos formulemos esta pregunta: ¿los objetos tienen

color? Si no están seguros de lo que responderán, los invito a que juntos nos adentremos a

este mundo maravilloso de la interacción entre la luz y la materia, y vayamos poco a poco

descubriendo y contestando ésta y muchas preguntas más que estoy segura irán formulándose

y replanteándose en sus mentes.

Podemos responder a esta pregunta haciendo uso del espectro visible de la luz, dividiéndolo

en tres tercios (la idea principal surge del articulo “Understanding the arithmetic of color”,

que escribí en colaboración con Sandra Balderas y Carlos Zúñiga, Revista Mexicana de

Física 2015), lo que nos ayudará a predecir los nuevos colores obtenidos al mezclar luces

(mezcla aditiva) o pinturas (mezcla sustractiva), sin olvidar que para ello es necesaria una

fuente de luz que emita e incida sobre los objetos o el entorno, y por supuesto, tener un par

de ojos sanos, que de manera natural y automática percibirán y detectarán los resultados.

Esto sucede ya que al hablar de color involucramos tanto acciones físicas, que producen un

estímulo en forma de luz, como acciones de detección e interpretación de esos estímulos, que

llegan a nuestros ojos y se transmiten al cerebro, el cual procesa la información, indicándonos

que algo se percibe como verde, rojo, azul, amarillo, etcétera, además de darnos información

de las características físicas de los objetos en relación a su textura, forma o bordes, entre otros

parámetros.




481

[ SCD-557 ] MOEMS para formación de imágenes y

procesamiento de información

Francisco J Renero ([email protected]) 1

1 INAOE, Optica, [email protected]

Micro-Optical-Electrical-Mechanical-Systems (MOEMS) es la fabricación de sistemas

óptico-mecánicos con técnicas de circuitos eléctricos integrados. Se presentará la técnica de

fabricación de micro-depresiones en silicio, así como diseños ópticos fundamentados en esta

técnica. Por otro lado, se analizarán los sistemas ópticos basados en ojos de animales, en

particular los llamados ojos compuestos de aposición y superposición. Se mostrarán diseños

ópticos para formación de imágenes y para procesamiento de información.

[ SCD-568 ] La energía del futuro

Juan Luis Peña Chapa ([email protected]) 1

1 Applied Physics Department, CINVESTAV-IPN, Apdo. Postal 73, Mérida, Yucatán,

97310, México

Es difícil creer que nuestra principal fuente de energía ha ce 200 años era la madera

y despues petroleo. Ahora tenemos una gran cantidad de fuentes de energía para elegir,

incluyendo una gama cada vez mayor de tecnologías de energía s renovable s .

Pero ¿Q ue nos depara el futuro? ¿Cómo podemos mantener el suministro de energía a una

población cada vez mayor? ¿Cuánto va a costar? ¿Y qué impacto tendrán las opciones

energéticas que tomamos sobre nuestras condiciones de vida y de nuestro

planeta? Actualmente hay cinco megatendencias globales, incluyendo; crecimiento de la

población, el cambio climático, las innovaciones tecnológicas, mejores niveles de vida y el

desarrollo económico . Así que, ¿cómo estas tendencias marcan nuestro futuro? La

humanidad siempre ha usado energia para poder desarrollarse, sin energía no podemos hacer

nada. Sin embargo, en los dos últimos siglos la fuente de energía que mas hemos consumido

ha sido el peteóleo Ahora la pregunta que debemos de hacernos es ¿Toda esta energía de

donde proviene? Aun mas profunda, la vida en la Tierra es producto de un proceso energético

que ha tardado millones de años ¿Como se origino la vida en la tierra? Las primera pregunta,

en forma general se podrían contestar que el Sol es la fuente fundamental de energía en la

Tierra. La segunda , aun no se conoce con exactitud ; pero lo que si se sabe, es que los

primeros seres vivos que fueron policelulares sobrevivieron gracias a que fueron capaces de

aprovechar la energía que el Sol les proporcionaba: energía luminosa o




482

calorífica. Tambien con la energía de los volcanes, los rayos de las tormentas eléctricas y la

luz ultravioleta desencadenando reacciones químicas de los gases simple presentes hace

millones de años en la atmosfera de la Tierra para generar compuestos orgánicos simples,

con los que se construiría la vida.El ultimo antepasado universal surgió “vivió” en la tierra

hacen unos 3,500 Después siguió todo un proceso evolutivo primigenio. Estas células,

adoptaron la luz solar como fuente de energía, hacen unos 3.000 millones años, ya algo

similar a la actual fotosintesis (que es la conversión realizada por las plantas de energía

luminosa a energía química) se había desarrollado. Esto hizo que la energía solar fuera

disponible no sólo para los grupos de células vivas que se alimentan así mismas, sino que

también para los que se nutrían de ellos (actualmente los seres humanos y los animales en

general). La fotosíntesis consume la energía de la luz solar, produce carbohidratos ricos en

energía quimica que obtenemos cuando los ingerimos. El tema final a tratar sera como

la fotosintesis es la fuenta de energia mas importante en la tierra y sera si logramos copiarla

la energia del futuro.

This work has been supported by CONACYT-SENER (México) under project CeMIE-Sol

207450/P25




483

AUTHOR LIST

Abundiz Noemi ALD-206, ALD-276

Aca Víctor MEM-534

Aca López Viridiana THF-263

Acero Gutiérrez Ana Karen THF-348

Acevedo Dávila J.L. THF-90

Acosta Dwight THF-118, THF-119, NSN-117

Acosta-Silva Yuliana de Jesús NSN-541, THF-298

Aguila Lopez Josefina NSN-97, NSN-95

Aguilar Guillermo NSN-493

Aguilar Frutis Miguel Ángel CHM-219, CHM-224, SGE-249, THF-328

Aguilar García Antonio RWE-154

Aguilar Hernandez Jorge Ricardo SEM-189

Aguilar Hernández Jorge R. NSN-148, SEM-139, SEM-184, THF-430

Aguilera-Vázquez L. SEM-98

Aguirre Tostado Francisco Servando ALD-443, BIO-571, THF-530

Agustín Serrano R. NSN-171, NSN-89

Alarcón-Flores G. SGE-249

Alarcon Flores Gilberto CHM-219, CHM-224

Albor Aguilera Lourdes SEM-99

Alcántara Iniesta Salvador SEM-191, SEM-192, CHM-414, PPP-425

Alcaraz Vera Jorge Víctor SCD-256

Alcántara Llanas Perla Itzel MEM-509

Alcántara Quintana Luz E BIO-539

Aldana Vázquez Araceli NSN-507

Aleman Miguel MEM-151, SEM-153

Aleman-Arce Miguel A. THF-308

Allan Herrera Eusebio CHM-175

Almaguer Flores Argelia BIO-284

Almaral Sanchez Jorge Luis BIO-353, SEM-164, SEM-165

Alonso-Núñez Gabriel NSN-302

Alonzo-Medina G.M. BIO-514

Altamirano-Juárez Delia Cristina AMC-561, BIO-559

Altuzar Victor BIO-80

Alvarado Salvador PPP-527

Alvarado Flores José Juan SEM-252

Alvarado Noguez Margarita Lizeth PPP-179

Alvarado Pulido Joaquín CHM-414, SGE-229

Alvarado Pulido José Joaquín SEM-370

Alvarado Rivera Josefina AMC-88, AMC-228, AMC-214

Alvarado Gil J.J. PPP-407, PPP-467




484

Alvarado Noguez Margarita Lizbeth PPP-570

Álvarez Ana Laura BIO-320

Álvarez Arturo Maldonado THF-83

Álvarez Juan Manuel MEM-534

Álvarez Montaño V.E. SGE-29

Álvarez Bayona Ramón Alexis NSN-60

Álvarez Gómez Karin Monserrat SGE-229

Amador María de la Luz Olvera THF-82, THF-83

Amaya Delgado Lorena RWE-126, RWE-17

Ambrosio Roberto RWE-281

Ambrosio Hernández Javier R BIO-539

Ambrosio Lázaro Roberto Carlos MEM-455, SCD-471, RWE-496

Andraca Adame José Alberto CHM-310, SEM-232, CHM-301

Andrade Tomas Héctor de Jesús BIO-559

Anzures Daniel BIO-283

Aperador William TRB-9, AMC-37

Araiza Ibarra Jose de Jésus AMC-465, THF-555, THF-492, THF-466, THF-483, TRB-470

Aranda García Rubén Jonatan NSN-388

Araujo Pérez Daniel de Jesús THF-254

Arellano Arreola Víctor CHM-447

Argibay Nicolas THF-344

Arias Ortiz Julio Omar SEM-168

Arias Cerón José Saúl SEM-377, SEM-550, SEM-333

Ariza Calderón Hernando CHM-334

Arizpe Chavez Humberto NSN-60

Armenta Márquez Ana Karen MEM-38

Arredondo León Yesenia ACS-160

Arredondo Rea Susana Paola BIO-353,, SEM-164

Arrieta Castañeda Alma Mireya SGE-177

Arrizon Gaviño Javier Placido RWE-17

Arvizu Rodríguez L.E. SEM-98

Atondo Rubio Gelacio THF-190, THF-328, RWE-17, NSN-545, RWE-126

Atzin Mondragon C. THF-380, SEM-379

Avelar Muñoz F. THF-492

Ávila Alvarado Yuliana Elizabeth ACS-346, ACS-222

Ávila Gaxiola Jorge Carlos RWE-17, RWE-126

Ávila Gaxiola María Elisa Evangelina RWE-126, RWE-17

Avilés García R.G THF-146

Ayala A.M NSN-70

Ayala Torres Marco Alberto NSN-325

Ayón Arturo NSN-39

Águila-Almanza Eva Álvarez E. AMC-228, BIO-515, ACS-452

Álvarez Laura BIO-132




485

Álvarez Mario Enrique AMC-214

Álvarez Ramos Mario Enrique AMC-88, NSN-410

Ángel Huerta Froylán SEM-199

Ávalos Rodríguez María Liliana SCD-256

Balderas López José Abraham PPP-506, PPP-361, PPP-384, PPP-378

Bandala Sánchez Manuel MEM-509

Barajas Aguilar Aarón Hernán SEM-111, SEM-96, SEM-387

Barajas Carrillo M. M. THF-405

Barón Miranda Javier Armando SEM-340, SEM-331

Barón Miranda A. SEM-98

Barboza Flores Marcelino CHM-24

Barceinas Sánchez José Dolores Óscar SEM-321

Barrera Serafín THF-508

Barrientos Sotelo Víctor Rodrigo PPP-87

Bartolo Pérez César MEM-481

Bartolo Pérez Pascual THF-105, NSN-94

Basurto Rafael THF-462

Bautista Hernández Alejandro ACS-92, ACS-186

Becerril Marcelino THF-286

Becerril Marcelino SEM-65

Behar Moni NSN-93

Benavides Parra Juan Carlos PPP-169

Benítez Lara Alfredo THF-48

Benítez Alejandro PPP-87

Benítez Serrano J. Carlos BIO-183

Berman Mendoza Dainet THF-25

Bernal Rodolfo SGE-29, THF-25

Bernal Correa R. THF-311

Berrout Ramos Laura Adriana SEM-109

Blanco Alonso Oscar NSN-144

Brachetti Sibaja Silvia Beatriz THF-396, THF-460

Brandy Garza Jorge Alberto SEM-321

Bravo González Edith NSN-490, SEM-494, BIO-502, SEM-504

Bravo García Yolanda Elinor SEM-232, CHM-310, PPP-233

Bravo Sanchez Mariela CHM-268

Briones Edgar SEM-416, CHM-415

Briones Joel SEM-416, CHM-415

Briones Torres José Alberto SEM-100

Briseño Rodríguez Rodolfo MEM-509

Britto Hurtado Ricardo Andrés NSN-60

Briz López Eva Marina AMC-392

Broitman Esteban TRB-369, TRB-556

Budini Nicolás PPP-503




486

Buendía Lozada Enrique CHM-265

Cabañas Moreno José Gerardo CHM-363

Caballero Briones Felipe CHM-175, SEM-331, SEM-340, SEM-321, SEM-168, SEM-98

Caballero Contreras Ivan CHM-258

Cabello Alvarado Christian NSN-94

Cabral Larquier Eva María AMC-523. AMC-525

Cabrera Carlos I. SEM-121

Cabrera Humberto PPP-527

Cabrera Arenas Víctor RWE-424

Cabrera Guerrero Edgar NSN-50

Cabrera Llanos Agustín Ignacio CHM-12, CHM-11

Cabrera-German Dagoberto CHM-436, CHM-215, CHM-343, CHM-288

Caicedo Julio Cesar AMC-37

Calderón Antonio PPP-30

Calderón Jeniffer PPP-30

Calderón Arenas José Antonio PPP-260

Calixto Ma. Estela RWE-257

Calleja Arriaga Wilfrido MEM-534, SEM-313, MEM-220, SCD-529

Calva Chavarría Primo Alberto PPP-361, PPP-384

Calzadilla Amaya Octavio SEM-168, SEM-250, SEM-480

Camacho Alcántar María del Carmen THF-25

Camacho García José Humberto ACS-186, NSN-185

Camacho López Marco Antonio NSN-493

Camacho López Miguel Ángel NSN-493, CHM-349

Camarillo Sifuentes Arezbith RWE-239

Campero Antonio SGE-277

Campos E. SEM-381, NSN-364, SEM-406

Campos Arias Martha Patricia CHM-219

Campos Gaxiola José de Jesús SEM-164

Campos González Enrique BIO-213, RWE-204, NSN-499, SEM-138, THF-140

Campos Silva Ivan Enrique AMC-335

Campos Arias M. P. SGE-249

Camps Enrique THF-123, SEM-138, THF-140, PPP-120

Canchola Flores Víctor Manuel CHM-312

Cano Casas Rogelio PPP-87

Canto Santana Gabriel Iván ACS-482

Cardona Dagoberto SEM-540

Cardona Ramírez D. SEM-553, SEM-548

Carmona Rodríguez Julián Javier THF-84

Carmona Tellez Salvador CHM-219

Carréon Alvarez Alejandra NSN-144

Carrera Espinoza Rafael TRB-152, TRB-227

Carrillo Flores Diana María NSN-531, NSN-532




487

Carrillo López Jesús RWE-496, THF-48

Carrillo Castillo Amanda SEM-109

Carro Gastélum E. SGE-249

Casallas Moreno Yenny Lucero SEM-540, SEM-553, SEM-548, NSN-108

Casasanero Meléndez Arlette SEM-139

Castañeda Contreras Jesús THF-306

Castañeda Galván Adrián A. SEM-367

Castañeda García Didier NSN-97

Castañeda Guzmán Rosalba PPP-188

Castañeda Priego Ramón ACS-297, ACS-290

Castañeda Valderrama Rocío NSN-144

Castaño V.M. SGE-29

Castaño Víctor Manuel THF-25

Castaños Luis THF-190

Castelán Figueroa Juan Manuel NSN-432

Castelán Acevedo Cesar CHM-251

Castellanos Escamilla Víctor Augusto TRB-53, TRB-51

Castillón Felipe ALD-206, ALD-276

Castillo Baldivia Edith Guadalupe NSN-69

Castillo Zaragoza Enrique CHM-560

Castillo Alvarado Fray de Landa SEM-184, RWE-317, RWE-72

Castillo Ojeda Roberto Saul SEM-196

Castrejón Sánchez V.H. SEM-138

Castro Beltrán Andrés BIO-353

Castro Rodríguez Román Ernesto THF-463

Castro Arellano José Javier NSN-209

Catarino Rafael THF-7

Ceballos Sánchez Oscar ALD-351, THF-359

Cedeño Bernal Enrique PPP-485

Cedeño Garcidueñas Verónica Janette THF-105

Ceja Andrade Israel NSN-144

Cerdeira Altuzarra Antonio SEM-370

Cervantes José Luis ALD-444

Cervantes Contreras Mario SEM-510

Cervantes Flores Maribel BIO-127

Cervantes Juárez Erika NSN-499

Cervantes López José Luis ACS-55

Cervantes Martínez Jesús RWE-17

Cervantes Alvarez F. PPP-467, PPP-407

Chalé Lara Fabio Felipe SEM-331, SEM-340, SEM-168, CHM-175, SEM-321, SEM-98

Chan y Díaz Enrique Josué THF-463

Chandross Michael THF-344

Chavarria Rubio J.A. CHM-368




488

Chavelas González Andrea Pamela THF-371, SEM-379, THF-380

Chávez Portillo Melissa SEM-397

Chávez Rivas Fernando NSN-209

Chávez cinco maría Yolanda BIO-278

Chávez Castillo M. R. ACS-142

Chávez Chávez Arturo SEM-403

Chávez Urbiola Iker Rodrigo SEM-342

Chico Vázquez Martha CHM-309

Chigo Anota Ernesto ACS-452

Chipatecua Godoy Yuri Lizbeth ALD-351, ALD-383, THF-359

Chiu Zarate Roger THF-306

Chuc Palacios V.M. PPP-467

Cifuentes Ángel PPP-527

Cifuentes Ángel PPP-527

Cisneros Magaña María Remedios NSN-205

Clark Blythe THF-344

Clegg Miriam L. ALD-58

Cohen Estelle NSN-337

Colín Orozco Elena BIO-390, BIO-391

Conde Gallardo Agustín MEM-79

Contreras Oscar E. SEM-336

Contreras López Oscar CHM-24

Contreras Navarrete José de Jesús NSN-193, NSN-205

Contreras Puente Gerardo Silverio SEM-139, RWE-204, SEM-99, SEM-189

Contreras Solorio David Armando RWE-338, RWE-239, RWE-240

Contreras Turrubiartes Maria Magdalena Montsserrat ALD-401, ALD-400, ALD-412

Contreras Gallegos Eder PPP-169

Contreras Puente Gerardo RWE-85, SEM-184, THF-430

Contreras Rascón Jorge I. SEM-199, SEM-200, SEM-198

Contreras Solorio David A. SEM-121

Corona Rivera Miguel Ángel THF-238

Corral Higuera Ramón SEM-165, BIO-353

Correa Pacheco Zormy Nacary PPP-294, PPP-295, PPP-558

Cortés Ortiz Emma BIO-128

Cortés Sandoval Gabriela BIO-10, BIO-6

Cortés López Silvia NSN-207

Cortés Rodríguez Edith RWE-562

Cortés Carreón Francisco SEM-99

Cortes Mestizo Irving Eduardo NSN-522, SEM-416, CHM-415

Cortez Valadez Manuel NSN-60, SGE-441

Cosme Ismael SEM-216

Cota Martínez Isis María AMC-517

Couto Moreira Rodrigo MEM-449




489

Cruz Guillermo J BIO-320, BIO-132

Cruz M. P. TRB-369

Cruz Cruz Guillermo J. BIO-73, BIO-390, BIO-391, BIO-75, BIO-74

Cruz Enríquez Adriana SEM-165

Cruz Gómez Marco Antono CHM-265

Cruz González Nadia NSN-319, BIO-316

Cruz Hernández Esteban NSN-399, SEM-519, ACS-297, ACS-290, NSN-393, SEM-408,

NSN-409

Cruz Irisson Miguel ACS-365

Cruz Orea Alfredo PPP-179, PPP-570, PPP-169, PPP-87

Cruz Ortiz Brenda R. AMC-329

Cruz Vázquez Catalina THF-25, SGE-29

Cruz Zaragoza Epifanio NSN-155

Cuevas Figueroa José Luis ACS-365

Cuevas Sánchez Melisa PPP-378

Curiel Mario ALD-275, ALD-274, ALD-271, ALD-270

Daza Jessica TRB-22

Díaz Zavala Nancy Patricia BIO-283

Dávila Pintle José Antonio CHM-310

Díaz Tomas, THF-327

Díaz Arango Gerardo Ulises MEM-542

Díaz Becerril Tomás SEM-242

Díaz Marcos Jordi SEM-331

Díaz Monge Fernando THF-211

Díaz Reyes Joel NSN-97

Díaz Torres Elizabeth PPP-179

Díaz Ballote L. PPP-467

Díaz Guillén J.A. THF-90

Díaz Guillén J.C. THF-90, THF-90

Díaz Monroy Gilberto Gamaliel SEM-540, SEM-553

Díaz Reyes Joel SEM-198, SEM-196, SEM-199, SEM-200

Díaz Ruiz Araceli BIO-320, BIO-132

De Anda Francisco SEM-67

De Anda Salazar Francisco Javier NSN-69

De la Cruz García M. A. NSN-171

De la Cruz Terrazas Edna Carina SEM-262

De la Cruz Hernández Wencel CHM-215, CHM-436, THF-359, CHM-288

De la Hidalga Javier SEM-313

De la Luz Tlapaya Verónica SGE-569

De la Mora M.B. PPP-188

De la Torre Saenz Karina Patricia AMC-517

De Lázaro Gasca Karla BIO-515

De Luna Bugallo Andrés NSN-337, ALD-351, ALD-383




490

De Melo Claudia NSN-93

De Melo Pereira Osvaldo THF-430, RWE-85, NSN-93, RWE-85

De Moure Flores Francisco RWE-204, THF-430, NSN-440, NSN-442, NSN-431

Del Ángel-López Deyanira THF-460

Del Muro Arteaga Edmundo Emmanuel NSN-43

Del Oso Acevedo José Alfredo SEM-99

Del Prado Villasana Joaquin TRB-227

Del Río De Santiago Antonio NSN-409

Del Real López Alicia BIO-103

Del Rio De Santiago Antonio NSN-399

Delgado Macui Raúl BIO-434

Depablos Rivera Osmary, THF-157, TRB-125

Díaz Tomas NSN-78, SEM-398,

Díaz Becerril Tomas NSN-50

Díaz Cano Aarón Israel BIO-502, SEM-504, NSN-490, SEM-494

Díaz de León Zapata Ramón SEM-544

Díaz Moreno Carlos Alejandro AMC-305

Díaz Ramos I.E. ACS-92

Díaz Rodríguez Tania Gabriela ACS-418

Díaz Vallejo Nathalia AMC-37

Díaz Alonso Daniela MEM-534

Díaz Reyes Joel RWE-562, SEM-333

Diez Pérez Ismael SEM-331, SEM-98

Diliegros Godines C. J. TRB-369

Domínguez A. SEM-218

Domínguez David ALD-275, ALD-271, ALD-270, ALD-274

Domínguez Domínguez Ranferi CHM-224

Domínguez Herrera José Ernesto CHM-560

Domínguez Crespo Miguel Antonio THF-396, THF-460, SEM-262

Domínguez Herrera José Ernesto AMC-561

Dominguez David ALD-276, ALD-206

Domínguez J. BIO-514

Domínguez Jiménez Miguel Ángel CHM-237

Domínguez Jiménez Miguel A. SEM-191, SEM-192

Domínguez Mendoza Blanca Eda NSN-432

Domratcheva Lvova Lada NSN-205, NSN-193, BIO-235

Donohue Cornejo Alejandro BIO-127

Dorantes Rosales Héctor Javier CHM-224

Doria Andrade J. THF-311

Driver Stephen M. ALD-58

Droopad Ravindranath CHM-415

Dugger Michael THF-344

Dulce Moreno Jaime TRB-22




491

Duran Ledezma Ángel Adalberto CHM-347

Durán Navarro Alejandro NSN-193

Durón Torres S. M. SEM-218

Durruthy Rodriguez María Dolores AMC-269

Eguía Eguía Sandra Irene NSN-389

Elizalde E. A. SEM-218

Elizalde Galindo José Trinidad NSN-531, NSN-532, SGE-441, AMC-523, AMC-525, ALD-

253, ALD-412, AMC-517, AMC-484

Elizalde Peña Eduardo Arturo NSN-158, SGE-210, NSN-122

Enciso Agustín SEM-121

Enciso Muñoz Agustín RWE-240

Enríquez Carrejo J.L. SEM-406

Enriquez Flores C. I. TRB-369

Erdemir Ali TRB-125

Eryilmaz Osman L. TRB-125

Escamilla Díaz Tonatiuh AMC-81

Escobar Alarcón Luis NSN-170, THF-462, CHM-486

Escobar Barrios Vladimir Alonso BIO-6, BIO-10

Escobedo Galindo R. TRB-470

Escobedo Morales Alejandro NSN-185, NSN-388

Escobedo Alcaraz R. THF-380, SEM-379

Escobedo Galindo R. THF-466

Escobosa Echavarría Arturo NSN-411, NSN-108

Escorza Chávez Juan Ignacio PPP-295, PPP-558

Esparza Alegría Enrique PPP-188

Esparza Hernández A. THF-466

Espino Cortés Fermín Pascual BIO-174

Espino Valencia Jaime SEM-252

Espinosa Nestor ACS-505

Espinosa Cristóbal León Francisco BIO-127

Espinosa Faller Francisco Javier SEM-331, SEM-168, SEM-182

Espinosa Vega Leticia Ithsmel NSN-518, CHM-415, SEM-519

Espinoza Figueroa José Angel NSN-409, SEM-408

Espinoza Beltrán F. J. TRB-369

Esquilano Rendón Diego BIO-136

Esquiliano Rendón Ricardo BIO-129

Esquivel Escalante Karen SEM-218, SGE-210, NSN-158, NSN-122

Estrada Horacio MEM-526, THF-308

Estrada Cruz Juan Francisco del Rosario ACS-55

Estrada Moreno Ivan Alziri BIO-116

Estrella Rodríguez Julio César CHM-175

Eugenio López Eric NSN-445, NSN-522

Fabela Sanchez Omar Felipe BIO-213, BIO-320, BIO-132




492

Falcony Guajardo Ciro NSN-76, CHM-224, THF-84, CHM-219, THF-483, TRB-470,

THF-492, THF-466

Farfán Cabrera Leonardo Israel TRB-54

Farías Mario ALD-271, ALD-274, ALD-270, ALD-275

Farías Sánchez Juan Carlos BIO-235

Farías José Rurik SGE-441, AMC-484, AMC-517

Farías Mario H. ALD-206, ALD-276

Farías Mancilla José Rurik NSN-531, AMC-523, AMC-525, ALD-412, ALD-253, SEM-406

Fernández Vladimir THF-40

Fernández Muñoz J.L. SEM-250, RWE-244

Fernández Osorio Ana Leticia SGE-413

Fernández Carlos THF-190

Fernández Madrigal Arturo NSN-114

Fernández Muñoz José Luis SEM-480, THF-238, NSN-364

Ferraz Johnny NSN-93

Fierro Ruiz Cesar David AMC-525, AMC-523

Figueroa López Ulises TRB-227

Flandre Denis SEM-370

Flores Acosta Mario NSN-60

Flores Cordero D. A. NSN-108, SEM-548

Flores Cuautle José de Jesús Agustín PPP-169, PPP-169

Flores Francisco ACS-505Flores González Mario Alberto SEM-196

Flores Gracia José Fransisco CHM-237, SEM-192, THF-263

Flores Juan Jorge Carmen THF-84

Flores Morales C. NSN-366

Flores Ortega Ana Cecilia RWE-240

Flores Ramírez Nelly NSN-193, NSN-205, BIO-236, BIO-235

Flores Rodríguez María del Carmen THF-211

Flores Ruiz Francisco J. TRB-369

Flores S. Cesar A. SGE-360

Flores Sánchez María Guadalupe BIO-129

Fonseca García Abril BIO-284, BIO-284

Fragoso Pérez Erika BIO-137

Fragoso Soriano Rogelio SEM-232

Fuentes García Jesús Antonio NSN-97, NSN-95

Furlan Humber MEM-449

Gabbi Renan THF-472

Galeazzi Isasmendi Reina SEM-242

Galicia Hernández José Mario ACS-289

Galindo Mentle Margarita MEM-220

Gallardo Hernández Salvador NSN-409, SEM-408, NSN-108, SEM-548, SEM-553,

SEM-406, NSN-364, SEM-540

Gallardo Hernández Ezequiel Alberto TRB-54




493

Galvan Arellano Miguel SEM-196, SEM-200, SEM-199, SEM-198

Galván Elizabeth THF-286

Galván Martínez Donald Homero THF-105, ACS-55

Gama Ortega Edgar Eduardo NSN-193

García Amaya Iveth Viridiana AMC-88

García Cruz María de la Luz MEM-477

García Fernández Tupak Ernesto PPP-188, PPP-375, PPP-255, NSN-382

García Godofredo THF-327, SEM-336, SEM-398, NSN-78

García González Leandro THF-254, NSN-193, NSN-205, BIO-235, SEM-49, NSN-39

García Gutiérrez Rafael THF-105, SEM-336, CHM-24

García Hipólito Manuel NSN-76, NSN-155, THF-190, THF-328, CHM-219

García Jaramillo E. AMC-465

García José Alegandro PPP-503

García Lozano Rodolfo SEM-153

García M. Antonieta SGE-360

García Payán Iván THF-190

García Peña Nidia CHM-268

García Ramírez Eliseo SEM-408, ALD-497

García Ramírez Emma Vianey NSN-512, AMC-484

García Rosales Genoveva BIO-75

García Rocha Miguel CHM-347

García Ruiz Diana Litzajaya NSN-193

García Salgado Godofredo THF-48, SEM-242, NSN-50

García Sánchez Mario Fidel THF-286, AMC-292, SCD-285

García Sánchez Miguel Ángel SGE-177

García Segundo Crescencio PPP-201

García Sotelo A.R. NSN-364, SEM-406, SEM-379, SEM-381, THF-380, THF-371

García Toral Dolores ACS-64

García Vargas Norma Angélica PPP-384

García Zaleta David Salvador CHM-259, ALD-383

Garza Gómez A. THF-90

Garza Hernández Raquel THF-530

Gelvez Lizarazo Oscar Mauricio BIO-474

Gennaro Ana María BIO-417

Geremia Marina MEM-266, MEM-449

Gervacio-Arciniega J. J. TRB-369

Gil Felix MEM-534

Giorcelli Mauro BIO-284

Giraldo-Daza H.A. CHM-368, CHM-368

Gnecco Enrique ACS-345

Godínez Salcedo Jesús Gilberto THF-348

Godínez Fernández Rafael BIO-135, BIO-136, BIO-147

Gómez Aguilar Ramón SEM-367, NSN-155




494

Gómez Diego CHM-339

Gómez Barojas Estela CHM-237, THF-263, BIO-183

Gómez Jiménez Lidia Ma. BIO-74, BIO-75, BIO-73

Gómez María Elena THF-203, NSN-124

Gómez Montoya Diego Fernando CHM-516, CHM-368

Gómez Miranda M. CHM-187

Gómez Romero Ricardo SGE-569

Gómez Rosas G. THF-405, SEM-446

Gómez Soberon José Manuel BIO-353

Gómez Sosa Gustavo CHM-288, CHM-259, CHM-447, ALD-351, ALD-383, CHM-436,

CHM-215, CHM-343, CHM-268

Gómez Vargas Oscar armando TRB-53, TRB-51

Gómez Yáñez Carlos AMC-341, AMC-479, BIO-174

González Arceo Ana Paulina MEM-509

González Calderón Luis E. BIO-180

González De la Cruz Gerardo SEM-162, PPP-233, CHM-310, SEM-232

González De la Torre E. A. SEM-446, SEM-403

González Díaz Víctor MEM-455

González Escobedo Gustavo NSN-185

González Fernández José Vulfrano SEM-544

González Hernández Andrés THF-460, THF-460

González Melchor Minerva BIO-332

González Palacios Cuauhtémoc BIO-390

González Pérez Raquel BIO-129

González Prieto Dalia Itzel CHM-175

González Rivera Yadira A. NSN-499, THF-140

González Salgado Francisco BIO-73, BIO-75, BIO-74

González Torres Maribel BIO-75, BIO-73, BIO-74

González Torres Maykel BIO-101, SGE-102, BIO-128, BIO-103

González Velázquez Jorge Luis CHM-224

González Zavala Fernando THF-462, CHM-486

Gorbatchev Andrei Yu. NSN-69

Granda Gutiérrez E.E. THF-90

Granada Ramírez Daladier Alonso SEM-377

Granados Martínez Francisco Gabriel NSN-205, NSN-193

Gross Katherine THF-203, CHM-334

Guadarrama R. Mariely SGE-360

Guarachi Solano Jonathan Félix PPP-260

Guarneros Aguilar Cesia PPP-503, SCD-385, SEM-262

Guerrero Castellanos Fermi MEM-455

Guerrero Contreras Jesus SEM-340

Guerrero Sánchez Jonathan ACS-374

Guiñones Galván J. G. SEM-446




495

Guillén Cervantes Ángel NSN-389, NSN-411

Guirado López Ricardo NSN-518

Gullian Klanian Mariel SEM-168

Gurevich Yuri G. SEM-13, SEM-14, SEM-15, SEM-16, RWE-20

Gutiérrez Amador María del Pilar NSN-437

Gutiérrez Enríquez Raúl SGE-177

Gutiérrez Fuentes Rubén CHM-349

Gutiérrez Garcia Carmen Judith NSN-193

Gutiérrez Garcia Xinah Herón BIO-131

Gutiérrez Hernández Manuel NSN-409

Gutiérrez Juárez Gerardo PPP-201

Gutiérrez Muñoz Monserrat RWE-66

Gutiérrez Z-B Karla RWE-85, THF-430

Guzman Martinez Carlos NSN-122, NSN-158

Guzmán C. SEM-218

Guzmán Mendoza José NSN-76

Hammes Graciane MEM-266, THF-472

Hamui Leon RWE-52

Haro Poniatowski Emmanuel CHM-486, NSN-170, THF-462

Heiras Jesús AMC-305

Heredia Jimenez Aurelio MEM-455

Hernández Andrade Juan Manuel BIO-23

Hernández Armando MEM-534

Hernández Arriaga Heber ALD-412, ALD-497

Hernandez Beteta Elias Emilio NSN-432

Hernández Castillo Isabel RWE-562

Hernandez Cocoletzi Gregorio ACS-374, ACS-394, ACS-395, ACS-289, ACS-222, ACS-

330, ACS-482

Hernandez Cocoletzi Heriberto BIO-515, ACS-452

Hernández Como Norberto MEM-151, SEM-153

Hernández Cuevas Francisco SEM-153, MEM-151, THF-308

Hernández David ACS-505

Hernandez De la Luz David SEM-245, CHM-237

Hernandez Espinosa Miguel Angel SGE-229

Hernández Francisco THF-118, THF-119

Hernández Geraldine NSN-124

Hernández Gómez Óscar TRB-51

Hernández Gordillo Armin SGE-277

Hernández Gutiérrez Carlos Alberto SEM-540, SEM-553, SEM-548, NSN-411

Hernández Hernández Arturo NSN-437, NSN-440, NSN-442, NSN-431, SEM-379, SEM-

406, NSN-108, NSN-364, THF-380, THF-371

Hernández Hernández Luis Alberto NSN-440, NSN-442, THF-430, NSN-431, SEM-379,

THF-380, THF-371




496

Hernández Hidalgo Bárbara CHM-251

Hernández Julián NSN-39

Hernández L. Roberto T. CHM-251, CHM-258

Hernández Landaverde Martín Adelaido SEM-111, SEM-96, SEM-387, SEM-172, AMC-

329

Hernández Luis M. SEM-121

Hernández Márquez Jesús Alfredo ALD-412, SGE-441

Hernández Martínez Luis MEM-38, MEM-542

Hernández Martínez Tzeitel BIO-278

Hernández Montero William W. SEM-313

Hernández Olguín C. E. RWE-72

Hernández Paredes Javier NSN-410

Hernández Paz Juan Francisco SGE-441, ALD-253

Hernández Pérez Isaías NSN-209

Hernández Pérez María De los Ángeles SEM-189, SEM-184, NSN-148, SEM-139

Hernández R. SEM-218

Hernández Ramírez Luis Mariano THF-105

Hernández Rodríguez Eric Noé RWE-567, RWE-244, SEM-480

Hernández Rosas Francisco PPP-87

Hernández Rosas Juan PPP-87

Hernández Santiago Erick Esaú SEM-168

Hernández Tecorralco J. ACS-142

Hernández Torres Julián THF-254, SEM-49

Herrera Celis José Luis THF-247, THF-208, BIO-474, CHM-447, CHM-259, ALD-383,

CHM-343, CHM-436, CHM-288, CHM-268, CHM-215

Herrera Gómez Alberto CHM-350, THF-359, ALD-351, CHM-447, CHM-259, ALD-383,

CHM-343, CHM-436, CHM-288, CHM-268, CHM-215

Herrera Hernández Héctor THF-254

Herrera May Agustín leobardo MEM-220

Herrera Ordóñez Jorge THF-508

Herrera Pérez José Luis SEM-333, SEM-377, SEM-550, NSN-95

Herrera Suárez Hernán Javier ACS-26

Hincapie Bedoya J. CHM-368

Hoy Benítez Juan Argel SEM-182

Huerta Blanca BIO-101

Huerta Figueroa Daniel Enrique CHM-167

Huerta García Tizoc Fernando NSN-282

Huerta Rosas José Fernando NSN-95

Huerta Ruelas Jorge-Adalberto CHM-215

Hurtado Castañeda Delia María SEM-377, SEM-550

Hurtado Macias Abel AMC-305

Ibarra Delgado Alejandro THF-190

Irwin Chuck SEM-96, SEM-111




497

Islas-Arteaga Nancy Cecilia BIO-147, BIO-131

Itzmoyotl Toxqui Adrián SEM-313, THF-208, MEM-534

Izrailev Mikhailovich Felix NSN-181

Jaime Fonseca Mónica Rosalía CHM-309

Jaramillo Torres Claudia RWE-204

Jaramillo Vigueras D. NSN-366, CHM-301

Jasso Jasso M. F. AMC-459

Jayaraman Vinoth Kumar THF-82, THF-83

Jiménez Córdova Karina del Carmen SGE-569

Jiménez Flores Steffanie PPP-425

Jiménez González Antonio Esteban PPP-425, CHM-414

Jiménez Hernández Víctor SEM-153

Jiménez León Jesús MEM-542

Jiménez Macías P.R. NSN-364

Jiménez Maira PPP-30

Jiménez Pérez Abimael SEM-109

Jiménez Pérez José Luis PPP-294, NSN-97, PPP-558, PPP-295

Jiménez Sandoval Sergio Joaquín SEM-387, SEM-111, SEM-172, SEM-96, SEM-138,

THF-140, SEM-98, NSN-302, NSN-499, AMC-329

Jiménez Vázquez Josué BIO-231

Jiménez Vivanco María del Rayo THF-327

Juárez Arellano Erick Adrián CHM-560

Juárez García José Manuel CHM-363, CHM-301

Juárez Héctor PPP-503, THF-327

Juárez Ignacio MEM-534

Juárez López Guillermo THF-84

Juárez Morales Luis Angel ACS-452

Juárez Morán Luis Alberto RWE-562, SEM-200

Juárez Nahuatlato Raúl SEM-398

Juárez Santiesteban Héctor BIO-417, NSN-50, ACS-418, SEM-397

Juárez Torres José Ángel NSN-95

Kamaraj Sathish Kumar SEM-340

Kar Swastik NSN-337

Kilchytzka Valeriya SEM-370

King David A. ALD-58

Koropecki Roberto Roman BIO-417

Kosarev Andrey RWE-314, SEM-216, SEM-322

Kudriavtsev Yuriy NSN-411

Lara Velázquez Ismael SEM-544

Lara Hernández Gemima PPP-169

Lara Romero Javier NSN-302

Lara Sánchez A. NSN-364




498

Lartundo-Rojas Luis SEM-106

Lashkevych Igor SEM-16

López Barrera J. Antonio PPP-107

López Calzada Gabriel SEM-96, SEM-111, BIO-103, SEM-172, SEM-387

López Cruz Elias RWE-257

Lopez Cuellar Enrique Manuel THF-47

López Gamboa Genaro PPP-295, PPP-294

López Gayou Valentín THF-247, NSN-432, BIO-434

López Huerta Francisco MEM-220

Lopez Javier ALD-275, ALD-271, ALD-274, ALD-270

Lopez Jorge AMC-305

López Lazcano Carlos Augusto SEM-165, SEM-164

López López Alexis Esteban AMC-479

López López Azucena PPP-570

López López Máximo NSN-409, SEM-408, SEM-553, NSN-108, NSN-411, SEM-540, THF-

430, NSN-399, SEM-548

López Luna Edgar ALD-401, ALD-412, ALD-400, ALD-497

López Medina Javier A. ALD-206, ALD-276

López Rubio Juan Antonio SGE-210

López Omar ALD-489, ALD-373

Lopez Oyama Ana Bertha SEM-262

López Roberto NSN-279

López Tabares J.P. CHM-368

López Tinoco Julián NSN-302

López Urías Florentino NSN-144

López Valentín SEM-398

León Valiente Xairo BIO-417

León Nataret Yosemik Arjuna BIO-502, SEM-504, NSN-490, SEM-494

Leos Mendez Hugo ALD-412, ALD-253

Lezama Pacheco Juan SEM-182

Liao Yifeng TRB-125

limón Morín Adriana MEM-455

Linares Aranda Mónico MEM-38

Liu Fangze NSN-337

Londoño Restrepo Sandra Milena BIO-456, BIO-454

Lopera Wilson NSN-124, THF-203

Loyola Rodríguez Juan Pablo BIO-6, BIO-10

Lozada Morales Rosendo L. AMC-88, NSN-499, THF-140, AMC-228, SEM-138, AMC-214

Lozano Ayerim CHM-41

Lozano Ramírez Tomás THF-460

Luebbert Larios Octavio ALD-443

Luis Alberto Mendoza De la Rosa AMC-329




499

Luna Alberto ACS-505

Luna Arias Juan Pedro SEM-377

Luna Flores Adán SEM-287, SEM-192, SEM-226, SEM-226

Luna Guzmán José Antonio CHM-219, SGE-249

Luna López José Alberto RWE-496, CHM-237, NSN-388, THF-48, SEM-192, SEM-191,

THF-263

Luna Palacios Yryx Yanet NSN-493

Luna Sandoval K. C. TRB-470

Luna Torres Erika THF-254

Luo Feng ACS-345

Macías J.D. PPP-467, PPP-407

Machorro Roberto ALD-275, ALD-271, ALD-270, ALD-274, ALD-276, ALD-206

Maciel Alfredo THF-303

Madrigal Melchor Jesús SEM-61, SEM-62, NSN-304

Magaña Carlos THF-118, THF-119

Magdaleno López Coraquetzali BIO-68

Makarov Nykolay NSN-181

Maldonado A. NSN-171

Maldonado Altamirano Patricia SEM-184

Maldonado Saavedra Octavio CHM-560

Maldonado Saavedra Octavio BIO-559

Mandru Andrada-Oana ACS-374

Mani Gonzalez Pierre Giovanni SGE-441, ALD-400, AMC-525, ALD-412, ALD-253, NSN-

532, SEM-406, AMC-484, AMC-517, ALD-497

Mansanares A.M. PPP-498

Mansurova Svetlana SEM-216

Manzanares Martínez María Betsabé AMC-214

Marañón Ruiz Virginia Francisca THF-306

Marín Ernesto PPP-527

Marín Moares Ernesto PPP-485

Marín Serrano Andrés PPP-361

Marcial Fernando NSN-39

Marel Monroy Betsabee NSN-442

Mari Soucase Bernabe RWE-257

Márquez González Óscar CHM-175

Martínez Ara Luis Arturo SEM-184, SEM-189

Martínez Castañón Gabriel Alejandro BIO-127,CHM-243, BIO-86

Martínez Cienfuegos Iván BIO-390

Martinez de la Cruz Azael THF-47

Martínez De León Jimena NSN-382

Martínez De León Mármol Jimena PPP-255

Martínez Falomir Gibran Guadalupe SEM-164, SEM-165




500

Martínez Flores Francisco BIO-134

Martinez G. BIO-514

Martínez García Nereyda Elizabeth SEM-340

Martínez Guerra Eduardo ALD-497, ALD-443, ALD-448, THF-530, BIO-571, ALD-444

Martínez González Kelly PPP-485

Martinez Guzman Carlos SGE-210

Martínez Hernández Ana Luara BIO-116

Martinez Javier ACS-505

Martínez Jesús ALD-271, ALD-274, ALD-270, ALD-275, ALD-276, ALD-206

Martínez José de Jesús RWE-281

Martínez Juan Antonio SEM-49

Martínez Juárez Javier SEM-226, SEM-287

Martínez Landeros Víctor Hugo THF-508

Martínez Luévanos Antonia AMC-329

Martínez Martínez Rafael THF-84

Martínez Martha Shaday SGE-102

Martínez Mateo Hiram Enrique RWE-314

Martínez Martínez Rita Elizabeth BIO-6, BIO-10

Martínez Pérez Lilia PPP-378, THF-264, THF-261

Martínez Puente Marcelo BIO-571

Martínez Rodríguez Pánfilo Raymundo BIO-6

Martínez Trinidad José AMC-335

Martínez Veliz Isaac NSN-399

Mata Maldonado José Guadalupe TRB-71

Mata Salazar Julio Heriberto CHM-350, CHM-215, CHM-436, CHM-343

Mathew Xavier PPP-503, THF-143, SEM-397

Mathews Nini Rose THF-113, RWE-154, NSN-70, THF-146, THF-143

Matsumoto Yasuhiro BIO-212, THF-82, BIO-213

May Pat A. BIO-514

Mazón Martínez Artemisa PPP-375, PPP-375

Mazón Montijo D. A. SEM-376

Márquez Beltrán César BIO-332

Márquez Buendía Verónica SEM-198

Márquez González Oscar Aarón SEM-168, SEM-340

Márquez Herrera Alfredo THF-238

Márquez Herrera Ciro Eliseo PPP-188

Meas Vong Yunny RWE-66. SEM-106

Medina Echavarría R. THF-311

Medina Márquez Juana SCD-536

Medina Llamas V. L. AMC-459

Medina Torres L. BIO-132

Medina Torres Luis BIO-320

Mejía Caballero Ivvone AMC-335




501

Mejía García Concepción NSN-325, SEM-553

Mejía Elsi NSN-117

Mejía Israel SEM-153

Meléndez Lira Miguel Ángel BIO-316, THF-380, SCD-439, SEM-379, NSN-431, NSN-442,

NSN-440, BIO-80, THF-371, NSN-319, NSN-364, SEM-381, SEM-406

Meléndrez Manuel ALD-448

Melchor Martínez María del Rosario ACS-64

Melendrez Amaviza Rodrigo CHM-24

Melo Máximo Dulce Viridiana TRB-152

Melo Piquive Catalina CHM-546

Melo Quintero J.J. CHM-368

Mena Angel NSN-78

Méndez Blas Antonio RWE-257

Méndez Camacho Reyna ACS-297, NSN-393, ACS-290

Méndez García Víctor Hugo NSN-445, NSN-522, CHM-415, SEM-416, NSN-409, SEM-

408, NSN-393, SEM-519, THF-492, NSN-399

Méndez Guadalupe BIO-101

Méndez Hernández Maritza SEM-226

Méndez López Arturo NSN-541, THF-298

Mendoza Álvarez Julio Gregorio SEM-333, PPP-233, SEM-232, CHM-310, SEM-377,

SEM-550

Mendoza Barrera Claudia BIO-80

Mendoza González Daniel BIO-174

Mendoza Martínez Ana María BIO-116, BIO-283

Mendoza Pérez Rogelio SEM-99

Mendoza Salvador MEM-151

Mendoza Serrato César Gustavo AMC-479, AMC-341, AMC-392, AMC-473

Meneses Juárez Efrain BIO-332

Meneses Meneses Maricela CHM-237

Meotti Juliana Maria SCD-457

Meraz Davila Susana THF-296

Mercado Aguilar Eduardo NSN-114

Mercado Solís Rafael David TRB-71

Mercado Ornelas Cristhian Alejandro THF-555

Meriuts Andrey SEM-14

Mertínez Mancilla Carmen AMC-473

Meza C.A THF-146

Meza Montes Lilia SEM-245, ACS-142

Michournyi Viatcheslav A. SEM-67

Millan Malo Beatriz BIO-454

Mimila Arroyo Jaime SEM-19, SEM-18, SEM-149

Mirabal Rojas Roberto THF-157 TRB-125

Miranda Durán Álvaro ACS-365




502

Miranda Meléndez Paulina Guadalupe BIO-86

Mis Fernández Ricardo RWE-567, RWE-244

Mishurnyi, Viatcheslav A. NSN-69

Mitani Nakanishi Yoshito CHM-363

Molar Velázquez Gabriela CHM-288, ALD-383, CHM-215, CHM-436

Molina Reyes Joel ALD-423, THF-421, NSN-419, ALD-422, ALD-489, ALD-373, THF-

429, ALD-435, ALD-497

Molina Valdovinos Sergio NSN-43

Mondragón Lozano Rodrigo BIO-73, BIO-74

Mondragón Rodrigo BIO-132, BIO-320

Mondragón Sánchez María de Lourdes NSN-193, NSN-205, NSN-366, CHM-301

Monfil Leyva Karim RWE-496

Monjarás Ávila Ana Josefina CHM-243

Monroy B. Marel RWE-52, NSN-108

Monroy Peláez Betsabée Marel NSN-437, AMC-292, RWE-438

Montañéz Delgado Alejandro SEM-172

Montes Gutiérrez Jorge CHM-24

Montes García Pedro AMC-561

Montiel Gonzalez Gustavo NSN-45

Montiel Gonzalez Zeuz THF-359, ALD-351, ALD-383, CHM-447

Mora Alvarado D.A. NSN-366, CHM-301

Mora González Miguel THF-306

Mora Hernández Ariam MEM-79

Mora Herrera David ACS-130

Morales Acevedo Arturo NSN-541

Morales Corona Juan BIO-391, BIO-213, BIO-390, BIO-212, BIO-173, BIO-129, PPP-107,

BIO-147, BIO-128, BIO-134, BIO-137, BIO-135, BIO-131, BIO-136, BIO-132

Morales de la Garza Leonardo ALD-58

Morales Francisco THF-327

Morales Gallardo M.V NSN-70

Morales Guadarrama Axayacatl BIO-132

Morales Juan BIO-320

Morales Marissa THF-303

Morales Méndez José Guadalupe NSN-170

Morales Ramírez Ángel de Jesús THF-348

Morales Ricardez E. SEM-250

Morales Ruiz Crisóforo SEM-242

Morales Sánchez Marco Antonio NSN-225, NSN-171, NSN-89

Morales Vanegas Jessica PPP-558

Morán Lázaro Juan Pablo NSN-144

Moreno Corella Gemma NSN-410

Moreno Coria Luis Armando CHM-414

Moreno Hernandez Juan Carlos ACS-186




503

Moreno Moreno Mario MEM-455, SEM-192, MEM-534, RWE-281, SEM-191

Moreno Rodriguez J. Albino BIO-183

Moroles Crisóforo SEM-398

Mourtazov Khassan THF-508

Muñiz Soria Jesús ACS-418

Muñoz Aguirre Narcizo THF-261, THF-264, CHM-307, CHM-312

Muñoz Aguirre Severino BIO-80

Muñoz Arenas Ligia Catalina SEM-226

Muñoz Arroyo R. THF-90

Muñoz Ramírez M. C. CHM-458

Muñoz Zurita Ana Luz RWE-496

Muhl Stephen THF-123, PPP-120

Mullapudi Gouri Syamala Rao SGE-248

Munguia Jacobo MEM-151

Murias Dulce RWE-281

Murillo Eduardo ALD-275, ALD-271, ALD-270, ALD-274

Mustre de León José SEM-182

NAIR M. T. S. SEM-376

NAIR P. K. SEM-376

Navarro Chavéz Oracio ACS-160

Negrete-Martinez Cynthia-Iveth CHM-215, CHM-343

Netzahual Lopantzi Angel BIO-434

Niño Martínez Nereyda BIO-86

Niño de Rivera Luis MEM-534

Nieto Gabriela THF-327, SEM-398

Nieto Caballero Gabriela NSN-50

Nieto Navarro José ALD-401

Ocón Trejo S. F. THF-483

Ojeda Durán Esteban RWE-496

Olaya Flórez Jhon Jairo THF-44, THF-359

Olayo González Ma. Guadalupe BIO-75, BIO-74, BIO-390, BIO-73, BIO-391, BIO-132,

BIO-320

Olayo González Roberto BIO-173, BIO-213, BIO-212, BIO-147, BIO-132, BIO-320, BIO-

128, BIO-136, BIO-134, BIO-180, BIO-137, BIO-135, BIO-131, BIO-129

Olayo Valles Roberto BIO-137, BIO-128, PPP-107, BIO-180

Olguín Daniel ACS-26

Olivares Cortez José Luis THF-47

Olvera Rodríguez José Alberto Isidoro NSN-122

Orduña Díaz Abdu BIO-434, THF-247, THF-208, BIO-474

Orduño Apodaca José Ramón BIO-353

Ornelas Gutiérrez Carlos NSN-532, NSN-531

Orozco Silvia TRB-22

Ortega Amaya Rebeca BIO-213, BIO-212




504

Ortega Cervantes Gerardo SEM-367, NSN-163, NSN-325

Ortega J. J. THF-492, THF-466, TRB-470, THF-483, SEM-519

Ortega López Mauricio BIO-173, BIO-213, BIO-212, NSN-541

Ortega Sigala J. J. AMC-459

Ortiz Frade Luis Antonio NSN-158

Ortiz Guzmán Margarito AMC-561

Ortiz Landeros José AMC-511, AMC-473, AMC-392, AMC-341, AMC-479

Ortiz Lopez Jaime NSN-163

Ortiz Morales Alejandro NSN-155

Ortiz Saavedra Juan THF-555, CHM-458, THF-492

Oseguera Peña Joaquín Esteban TRB-152, TRB-53

Osorio de la Rosa Edith BIO-417

Osorio Alcántara Karla M. BIO-183

Ospina Ocampo Carlos Alberto SEM-322

Ovalle Oscar AMC-511

Pacheco Alcalá Sadott SGE-102

Pacio Abraham PPP-503

Pacio Castillo Mauricio BIO-417, NSN-50, ACS-418, SEM-397

Pacio Mauricio THF-327, SEM-398, PPP-503

Padilla Flores Juan Manuel CHM-560 ,BIO-559

Pal Mou RWE-154, THF-146, NSN-70

Pal Umapada SEM-221, BIO-332

Palacios González Cuauhtémoc BIO-391

Palechor Ocampo Anderzon Felipe PPP-500, BIO-454

Palomar Pardave Manuel AMC-335

Palomino Merino Rodolfo MEM-220

Paraguay Delgado Francisco NSN-302

paramo García Ulises BIO-278

Paredes Rueda Miguel Ángel TRB-53

Patiño Marín Nuria BIO-86, CHM-243

Páramo García Ulises BIO-116, SEM-98

Paz López Christian Vianey BIO-236

Pérez Alvarez Jonatan THF-157, BIO-284

Pérez Álvarez Rolando SEM-100

Pérez Arrieta M. L. THF-483, THF-555, AMC-459, CHM-458, AMC-465

Pérez Argelia THF-119

Pérez Barragan D.E. SEM-381

Pérez Bueno José de Jesús RWE-66, BIO-68, SEM-106, SGE-210

Pérez Caro Manuel CHM-415

Pérez Centeno A. SEM-403, SEM-138, THF-405, THF-140, SEM-446

Pérez Coyotl Ana Laura THF-247




505

Pérez Elías THF-7

Pérez Guzmán Manuel Alejandro BIO-213, BIO-212

Pérez Hernández Carlos Guadalupe AMC-214, AMC-228

Pérez Ishiwara David Guillermo NSN-432

Pérez Ladrón de Guevara Héctor THF-306

Pérez Luna José Guillermo CHM-414, PPP-425

Pérez Manuel THF-190

Pérez Ramos Berni Manolo ALD-373, THF-421, ALD-422

Pérez Rodríguez Felipe NSN-207

Pérez Rubén ACS-345, ACS-346

Pérez San Martín Oscar Ivan CHM-307

Pérez Tijerina Eduardo ALD-448

Peña Bautista Alejandro TRB-152

Peña Chapa Juan Luis RWE-567, SCD-568, RWE-244

Peña Gabriel PPP-30

Peña Rodríguez Gabriel TRB-22

Pech Canul M.I. ACS-92

Pech May N. PPP-407

Pedraz Patricia ACS-345

Pedrosa Rodriguez Aura ALD-400

Peralta Álvarez Diana BIO-127

Pernas Salomón René SEM-100

Pescador Rojas José Alfredo NSN-512

Pestaña Oscar ALD-373

Petranovskii Vitalii NSN-209

Pfeiffer Heriberto AMC-473, AMC-511

Piamba Tulcan Oscar Edwin CHM-546

Piña Barba Cristina BIO-539

Pichón Posada Sergio Enrique NSN-225

Piedra Lorenzana A. SEM-553

Piedra Lorenzana Jose Alberto SEM-540

Pimentel Carlos ACS-345

Pina Carlos ACS-345

Pineda Pimentel Maria Guadalupe BIO-235

Polo Parada Luis PPP-201

Ponce Cano Rosa Yetzira NSN-148

Ponce Rosas Ismael AMC-292

Portelles Jorge AMC-305

Portillo Moreno Oscar SEM-397

Pozos Sanchez Gerardo BIO-513

Prasad Somuri THF-344

Prías Barragán Jhon Jairo CHM-334

Prieto Pedro THF-203




506

Prieto Pulido Pedro CHM-334

Puch Ceballos Felipe AMC-459, THF-555, THF-466

Puga A. AMC-459, CHM-458, AMC-465

Pulzara Mora A. THF-311

Pulzara Mora C. THF-311

Quevedo Manuel A. ALD-443

Quevedo López Manuel SEM-164, A. SEM-165

Quiñones-Galván José Guadalupe TRB-470,THF-140, THF-405, NSN-499, SEM-138,

NSN-442, NSN-431, THF-555, NSN-440, SEM-403

Quintanilla Francisco SGE-102

Quintero Pérez Ana Olivia THF-217

Quiroga González Enrique RWE-154

R.P. Ociel ACS-92

Radnev Nikola ALD-275, ALD-271, ALD-274, ALD-270

Rahman Talat S. ACS-289

Rakowiski André Luciano THF-472

Ramírez Baez Mario BIO-135

Ramírez Barrientos Marco Antonio MEM-477

Ramírez Bon Rafael AMC-81, SEM-342, THF-508, SEM-65, SGE-248

Ramírez Dámaso G. RWE-72, RWE-317, RWE-317, RWE-72

Ramírez Enrique AMC-305

Ramírez Esquivel Obed Yamín THF-530

Ramírez Fernández Odín BIO-147

Ramírez Giovanni TRB-125

Ramírez Gutiérrez Cristian Felipe BIO-454, PPP-500, SEM-386

Ramírez Hernández Josué NSN-181

Ramírez Platón I. E. RWE-317, RWE-72

Ramírez Salinas Marco MEM-151

Ramírez Sánchez Omar RWE-424

Ramírez Sotelo María Guadalupe CHM-11, CHM-12

Ramírez Velázquez Lorena Eugenia RWE-204

Ramos Brito Francisco RWE-126, RWE-17, NSN-545, THF-190, THF-328

Ramos Guerra Alma Isabel NSN-76

Ramos Ramón Jesús Alberto SEM-221

Ramos Ramírez Emma Gloria PPP-570

Rangel Ricardo ALD-444

Rangel Segura Ricardo ACS-55, THF-105, SEM-336

Rasia Luiz Antonio THF-472, MEM-266, SCD-457, MEM-449

Raya Rivera Atlántida BIO-129, BIO-131, BIO-136

Rayo Mayoral Patricia CHM-309

Redon Rocio CHM-268

Rejón v. RWE-244

Rejón Moo Víctor RWE-567




507

Renero Francisco J SCD-557

Reséndiz Mendoza Luis Martín RWE-424

Reséndiz Muñoz Juan THF-238

Restrepo Johans PPP-120

Reyes Alcocer E. BIO-514

Reyes Betanzo Claudia MEM-481, THF-247, THF-208, RWE-281, THF-263, BIO-474

Reyes Cervantes Elia Viridiana SEM-242

Reyes Cervantes Eric BIO-103, BIO-513

Reyes Esqueda Jorge Alejandro NSN-512, AMC-484

Reyes Ixta F. P. CHM-458

Reyes Leyva Julio BIO-434

Reyes López Simón Yobanny AMC-525

Reyes Ramírez Bartolome PPP-201

Reyes Usuga Abdul Mauricio ACS-160

Reyes Villagrana Raúl Alberto SEM-61, SEM-62, NSN-304

Reynoso Lara Edmundo CHM-310

Rico Ascencion Omar Itzamna CHM-11, CHM-12

Rincón Arriaga Susana NSN-94

Ríos Camilo BIO-320

Ríos Castañeda Camilo BIO-132

Rivas López Diego Israel CHM-224

Rivas Silva Juan Francisco BIO-332

Rivera Armenta José Luis BIO-116, BIO-283, BIO-278

Rivera Enríquez Claudia Elena SGE-413

Rivera Flores Bertha Luisa SEM-242

Rivera López Jesús Eduardo THF-261

Rivera Márquez José Antonio NSN-388

Rivera Reséndiz Laura P. THF-123

Rivera Rodríguez C. CHM-486

Robles Aguila Maria Josefina SEM-287, SEM-226

Robles C. S. ACS-92

Robles-Águila María Josefina

Rodil Sandra

Rodil Sandra E.

Rodil Posada Sandra Elizabeth BIO-284, TRB-125, THF-157, THF-396

Rodríguez A.G. SEM-519

Rodríguez Betancourtt Verónica María NSN-144

Rodríguez Canto Antonio SGE-102

Rodríguez Carvajal David Alejandro AMC-214

Rodríguez Corvera Cristina de Lourdes RWE-338

Rodríguez Dávila Rodolfo ALD-443

Rodríguez Eugenio THF-396

Rodríguez Fragoso Patricia CHM-310, SEM-333, SEM-232, PPP-233, SEM-550




508

Rodríguez Fuentes Nayeli BIO-539

Rodríguez García Mario Enrique SEM-386, BIO-453, BIO-454, BIO-456, PPP-500

Rodríguez González Julio NSN-114

Rodríguez González Rogelio NSN-324

Rodríguez Juárez Alejandro NSN-95, NSN-97

Rodríguez Llamas Luis Felipe THF-264

Rodríguez López Andrés SEM-153

Rodríguez López Ramón NSN-158

Rodríguez Melgarejo Francisco SEM-96, SEM-172, SEM-387, SEM-111

Rodríguez Meza M. A. ACS-142

Rodríguez Moreno Miguel Angel SEM-245

Rodríguez Rojas Rubén Arturo THF-306

Rodríguez Talavera Rogelio BIO-103, SGE-102, BIO-128, BIO-101

Rodríguez Vargas Isaac SEM-61, NSN-324, SEM-100, SEM-62, NSN-304

Rodríguez Vázquez Ángel Gabriel NSN-518

Rojas Alejandro PPP-30

Rojas Chávez Hugo CHM-363, NSN-366, CHM-301

Rojas Hernández E. RWE-317, RWE-72

Rojas López Marlon NSN-432, BIO-434

Rojas Ochoa Luis Fernando CHM-347

Rojas Rosales J. Antonio NSN-545

Rojo Valerio Alejandro TRB-227

Romano Trujillo Roman NSN-50

Román Doval Ramón BIO-173

Romero De la Cruz María Teresa ACS-222, ACS-346

Romero Gabriel NSN-93

Romero Ibarra Issis Caudette AMC-392

Romero Ibarra Josue Esau RWE-85, NSN-325

Romero Fonseca Ivan THF-44

Roque de la Puente Jorge BIO-316

Rosales Altamirano Omar THF-264

Rosales Andrés CHM-339

Rosales Ernesto PPP-498

Rosales Pedro RWE-281

Rosales Quintero Pedro SEM-191, SEM-192

Rosales Rivera Andrés CHM-516, THF-311 CHM-368

Rosas Becerra Maria Guadalupe AMC-335

Rosendo Andrés Enrique SEM-242, NSN-50, SEM-398

Rubin Daniel NSN-337

Rubio González Carlos BIO-23

Rubio Pereda Pamela ACS-346, ACS-59

Rubio Ponce Alberto ACS-26

Rubio Rosas Efraín BIO-559, BIO-513, NSN-171, BIO-515, SEM-504, BIO-103, NSN-499,




509

SEM-494, BIO-502, NSN-490, SEM-221, NSN-89, AMC-561

Rueda Morales Gabriela Lourdes NSN-163

Ruelas Corral Mario Eduardo ALD-253

Ruiz Bucio Juan-Carlos BIO-554

Ruiz Erika TRB-9

Ruíz Facundo CHM-243, BIO-86

Ruiz Peralta María de Lourdes NSN-185, ACS-186

Ruiz Velazco Graciela BIO-134

Saccone Fabio CHM-339

Sacramento Rivero Julio NSN-94

Salas Juárez Ch. J. SGE-29

Salas Téllez José Antonio CHM-363

Salazar Aparicio Ramses Valente ACS-395, ACS-394

Salazar Cruz Beatriz Adriana BIO-278, BIO-283

Salazar Hernández Raúl THF-46

Salazar Laureles José Luis SEM-13

Salazar Leslie PPP-30

Salazar Montoya Juan Alfredo PPP-570

Salazar Villanueva Martin ACS-186, ACS-130

Salcedo Reyes Juan Carlos ALD-400

Saldaña Saldaña Xóchitl Inés ACS-330

Salgado Ceballos Hermelinda BIO-320 BIO-132

San Juan Hernández Samuel SEM-330

San Martin Martínez Eduardo BIO-231

Sánchez Aké Citlali PPP-255, PPP-188, NSN-382, PPP-375, NSN-117

Sánchez Alarcón Raúl Iván CHM-224 CHM-219

Sánchez Carlos William THF-203

Sánchez Castillo Ariadna NSN-512

Sánchez Dena Oswaldo AMC-517 AMC-484

Sánchez Fernando THF-328

Sánchez González Rodrigo CHM-11

Sánchez Llamazares Jose Luis NSN-399, PPP-188

Sánchez Mora Enrique THF-263, BIO-183

Sánchez Ochoa Francisco ACS-482

Sánchez Oscar AMC-37

Sánchez Pozos Miriam BIO-391

Sánchez Ramírez José Francisco BIO-434, NSN-95, NSN-97, PPP-295, SEM-199, PPP-294

Sánchez Reséndiz Víctor NSN-411

Sánchez Sinencio Feliciano PPP-179

Sánchez Tizapa Marciano NSN-144

Sánchez Torres Stephania BIO-320 BIO-132

Sánchez Valdés Cesar Fidel NSN-399, PPP-188

Sánchez Velarde Emmanuel CHM-11, CHM-12




510

Sánchez Viveros Manuel NSN-209

Sánchez Zeferino Raúl NSN-410

Sandoval Vázquez L. A. THF-483

Santana Rodríguez Guillermo AMC-292, NSN-442, THF-430, RWE-52, NSN-93, RWE-85,

NSN-108

Santana Aranda Miguel Ángel THF-140, SEM-138, SEM-403, THF-405, SEM-446

Santana Rodríguez Guillermo

Santiago Cruz Samuel NSN-114

Santoyo Jaime NSN-93

Santoyo Salazar Jaime NSN-437, NSN-411, NSN-97, NSN-389, BIO-213, RWE-204,

NSN-507 , RWE-85, RWE-52, NSN-431

Sanz F. SEM-98

Sanz Carrasco Fausto SEM-331

Sarmiento-Reyes Arturo MEM-542

Sastré Hernández Jorge SEM-139, SEM-99

Sathish Kumar Kamaraj SEM-168

Saucedo-Sariñana Anilú BIO-180

Sawicki Sandro MEM-449

Scarton Luciane THF-472

Serena Pedro A. ACS-346, ACS-345

Serrano Lázaro José Amauri RWE-438

Shimomura Satoshi NSN-445, SEM-519

Sifuentes Gallardo Claudia NSN-304

Sillas Montaño K. Y. SEM-446

Silva Héctor SEM-65

Silva Galaviz Ernesto SEM-340

Silva González Nicolás Rutilo BIO-183, SEM-242, SEM-221, THF-263

Siqueiros J. TRB-369

Smith Arthur R. ACS-374

Solano Ruiz Esaú THF-211, THF-217

Solís Casados Dora Alicia THF-462, CHM-486

Solís Pomar Francisco ALD-448

Solís Ruíz J. A. BIO-514

Solís Romero José TRB-51, TRB-53

Sosa Fonseca Rebeca CHM-187, SGE-177, CHM-167

Sosa Sánchez José Luis SEM-287, SEM-226

Sotelo de Ávila Artemio Alejandro CHM-12, CHM-11

Sotelo Marquina R.G THF-143

Soto Cruz Blanca Susana SGE-229, SEM-370, SEM-192, SEM-191

Soto Gúzman A. B. AMC-465

Stremsdoerfer Guy RWE-66

Suárez Gómez Amaury NSN-144

Suárez López Jaime Raúl SEM-61, SEM-62, NSN-43




511

Sumaya Martínez Juan NSN-45, THF-46

Sustaita Torres Ireri Aydee NSN-304

Takeuchi Tan Noboru ACS-482, ACS-59, ACS-374

Tamayo-Rivera Lis NSN-512

Téllez-Salazar Wendy AMC-473

Tinoco-Magaña Julio C. BIO-80

Titov Oleg SEM-15

Tiznado Hugo ALD-270, ALD-206, ALD-275, ALD-271, ALD-274, ALD-276

Tolentino Hernández Rafael Valentín SEM-340, SEM-168

Torrealba Meléndez Richard MEM-455

Torres Alfonso RWE-281, SCD-528

Torres Huerta Aidé Minerva THF-396, THF-460

Torres Jacome Alfonso SEM-191

Torres Ochoa Jorge Alejandro CHM-288 CHM-215, ALD-383, ALD-351

Torres Torres Reydezel MEM-477

Torres Walter NSN-124

Tototzintle Huitle H. TRB-470 CHM-458, THF-555

Tovar Sánchez Jean Yves PPP-188

Tranquilino Luis TRB-51

Trápaga Martínez Gerardo THF-508

Trejo Baños Alejandro ACS-365

Trujillo Magdalena THF-303

Turkowski Volodymyr ACS-289

Uribe Héctor ALD-373

Uribe Juárez Omar E. BIO-180

Uribe Omar BIO-136

Uribe Vargas Héctor Manuel ALD-423, NSN-419

Valaguez Velázquez Enrique SEM-480, THF-238, SEM-250, RWE-244, NSN-364

Valderrama Rene ALD-373, THF-429, ALD-435

Valdez S. ACS-92

Valdiero Antonio Carlos MEM-266, THF-472

Valdivia Montes Daniel NSN-388

Valencia Islas A. RWE-317, RWE-72

Valencia Lima J.I. NSN-89

Valenzuela Benavides José NSN-282

Valles Pérez Berenice Y. SEM-387

Valverde Alva Miguel Ángel PPP-188

Varela Caselis Jenaro NSN-185, NSN-171

Vargas Alejandro THF-303

Vargas Galvis Fabio TRB-22

Vargas Islas Sandra Yesenia THF-508

Vargas Muñoz Susana BIO-101, SGE-102, BIO-128, BIO-103




512

Vargas Ortiz Ramón Álvaro SEM-164, SEM-165, BIO-353

Vázquez Chávez Marco Antonio CHM-265

Vázquez Coello J. BIO-514

Vázquez Cortes D. SEM-519

Vásquez García Salomón Ramiro BIO-236, BIO-235

Vázquez Hernández Fabiola SEM-377

Vázquez Leal Hector MEM-542

Vázquez Nava Raul Alfonso ACS-395, ACS-394

Vázquez Valerdi Diana Elizabeth THF-48

Vázquez Zubiate Lizeth NSN-532

Vélez Tenorio Fernando Roberto THF-211

Velarde Escobar Oscar Jesús THF-190, THF-328, NSN-545, RWE-126, RWE-17

Velasco Santos Carlos BIO-23

Velázquez Cruz Evaristo Isac THF-84

Velásquez Dalazar A.A. CHM-368

Velázquez López Eréndira sem-99

Velázquez Mancilla Rodolfo TRB-53

Velásquez Ordoñez C. CHM-187

Velázquez Pérez Enrique SEM-15

Velásquez Salazar Abilo Andrés CHM-516

Velosillo Perceval ACS-346

Vera Robles L. Irais SGE-277

Vidal Borbolla Miguel Ángel ALD-412, NSN-409, SEM-408 ALD-497

Vigueras Santiago Enrique AMC-484, NSN-279

Vilhena J. Guilherme ACS-345, ACS-346

Villagrán Arrollo Edgar Iram CHM-265

Villagrán Muniz Mayo PPP-375, PPP-188, NSN-382

Villalobos Correa Daniel Eduardo THF-44

Villaneda Saldívar B. AMC-465

Villanueva Cab Julio RWE-154

Villanueva Ibañez Mario SEM-196

Villarreal Lucio Diana Samantha BIO-116

Villegas Mercado A. M. THF-466

Vivaldo Israel RWE-281

Vivas Castro Juan Jesus NSN-163

Volovichev Igor RWE-20

Vorobiev Yurii SEM-342

Wagner Mota da Silva Geferson Gustavo THF-472

Woo Garcia Rosa María MEM-220

Yacamán Miguel José ALD-448

Yáñez Andrea BIO-453

Yáñez Limón José Martín AMC-81

Yee Rendón Cristo Manuel NSN-545, RWE-17, RWE-126, CHM-415, THF-190, THF-328




513

Yescas Mendoza Edgardo THF-84

Yu. Gorbatchev Andrei SEM-67

Zaca Moran Orlando BIO-434, THF-247

Zaca Moran Placido THF-247

ZACAHUA-TLACUATL GREGORIO NSN-209

Zalazar-Ramírez Bertha S. CHM-258, CHM-251

Zambrano Gustavo AMC-37

Zambrano Arjona M. PPP-467

Zamilpa Alejandro NSN-432

Zamora Peredo Luis NSN-193, THF-254, NSN-205, SEM-49

Zamudio Torres Ildefonso SEM-106

Zapata Torres Martín SEM-480, THF-238, RWE-244. SEM-138, NSN-364, THF-140.,

SEM-250

Zavala Alonso Norma Verónica CHM-243, BIO-86

Zavala Moran Ulises NSN-69, SEM-67

Zayas Bazán Patricia G. RWE-85

Zayas Saucedo María Elena AMC-88, AMC-228, AMC-214

Zúñiga Carlos SEM-313

Zelaya Ángel Orlando NSN-499, RWE-204. THF-286, SEM-65, THF-261, CHM-310,

THF-298, SEM-381

Zepeda Pedreguera Alejandro NSN-94

Zúñiga Islas Carlos MEM-22

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