chemical vapour deposition and

8/4/2019 Chemical Vapour Deposition And

1/51

GRAPHENE

SYNTHESIS USING

CATALYTIC

CHEMICAL VAPOUR

DEPOSITION

PRESENTED BY,

ARUNI S.

MS, CNN

M.G.UNIVERSITY


2/51

CONTENTS CHEMICAL VAPOUR DEPOSITION

1. Introduction

2. General outline and Mechanism

3. Applications of CVD4. Advantages and disadvantages

5. Classification

GRAPHENE

CATALYTIC CHEMICAL VAPOUR DEPOSITION OF GRAPHENE


3/51

CHARACHTERISATION

APPLICATION

CONCLUSION

FUTURE

REFERENCES


4/51

CHEMICAL VAPOUR DEPOSITION


5/51

Chemical Vapour Deposition (CVD)

- is a chemical process used to produce high - purity,

high performance solid materials

- its often used in semiconductor industry to producethin films and coatings

- it is a technique for synthesizing materials in whichchemical components in vapour phase reacts to form a

solid on a surface

- the primary requirement is that the materials muststart out in the vapour phase


6/51

GENERAL OUTLINE


7/51

Schematic Representation of a Chemical Vapour Depositor


8/51

GENERAL CVD PROCESS

Deposition of thin film includes the transport of one or more volatileDeposition of thin film includes the transport of one or more volatileprecursors in vapour phase to the reaction chamber, where it decompose on aprecursors in vapour phase to the reaction chamber, where it decompose on a

heated surface.heated surface.


9/51

Steps involved in deposition

- Transport of the materials in gas phase to deposition zone

- Diffusion or convection of gaseous precursors through theboundary layer

- Adsorption of film precursors on to the growth surface

- Surface diffusion precursors to growth sites

- Surface chemical reactions leading to the deposition of a film

- Desorption of by products

- Transport of gaseous by products out of the reactor


10/51

MECHANISM OF DEPOSITION

Two main steps :

- transport of gas phase materials to the

reaction zone and reaction of materials

- deposition of film on the substrate


11/51

Transport process involves gas supply, convection and diffusion ofgaseous reactants

Deposition process involves adsorption of reactant species on to the

substrate surface, surface chemical reaction between the reactants,diffusion of the by products and film deposition

Forced and Free convection

Viscous friction

Diffusion


12/51

SCHEMATICAL REPRESENTATION OF THE MECHANISMOF GROWTH


13/51

Important factors that influence the homogeneous reaction:

- gas residence time near the surface and gas heating

Gas phase reactions are homogeneous and produce powderymaterial

Surface reactions are heterogeneous and produce thin films

In the end desorption and diffusion of by - products


14/51

APPLICATIONS OF CVD

Deposition of materials in micro and nano fabrication into

various forms including monocrystalline, polycrystalline,

amorphous.

Silicon, Carbon fibre, Carbon nano fibres (CNF)/nano

filaments/ nano rods, Silicon di oxide, Silicon

Germanium, Tungsten, Silicon carbide nanostructure, Silicon

nitride nanomaterials, Silicon oxynitride, Titanium nitride andvarious high kdielectrics can be deposited


15/51

Synthetic diamonds and nanodiamonds

Largely hard coatings to improve the life andperformance of cutting tools

In microelectronics industry


16/51

In glass industry to coat large glass panels with SnO2,TiN or SiO2

Layers in solar cells, coatings for catalysts,membranes or optical layers in waveguides

Synthetic gold coatings are deposited on largevolumes of personal jewelry


17/51

ADVANTAGES & DISADVANTAGES

ADVANTAGES :

Can deposit materials which are hard to evaporate

Increased flexibility and Good reproducibility

Low maintenance

High yields

High efficiency

Can grow epitaxial films


18/51

DISADVANTAGES

High temperatures

Complex processes

Toxic and corrosive gasses


19/51

CLASSICATION OF CVD

Based on

- means by which chemical reactions areinitiated

- process conditions


20/51

I. According to the operating pressure

Atmospheric Pressure CVD (APCVD)

- occurs at atmospheric pressure

Low Pressure CVD (LPCVD)

- occurs at sub atmospheric pressure

Ultrahigh Vacuum CVD (UHVCVD)

- the process takes place typically below 10-6 Pa


21/51

II. According to the physical characteristics ofvapour used

Aerosol Assisted CVD (AACVD) :

- precursors are transported to substrate through liquid/gasaerosol

- suitable for involatile precursors


22/51

Direct Liquid Injection CVD (DLICVD)

- precursors are in liquid form

- suitable for solid and liquid precursors

- high growth rates can be achieved


23/51

Metalorganic CVD (MOCVD)

- based on metalorganic precursors

- deposition of a wide variety of materials

- easy removal of by products

- high purity


24/51

III. According to the source of energy supplied

Plasma enhanced CVD (PECVD)

- plasma is created to enhance the chemicalreaction rates of the precursors, by RF frequencyor DC discharge

- deposition at lower temperatures


25/51

- wide variety of nano materials can be deposited

- high quality and good alignment

Rapid Thermal CVD (RTCVD)

- heating only at substrate by heating lamps or othermeans

- reduce unwanted gas phase reaction


26/51

Catalytic CVD (CCVD/Cat - CVD)

- also known as Hot filament CVD (HFCVD) or Hot

wire CVD (HWCVD)

- hot filament is used to supply the required energy

- nano diamond, CNT and graphene and a widevariety of nanomaterials can be produced


27/51

GRAPHENE

A flat monolayer carbon atoms highly

packed into 2 D honey comb lattice and is

a building block for graphite materials of allother dimensionalities

Term coined by Hanns Peter Boehm


28/51

Allotrope of Carbon with one atom thick

planar sheets of sp2 bonded carbon atoms C C bond length is 0.142 nm

Nobel Prize in Physics for2010 for Andre

Geim and Konstantin Novosolov


29/51

They extracted the material from a piece of graphite such as

that found in ordinary pencils using adhesive tape, repeatingthe tape - trick until they were left with miniscule flakes ofgraphene.


30/51

Honey comb structure of graphene


31/51

Can be wrapped up to

0D fullerenes

1D nanotubes

3D graphite


32/51

PROPERTIES

Atomic properties

Electronic properties Mechanical properties

Thermal properties

Biological properties


33/51

CATALYTIC CHEMICAL VAPOURDEPOSITION OF FEW LAYERED

GRAPHENE

MgO Co catalyst is used

Catalyst prepared by dissolving 5 g MgO in0.36 g Cobalt nitrate hexahydrate in 100mlethanol

Ultra sonication for 1hr and drying for1300C for 12hr and ground to fine powder


34/51

Catalyst loaded in ceramic boat in CCVD isreacted with methane at a rate of 375ml/min at10000C for 30 min.

Purification:

- Product is acidized by con. HCl toremove MgO and Co particles

- Washing with demineralised water toattain neutral pH and dried at 700C


35/51

RESULT

After purification 50g

graphene was

obtained from 500g of

loaded catalyst.

Therefore the yield of

reaction is 10%.


36/51

CHARACHTERISATION

Scanning Electron Microscopy (SEM)

High Resolution Transfer Electron Microscopy

(HRTEM) Atomic Force Microscopy (AFM)

XPS

Raman Spectroscopy X-ray Diffraction Spectroscopy (XRD)


37/51

SEM

Fig. a Fig. b

a) Field-emission SEM image of few-layered graphene grown by CVD.

b) High-magnification SEM image of few-layered graphene.


38/51

HRTEM

Fig. a Fig. b Fig. c

a) HRTEM image of few-layered graphene, showing individual graphene sheets with the edgesof the graphitized layers.

b) HRTEM image of sutured and crumpled graphene paper; solid triangles indicate ripples inthe few-layered graphene.

c) HRTEM image of as-grown graphene without purified treatment process.


39/51

AFM, XPS & RAMAN SPECTRUM

AFM image of the few layered graphene

materials

a. Wide survey of XPS spectrum of sample

b. Typical Raman spectrum for few layered

graphene


40/51

XRD


41/51

APPLICATIONS

Semi conductor interconnects & IC chips

Chemical and gas sensors

Quantum computers Paper battery and Battery electrodes

EMI & RFI shielding applications

Electrostatic paints especially for automobileparts

Conducting ink


42/51

Printed Electronics Fuel cells and ultra capacitors

Aerospace Thin film industry Composite application Defense application

Solar panels and cells Bio devices mainly for DNA sequencing


43/51

DEVELOPED PRODUCTS

Transparent graphene

electrode

Ultra strong paper from

graphene

Proof of principle

transistors, loop device andcircuitry


44/51

Graphene microchipFlexible touch screen

made of graphene Transparent conductive films on PI

and glass substrates


45/51

Graphene ink

Solar panel coating

Graphene armour


46/51

CONCLUSION

The successful synthesis of few layered graphene

through catalytic chemical vapour deposition can

bescaled upto large scale. This approach not onlyopens a new, low cost, method to produce graphene

industrially, but it also provides a realistic possibility

of graphene applications in molecular electronics and

polymer composites.


47/51

PROMISING FUTURE


48/51

REFERENCES

Chemical Vapour Deposition by Xianbao Wang,

Haijun You, Fangming Liu, Mingjian Li, Li Wan, Qin

Li, Yang Xu, Rong Tian, Ziyong Yu, Dong Xiang andJing Cheng

Substrate free synthesis of large area, continuous

multi - layer graphene film by Fang Liu, Yong Zhang


49/51

Graphene Synthesis by CVD on Copper Substrate by Mark

Borysiak.

Formation of Bilayer Bernal Graphene: Layer by Layer

Epitaxy via Chemical Vapour Deposition by Kai Yan, HailinPeng, Yu Zhou, Hui Li and Zhongfan Liu

Large Area, Few Layer Graphene Films on Arbitrary

Substrates by Chemical Vapour Deposition by Alfonso Reina,

Xiaoting Jia, John Ho, Daniel Nezich, Hyungbin Son, VladimirBulovic, Mildred S., Dresselhaus and Jing Jong


50/51

Direct Chemical Vapour Deposition of Graphene on Dielectric

Surfaces by Ariel Ismach, Clara Druzgalski, Samuel Penwell,

Adam Schwartzberg, Maxwell Zheng, Ali Javey, Jeffrey Bokor

and Yuegang Zhang Introduction to Nanoscience and Nanotechnology by

Chattopadhyay

Chemical Vapour Deposition Mechanism by Conggin Miao,

Churan Zheng, Owen Liang and Ya Hong Xie.


51/51

THANK YOU

chemical vapour deposition and

Documents