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© 2015 Boise State University 1 Looking into the nanoworld with the help of lasers (Laser spectroscopy of novel nanomaterials) Department of physics Dmitri A. Tenne

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Page 1: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 1

Looking into the nanoworld with the help of lasers

(Laser spectroscopy of novel nanomaterials)

Department of physicsDmitri A. Tenne

Page 2: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 2

What are nanomaterials ? Artificially engineered structures at nanometer

(one billionth of a meter) scale in one, two, or all three dimensions

2D nanostructures: ultrathin films and multilayered structures

1D nanostructures: nanowires, nanotubes

0D nanostructures: nanocrystals (aka quantum dots)

M. Varela et al. in Scanning Transmission Electron Microscopy, ed. by S.J. Pennycook and P.D. Nellist (Springer, 2011)

Luo et al. Appl. Phys. Lett. 83, 440 (2003)

S. Adireddy et al. Chem. Mater. 22, 1946 (2010)

Page 3: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 3

Complex oxides: functional properties and applications

Image from A. Rothschild, http://matwww.technion.ac.il/Rothschild/Research.html#

high-temperature superconductivity (YBa2Cu3O7) ferroelectricity and piezoelectricity (PbZrxTi1-xO3,

BaxSr1-xTiO3); giant permittivity (CaCu3Ti4O12); colossal magnetoresistance (La1-xSrxMnO3); ionic (YxZr1-xO2), electronic (AlxZn1-xO2),

and mixed ionic-electronic conductivity (SrTi1-xFexO3);

semiconductors (ZnO) photocatalytic activity (TiO2); gas sensitivity (SnO2);

• • •⇒ many electronic, optical and

electrochemical devices including:• nonvolatile memories • sensors and actuators • transparent electrodes

• solar cells • chemical sensors • fuel cells and batteries

• electro-optic modulators • electrochromic windows • catalysts and photocatalysts

Page 4: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 4

Physical science of nanomaterials: many participants involved

• Theoretical modeling (our collaborators)

• Samples synthesis (more collaborators)

• Structural characterization (collaborators and BSU facilities)

• Studies of physical properties (that’s where we belong!)

• … device design and fabrication

Page 5: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 5

Boise State University: Departments of Physics, Electrical and Computer Engineering, Materials

Science and Engineering

Cornell University

Oak Ridge National Laboratory

COLLABORATORS

University of Wisconsin -

Madison

Temple University

Penn State University

Argonne National Laboratory

Page 6: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 6

Our part: probing the physical behavior by laser spectroscopy methods

emitted andscattered

light

incidentlight

z

x

y

reflectedlight

• a material is illuminated by light which characteristics are known;

• light can be: - reflected (reflectivity, ellipsometry)

- absorbed by a material(absorption spectroscopy)

- re-emitted from material (photoluminescence)

- scattered by a material (light scattering)

Raman spectroscopy

Page 7: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 7

Photoluminescence

350 400 450 500 550

102

103

104

105

3.5 3.4 3.3 3.2 3.1 3 2.9 2.8 2.7 2.6 2.5 2.4 2.3

Inte

nsity

(arb

.uni

ts)

Wavelength (nm)

T=10 Kλi = 325 nm

Energy (eV)

• Pure ZnO emits in the near UV range• Defects such as vacancies, interstitials, or impurities lead to the

light emission in the visible range – great for biological applications (can see them in optical microscope)

Example: zinc oxide, ZnO

Page 8: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 8

Raman spectroscopy

Chandrasekhara Venkata Raman

The Nobel Prize in Physics 1930

• a material or a molecule scatters irradiant light from a source • Most of the scattered light is at the same wavelength as the laser

source (elastic, or Raileigh scattering) • but a small amount of light is scattered at different wavelengths

(inelastic, or Raman scattering)

Stokes Raman

Scatteringωi- Ω(q)

Anti-Stokes Raman Scatteringωi+ Ω(q)

ωi

Elastic (Raileigh) Scattering

ω

I

0

αβ

ћΩ

ћωiћωsStokes

0

αβ

ћΩ

ћωi

Raileigh

ћωsAnti-Stokes

Analysis of scattered light energy, polarization, relative intensity provides information on properties of material under study (e.g. vibrations of atoms in a crystal or molecule)

Page 9: Dmitri A. Tenne...Dmitri A. Tenne Department of Physics, Boise State University Office: MP 312A, Lab: MP 302 Tel: 208-426-1633 Email: dmitritenne@boisestate.edu Title Boise State PowerPoint

© 2015 Boise State University 9

Contact: Dmitri A. TenneDepartment of Physics, Boise State University Office: MP 312A, Lab: MP 302

Tel: 208-426-1633 Email: [email protected]