Vijay D'Costa

ERC 163, Arizona State University, Tempe, AZ

Email: vdcosta@mainex1.asu.edu

 
 

EDUCATION

PhD in Physics, 12/2006
Department of Physics, Arizona State University, Arizona

M.S in Physics, 12/2004
Department of Physics, Arizona State University, Arizona

PROFESSIONAL EXPERIENCE

Assistant Research Scientist April 2007 - Present
School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona

  • Type-II superlattice structures (InAs/InAsSb, InAs/GaSb) for LWIR photodetector applications (Infrared optical constants, Band gaps, and absorption coefficient)
  • Optical properties of ZnTe films grown on various III-V substrates
  • Optical Characterization of Ga-doped poly-crystalline ZnO films (Doping, resitivity, mobility, vibrational modes, optical constants, and absorption coefficient)

Assistant Research Scientist/Postdoctoral Research Associate 01/07-03/10
Department of Physics, Arizona State University, Tempe, Arizona

  • Developed models and applications of spectroscopic ellipsometry for characterization of thin films
  • Determined optical constants and absorption coefficient of various novel materials for exploring their potential in detector, sensor and photovoltaic applications.
  • Measured the compositional dependence of energy gaps (infrared to ultraviolet energy range) in the electronic band structure of various materials for band gap engineering
  • Transport properties (doping including depth profile, resistivity, mobility) of various doped materials and device heterostructures using infrared spectroscopic ellipsometry
  • Studied the dielectric response of SiO2, HfO2, Si3N4, and Si3PN4
  • Investigated the presence of selective growth of pure Ge or SiGe alloys in source/drain regions of prototype device structures using Raman spectroscopy
  • Measured the optical constants and reflectivity of metallic compounds (ZrB2, HfB2 and ZrHfB2) alloys by spectroscopic ellipsometry
  • Dielectric function of a-Si and nano-crystalline Si. Developed an ellipsometry scheme to distinguish between amorphous and crystalline materials
  • Studied strained GeSn, SiGe, Si and Ge by spectroscopic ellipsometry, Raman spectroscopy, and photoreflectance

Graduate Research Associate 2006
Dissertation: Electronic and Vibrational Properties of Germanium-Tin and Silicon-Germanium-Tin Alloys.

  • Studied the compositional dependence of phonon modes and electronic transitions in GeSn and SiGeSn alloys. Discovered that the energy gaps and the phonon modes show interesting scaling behavior

Graduate Research Assistant 2004 - 2005

  • Developed an ellipsometry fitting program to measure the compositional dependence of energy gaps for understanding the basic physics and band gap engineering
  • Carried out photoluminescence and Raman studies for exploring the potential of novel III-V and Group-IV materials in optoelectronics
  • Characterized a-plane GaN films grown on sapphire by cathodoluminescence

Graduate Teaching Assistant 2002 - 2003

SELECTED PUBLICATIONS IN REFEREED JOURNALS

1. V.R. D'Costa, Y.-Y. Fang, J. Tolle, J. Kouvetakis and J. Menéndez, Ternary SiGeSn alloys: New opportunities for strain and bandgap engineering using group IV semiconductors, Thin Solid Films 518, 2531 (2010)

2. V. R. D'Costa, Y.-Y. Fang, J. Tolle, J. Mathews, R. Roucka, J. Kouvetakis, and J. Menéndez, Sn-alloying as a means of increasing the optical absorption of Ge at the C- and L telecommunications bands, Semicond. Sci. Technol. 24 115006 (2009)

3. V. R. D'Costa, J. Xie, J. Tolle, J. Kouvetakis, and J. Menéndez, Infrared dielectric function of p-doped Ge0.98Sn0.02 alloys, Phy. Rev. B 80, 125209 (2009).

4. V. R. D'Costa, Y.-Y. Fang, J. Tolle, A.V.G. Chizmeshya, J. Kouvetakis, and J. Menéndez, Tunable electronic structures at fixed lattice constant in group-IV semiconductor alloys, Phy. Rev. Lett. 102, 107403 (2009).

5. J. Tolle, V. D'Costa, Junqi Xie, A.V.G. Chizmeshya, J. Menendez and J. Kouvetakis, An in situ molecular approach to nanoscale p- and n-doping of Ge1-xSnx semiconductors: structural, electrical and transport properties, Solid State Electronics 53(8), 816-823 (2009).

6. Y-Y Fang, V. R. D' Costa, J. Tolle, J. Menendez and J. Kouvetakis, Strained metastable structures and selective area epitaxy of Ge-rich Ge1-xSix /Si(100) materials using nanoscale building blocks, Solid State Communications 149, 78-81 (2009).

7. Y.-Y. Fang, V. R. D'Costa, J. Tolle, C. D. Poweleit, John Kouvetakis, and José Menéndez, Strained Si films grown by chemical vapor deposition of trisilane on Ge buffered Si (100), Thin Solid Films 516, 8327-8332 (2008).

8. R. Roucka, V.R. D'Costa, Y.-J. An, M. Canonico, J. Kouvetakis, J. Menendez and A.V.G Chizmeshya, Thermoelastic and optical properties of thick boride templates on silicon for nitride integration applications, Chem. Mater. 20, 1431-1442, 2008.

9. V. R. D'Costa, J. Tolle, R. Roucka, C. D. Poweleit, J. Kouvetakis, J. Menéndez, Raman scattering in Ge1-ySny alloys, Solid State Communications, 144, 240-244 (2007).

10. V. R. D'Costa, J. Tolle, C. D. Poweleit, J. Kouvetakis, J. Menéndez, Compositional dependence of Raman mode frequencies in ternary Ge1-x-ySixSny alloys, Phys. Rev. B 76, 035211 (2007).

11. Vijay R. D'Costa, José Menéndez, Candi S. Cook, John Tolle, John Kouvetakis, Stefan Zollner, Transferability of Optical Bowing Parameters between binary and ternary Group-IV alloys, Solid State Communications, 138, 309-313 (2006).

12. Vijay R. D'Costa, Candi S. Cook, A. G. Birdwell, Chris L. Littler, Michael Canonico, Stefan Zollner, John Kouvetakis, José Menéndez. Optical properties of thin-film Ge1-ySny alloys: A comparative Ge1-ySny/Ge1-xSix study, Phys. Rev. B 73, 125207 (2006).

SELECTED CONFERENCE TALKS /PROCEEDINGS

1. V. R. D'Costa, E. H. Steenbergen, Y. Huang, J.-H. Ryou, R. D. Dupuis, Y.-H. Zhang, Infrared Dielectric Function of InAs/InAsSb Type-II Superlattices, 5th International Conference on Spectroscopic Ellipsometry, May 23rd - 28th, 2010, Albany, NY.

2. V. R. D'Costa, Group-IV semiconductors incorporating Sn, 9th July 2009, seminar presentation at Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln.

3. Vijay R. D'Costa, John Tolle, Junqi Xie, José Menéndez, and John Kouvetakis, Transport properties of GeSn alloys, 29th International Conference on the Physics of Semiconductors, July 27- August 01, 2008, Rio de Janeiro, Brazil.

4. Vijay R. D'Costa, José Menéndez, John Tolle, Yanyan Fang, and John Kouvetakis, Direct absorption edge in GeSiSn alloys, presented at 29th International Conference on the Physics of Semiconductors, July 27- August 01, 2008, Rio de Janeiro, Brazil.

5. Vijay R. D'Costa, José Menéndez, Andrew V.G. Chizmeshya, John Tolle and John Kouvetakis: Structural, Vibrational, and Electronic Properties of Ternary SixGe1-x-ySny Alloys: presented at 2006 APS March Meeting, Baltimore, MD.

6. Vijay D'Costa, Andrew Chizmeshya, Candi Cook, John Kouvetakis and José Menéndez: Bowing in the Compositional Dependence of Optical Transitions in Ge1-ySny alloys: presented at 2005 APS March Meeting, Los Angeles, CA.

BOOKS

Electronic and Vibrational Properties of GeSn and SiGeSn alloys, Vijay D'Costa, VDM Verlag Dr. Müller (2009).

HOBBIES

Ballroom dancing, fitness and sports.