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Angelo Mascarenhas — Research Fellow

Dr. Angelo Mascarenhas has done extensive research on harnessing the material consequences of semiconductor alloy instabilities, including spontaneous ordering and spontaneous composition modulation for optoelectronic applications.

His work focuses on spectroscopic research on semiconductor materials for photonics and advanced solar cells.

Dr. Angelo Mascarenhas is a manager of the Experimental Materials Sciences Group and project leader for Experimental Condensed Matter Physics in the Energy Sciences directorate at NREL. He received his Ph.D. in physics from the University of Pittsburgh in 1986 under the guidance of Prof. W.J. Choyke (formerly at Westinghouse Labs) and did postdoctoral research with Dr. Jaques Pankove, when NREL was still known as the Solar Energy Research Institute (SERI). Since then he has been working at NREL in the area of spectroscopic research on semiconductor materials for photonics and advanced Solar Cells.

Research and Contributions

Dr. Mascarenhas was the project leader for Solid State Spectroscopy for the past 22 years and has done extensive research on harnessing the material consequences of semiconductor alloy instabilities, such as spontaneous ordering and spontaneous composition modulation for optoelectronic applications. His research related to the consequences of spontaneous lateral composition modulation on the optical properties of short period superlattices helped pioneer this very novel field. More recently, he introduced the study of dilute bismide alloys as an analogous counterpart of dilute nitride alloys, which has significant implications for photovoltaics as well as the field of spintronics. Dr. Mascarenhas also invented the concept of isoelectronic co-doping for tailoring the optical properties of semiconductor alloys for applications related to very high efficiency solar cells, solid state lighting, and advanced communication lasers. He is an author of 260 scientific publications and is a fellow of RASEI, a joint NREL-CU renewable energy institute.

Education

  • Ph.D. Physics, University of Pittsburgh (1986)
  • B. Technology, Electronics and Electrical Communications Engineering, IIT Kharagpur (1980)

Professional Activities

  • RASEI Fellow, NREL/University of Colorado Boulder, 2010-2013
  • Member of Energy Materials Technical Working Group on Multi-Materials Integration in Energy Systems, 2010
  • Program Chair for 33rd International Symposium on Compound Semiconductors, Vancouver, Canada, 2006
  • NSF EPSCOR Program, Oklahoma State, Advisory Board, 2002-2005
  • Member of NIH Center for Scientific Review Committee, 2004
  • Symposia Organizer: MRS Fall-95 Meeting, MRS Fall-99 Meeting, APS March-99 Centennial Meeting, Int. Conf. on materials for Advanced Technologies, 2003.

NREL Awards

  • Chairmans Award (2012): For Exceptional Performance.
  • Directors Award (2003): For Outstanding Performance.
  • NREL Staff Award (1996): For Outstanding Achievement.
  • MRI Presidents Award (1991): For Exceptional Performance.

Patents and Publications

Patents: Independent and by Collaboration

  1. Lattice-mismatched GalnP LED devices and methods of fabricating the same
  2. SuperStrate Sub-Cell Voltage-Matched Multijunction solar cells
  3. Photovoltaic Device
  4. Boron, Bismuth Co-Doping of Gallium Arsenide and other compounds for Photonic and Heterojunction Bipolar Transistor Devices
  5. High Bandgap III-V Alloys for High Efficiency Optoelectronics
  6. Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps
  7. Lattice-mismatched GalnP LED Devices and Methods of Fabricating Same
  8. Disorder-Order Homojunctions as Minority-Carrier Barriers
  9. Optoelectronic devices having a direct band-gap base and an indirect band-gap emitter
  10. Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps
  11. Monolithic photovoltaic energy conversion device
  12. Voltage-matched, monolithic, multi-band-gap devices
  13. Multi-junction, monolithic solar cell with active silicon subrate
  14. Isoelectronic co-doping
  15. Voltage-matched, monolithic, multi-band-gap devices
  16. Isoelectronic co-doping

Selected Publications

  1. Fluegel, B., Mialitsin, A.V., Beaton, D.A., Reno, J.L., and Mascarenhas, A. Electronic Raman scattering as an ultra-sensitive probe of strain effects in semiconductors. Nature Communications 6 (2015): 7136.
  2. Alberi, K. Crooker, S.A., Fluegel, B., Beaton, D.A., Ptak, A.J. and Mascarenhas, A. Magnetic field-induced delocalized to localized transformation in GaAs:N. Phys. Rev. Lett. 110 (2013): 156405.
  3. Alberi, K., Fluegel, B., Dhere, R., Crooker, S.A., and Mascarenhas, A. Measuring Long-Range Carrier Diffusion Across Multiple Grains in Polycrystalline Photovoltaics. Nature Comm. 4 (2013): 2699.
  4. Mialitsin, A., Fluegel, B., Ptak, A. and Mascarenhas, A. Mechanism of asymmetric lineshape broadening in GaAs1-xNx Raman spectra. Phys. Rev. B 86 (2012): 045209.
  5. Fluegel, B., Mascarenhas, A., Snoke, D., Pfeiffer, L.N., and West, K. Plasmonic al-optical tunable wavelength shifter. Nature Photonics 1, no. 12 (2007): 701.
  6. Zhang, Y. et al. (2007). Zero Thermal Expansion in Hybrid Organic-Inorganic semiconductors. Phys. Rev. Lett. 99 (2007): 215901.
  7. Zhang, Y., Wang, LW, and Mascarenhas, A. Quantum coaxial cables for solar energy harvesting. Nanoletters 7, no. 5 (2007): 1264.
  8. Zhang, Y., Mascarenhas, A., et al. Novel Approach of Tuning the Physical Properties of Organic-Inorganic Hybrid Semiconductors. Phys. Rev. Lett. 96 (2006): 026405.
  9. Karaiskaj, D., Engtrakul, C., McDonald, T., Heben, M.J., and Mascarenhas, A. Intrinsic and Extrinsic Effects in the Temperature-Dependent Photoluminescence of Semiconduction Carbon Nanotubes. Phys. Rev. Lett. 96 (2006): 106805.
  10. Fluegel, B., Francoeur, S., and Mascarenhas, A. Giant Spin-Orbit Bowing in GaAs1-xBix. Phys. Rev. Lett. 97 (2006): 067205.
  11. Fluegel, B., Zhang, Y., Mascarenhas, A., Huang, X., and Li, J. Electronic properties of hybrid organic-inorganic semiconductors. Phys. Rev. B. 70 (2004): 205308.
  12. Francoeur, S., Klem, J.F., and Mascarenhas, A. Optical spectroscopy of single impurity centers in semiconductors. Phys. Rev. Lett. 93 (2004): 67403.
  13. Zhang, Y., Fluegel, B., and Mascarenhas, A. Total Negative Refraction Refraction in Real Crystals for Ballistic Electrons and Light. Phys. Rev. Lett. 91 (2003): 157404.
  14. Li, J.H., Moss, S.C., Zhang, Y., Mascarenhas, A. Pfeiffer, L.N., West, K.W., Ge, W.K., and Bai, J. Layer Ordering and Faulting in (GaAs)n/(AlAs)n Ultrashort-Period Superlattices. Phys. Rev. Lett. 91 (2003): 106103.
  15. Perkins, J.D., Mascarenhas, A., Zhang, Y., Geisz, J.F., Friedman, D.J., Olson, J.M., and Kurtz, S.R. (1999). N-activated transitions, level repulsion and band gap reduction in Ga1-xAsxN (x<0.03). Phys. Rev. Lett. 82 (1999): 3312–3315.

NREL Publications

View NREL Publications for Angelo Mascarenhas.