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Dr. Ptak is a Senior Scientist in the National Center for Photovoltaics. He received his doctorate from West Virginia University where he worked on growth kinetics and doping of III-Nitride materials grown by molecular beam epitaxy (MBE). He joined NREL after graduation in 2001 and has since worked on the growth and characterization of various materials and devices, including dilute nitrides and dilute bismides, coincident-site lattice matched alloys, and other novel materials for photovoltaic applications. Recent work has focused on the use of hydride vapor phase epitaxy to enable the use of highly efficient III-V materials in one-sun and low-concentration applications. Dr. Ptak has authored or co-authored more than 90 papers and 2 book chapters, given more than 50 invited and contributed presentations, and been awarded two patents. His research interests include growth kinetics, MBE of new materials, low-cost III-V deposition techniques, and photovoltaic materials and devices.

Featured Publications

The Relation of Active Nitrogen Species to High-Temperature Limitations for (0001) GaN Growth by Radio Frequency Plasma-Assisted Molecular Beam Epitaxy, A.J. Ptak, M.R. Millecchia, T.H. Myers, K.S. Ziemer, and C.D. Stinespring, Appl. Phys. Lett. 74, 3836 (1999).

Faceted inversion domain boundary in GaN films doped with Mg, L.T. Romano, J.E. Northrup, A.J. Ptak and T.H. Myers, Appl. Phys. Lett. 77, 2479 (2000).

Magnesium Incorporation in GaN Grown by rf-Plasma Assisted Molecular Beam Epitaxy, A.J. Ptak, T.H. Myers, L.T. Romano, C.G. Van de Walle and J.E. Northrup, Appl. Phys. Lett. 78, 285 (2001).

Controlled Oxygen Doping of GaN using Plasma Assisted Molecular-Beam Epitaxy, A.J. Ptak, L.J. Holbert, L. Ting, C.H. Swartz, M. Moldovan, N.C. Giles, T.H. Myers, P. Van Lierde, C. Tian, R.A. Hockett, S. Mitha, A.E. Wickenden, D.D. Koleske and R.L. Henry, Appl. Phys. Lett. 79, 2740 (2001).

View all NREL publications for Aaron Ptak.