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Electrical and Computer Engineering

Electrical and Computer Engineering Publications

2003

MOLECULAR-BEAM EPITAXY

Articles 1 - 3 of 3

Full-Text Articles in Engineering

Generation–Recombination Noise In Gallium Nitride-Based Quantum Well Structures, Rolando S. Duran, Grover L. Larkins Jr., Carolyn M. Van Vliet, Hadis Morkoç Jan 2003

Generation–Recombination Noise In Gallium Nitride-Based Quantum Well Structures, Rolando S. Duran, Grover L. Larkins Jr., Carolyn M. Van Vliet, Hadis Morkoç

Electrical and Computer Engineering Publications

Electronic noise has been investigated in AlxGa1−xN/GaN modulation-doped field-effect transistors of submicron dimensions, grown by molecular beam epitaxy techniques. Some 20 devices were grown on a sapphire substrate. Conduction takes place in the quasi-two-dimensional (2D) layer of the junction (xy plane) which is perpendicular to the triangular quantum well (z direction). A nondoped intrinsic buffer layer separates the Si-doped donors in the AlxGa1−xN layer from the 2D transistor plane. Since all contacts must reach through the AlxGa1−xN layer to connect internally to the 2D plane, parallel conduction through this layer is a feature of all modulation-doped devices. The …


Unusual Luminescence Lines In Gan, M. A. Reshchikov, D. Huang, F. Yun, P. Visconti, L. He, H. Morkoç, J. Jasinski, Z. Liliental-Weber, R. J. Molnar, S. S. Park, K. Y. Lee Jan 2003

Unusual Luminescence Lines In Gan, M. A. Reshchikov, D. Huang, F. Yun, P. Visconti, L. He, H. Morkoç, J. Jasinski, Z. Liliental-Weber, R. J. Molnar, S. S. Park, K. Y. Lee

Electrical and Computer Engineering Publications

A series of sharp intense peaks was observed in the low-temperature photoluminescence spectrum of unintentionally doped GaN in the photon energy range between 3.0 and 3.46 eV. We attributed the majority of these peaks to excitons bound to unidentified structural and surface defects. Most of the structural- and surface-related peaks (at 3.21, 3.32, 3.34, 3.35, 3.38, and 3.42 eV) were observed in Ga polar films. In N polar GaN, we often observed the 3.45 eV peak attributed to excitons bound to the inversion domain interfaces.


Contactless Electroreflectance, In The Range Of 20 K < T < 300 K, Of Freestanding Wurtzite Gan Prepared By Hydride-Vapor-Phase Epitaxy, Y. S. Huang, Fred H. Pollak, S. S. Park, K. Y. Lee, H. Morkoç Jan 2003

Contactless Electroreflectance, In The Range Of 20 K < T < 300 K, Of Freestanding Wurtzite Gan Prepared By Hydride-Vapor-Phase Epitaxy, Y. S. Huang, Fred H. Pollak, S. S. Park, K. Y. Lee, H. Morkoç

Electrical and Computer Engineering Publications

We have performed a detailed contactless electroreflectance study of the interband excitonic transitions on both the Ga and N faces of a 200-μm-thick freestanding hydride-vapor-phase-epitaxy grown wurtzite GaN sample with low defect concentration in the temperature range between 20 and 300 K. The transition energies of the A, B, and C excitons and broadening parameters of the A and B excitons have been determined by least-square fits to the first derivative of a Lorentzian line shape. The energy positions and separations of the excitonic transitions in the sample reveal the existence of residual strain. At 20 K the broadening parameter …