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Your search keyword '"Shirazi-HD, M."' showing total 6 results
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6 results on '"Shirazi-HD, M."'

1. Terahertz intersubband absorption in non-polar m-plane AlGaN/GaN quantum wells

Author

Edmunds, C., Shao, J., Shirazi-HD, M., Manfra, M. J., and Malis, O.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We demonstrate THz intersubband absorption (15.6-26.1 meV) in m-plane AlGaN/GaN quantum wells. We find a trend of decreasing peak energy with increasing quantum well width, in agreement with theoretical expectations. However, a blue-shift of the transition energy of up to 14 meV was observed relative to the calculated values. This blue-shift is shown to decrease with decreasing charge density and is therefore attributed to many-body effects. Furthermore, a ~40% reduction in the linewidth (from roughly 8 to 5 meV) was obtained by reducing the total sheet density and inserting undoped AlGaN layers that separate the wavefunctions from the ionized impurities in the barriers.

Published
2014
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3. Kinetic instability of AlGaN alloys during MBE growth under metal-rich conditions on m-plane GaN miscut towards the -c axis.

Author

Shirazi-HD, M., Diaz, R. E., Nguyen, T., Jian, J., Gardner, G. C., Wang, H., Manfra, M. J., and Malis, O.

Subjects
*ALUMINUM gallium nitride, *ALLOYS, *MOLECULAR beam epitaxy, *SCANNING transmission electron microscopy, *DIMERS
Abstract

AlxGa1-xN layers with Al-composition above 0.6 (0.6 < x < 0.9) grown under metal-rich conditions by plasma-assisted molecular beam epitaxy on m-plane GaN miscut towards the -c axis are kinetically unstable. Even under excess Ga flux, the effective growth rate of AlGaN is drastically reduced, likely due to suppression of Ga-N dimer incorporation. The defect structure generated during these growth conditions is studied with energy dispersive x-ray spectroscopy scanning transmission electron microscopy as a function of Al flux. The AlGaN growth results in the formation of thin Al(Ga)N layers with Al-composition higher than expected and lower Al-composition AlGaN islands. The AlGaN islands have a flat top and are elongated along the c-axis (i.e., stripe-like shape). Possible mechanisms for the observed experimental results are discussed. Our data are consistent with a model in which Al-N dimers promote release of Ga-N dimers from the m-plane surface. [ABSTRACT FROM AUTHOR]

Published
2018
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6. Comparative study of intersubband absorption in AlGaN/GaN and AlInN/GaN superlattices: Impact of material inhomogeneities

Author

Edmunds, C., primary, Tang, L., additional, Cervantes, M., additional, Shirazi-HD, M., additional, Shao, J., additional, Grier, A., additional, Valavanis, A., additional, Cooper, J. D., additional, Li, D., additional, Gardner, G., additional, Zakharov, D. N., additional, Ikonić, Z., additional, Indjin, D., additional, Harrison, P., additional, Manfra, M. J., additional, and Malis, O., additional

Published
2013
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