Umesh K. Mishra
University of California, Santa Barbara
929 Papers
10.5K Citations
Umesh K. Mishra is an academic researcher from University of California, Santa Barbara. The author has contributed to research in topics: Gallium nitride & High-electron-mobility transistor. The author has an hindex of 96, co-authored 912 publications. Previous affiliations of Umesh K. Mishra include North Carolina State University & University of California.
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Papers
Selective area epitaxy of GaN for electron field emission devices
D. Kapolnek,Robert D. Underwood,Bernd Keller,Sarah L. Keller,Steven P. DenBaars,Umesh K. Mishra +5 more
TL;DR: In this paper, the area epitaxy of GaN by MOCVD has been used to fabricate arrays of hexagonal pyramid structures for electron field emission devices, and the reactor temperature and pressure have been found to strongly affect the resulting pyramid morphology.
Electron mobility in graded AlGaN alloys
TL;DR: In this article, the electron mobility in AlGaN alloys as a function of the alloy composition was analyzed and local bulk mobility values for different Alloy compositions were found, and electron mobility was deduced.
N-Polar GaN/AlN MIS-HEMT for Ka-Band Power Applications
Nidhi,Sansaptak Dasgupta,Yi Pei,Brian L. Swenson,Stacia Keller,James S. Speck,Umesh K. Mishra +6 more
TL;DR: In this paper, the authors demonstrate the millimeter-wave power performance from N-polar GaN-based metal-insulator-semiconductor high-electron-mobility transistors.
Interfacial N Vacancies in Ga N /( Al , Ga ) N / Ga N Heterostructures
Vera Prozheeva,Ilja Makkonen,Haoran Li,Stacia Keller,Umesh K. Mishra,Filip Tuomisto,Filip Tuomisto +6 more
TL;DR: In this article, it was shown that the occurrence of high interfacial vacancy concentrations is a universal property of nitride semiconductor heterostructures at net negative polarization interfaces, and that these vacancies are responsible for the trapping of holes observed in unoptimized high electron mobility transistors.