Projects per year
We show that N-polar GaN/(Al,Ga)N/GaN heterostructures exhibit significant N deficiency at the bottom (Al,Ga)N/GaN interface, and that these N vacancies are responsible for the trapping of holes observed in unoptimized N-polar GaN/(Al,Ga)N/GaN high electron mobility transistors. We arrive at this conclusion by performing positron annihilation experiments on GaN/(Al,Ga)N/GaN heterostructures of both N and Ga polarity, as well as state-of-the-art theoretical calculations of the positron states and positron-electron annihilation signals. We suggest that the occurrence of high interfacial N vacancy concentrations is a universal property of nitride semiconductor heterostructures at net negative polarization interfaces.
01/09/2018 → 22/09/2019
Project: Academy of Finland: Other research funding
Prozheeva, V., Makkonen, I., Li, H., Keller, S., Mishra, U. K., & Tuomisto, F. (2020). Interfacial N Vacancies in GaN/(Al,Ga)N/GaN Heterostructures. Physical Review Applied, 13(4), 1-7. . https://doi.org/10.1103/PhysRevApplied.13.044034