Solar-Blind Ultraviolet Photodetectors, Focal Plane Arrays, and Visible-Blind Avalanche Photodiodes.

摘要

This thesis highlights the progression of the development of III-Nitride based high-efficiency back-illuminated solar-blind ultraviolet photodetectors, solar-blind focal plane arrays and visible-blind avalanche photodiodes. The discussion on design considerations, material growth-characterization, fabrication-processing and measurement results are provided in this report.;The devices realized in this work demonstrated quantum efficiency that is among the highest ever reported for a back-illuminated solar-blind photodetector (responsivity of 196 mA/W at 275nm, external quantum efficiency (EQE) of 89%). Taking advantage of the back illuminated nature of these detectors, we have successfully developed the technology to hybridize and test a solar-blind focal plane array camera. The optimized focal plane array imager showed good uniformity (with median 57% EQE) and 92% operability, and several images from UV cameras are reported here.;For III-Nitride based devices to effectively operate under low incident photon flux, it is necessary to improve the signal to noise ratio. To this end, GaN-based avalanche photodiodes (APDs), with internal gain, have been studied. We report here the first realization of a visible-blind top-illuminated avalanche photodiode grown on m- and c-plane GaN substrate. In liner mode; APDs showed gain of ∼14000 whereas in Geiger mode APDs showed single photon detection efficiency of ∼30.5%.