High-Sensitivity Nitride-Based Ultraviolet Photosensors with a Low-Temperature AlGaN Interlayer

Abstract

Nitride-based ultraviolet (UV) photosensors with a low-temperature (LT) AlGaN interlayer were fabricated and characterized. Material analysis results showed that dark pits corresponding to threading dislocation (TD) terminations were almost invisible after inserting the LT AlGaN interlayer. It was also found that we could significantly suppress the dark leakage current by using the LT AlGaN interlayer owing to TD annihilation and demultiplication processes. For photosensors with the LT AlGaN interlayer, the responsivity at 360 nm and UV-to-visible rejection ratio were found to be 0.12 A/W and 2.45 9 10 3 , respectively, under 5 V applied bias.

GaN MSM UV Photodetectors with an Al0.82In0.18N Intermediate Layer

“…It should be noted that the maximum responsivity obtained from PD_B biased at À 5 V was much larger than the theoretical limit (i.e., the quantum efficiency was beyond 100%). 36 It has been shown that photoconductive gain in GaN PDs is originated from trapping of minority carriers by TDs. The trapped carriers will induce a bias-dependent "secondary current" and significantly reduce the operating speed of the PDs.…”