High responsivity of GaN p-i-n photodiode by using low-temperature interlayer

Abstract

Gallium nitride p-i-n ultraviolet photodiodes with low- temperature (LT)- GaN interlayer have been fabricated. It was found that the dark current of photodiode with LT- GaN interlayer is as small as 143 pA at 5 V reverse bias. It was also found that the responsivity of the photodiode with LT- GaN interlayer can be enhanced at a small electric field (similar to 0.4 MV/cm) due to the carrier multiplication effect. The UV photocurrent gain of 13 and large ionization coefficient (alpha = 3.1 X 10(5) cm(-1)) were also observed in the detector with LT- GaN interlayer. Furthermore, we can achieve a large peak responsivity of 2.27 A/W from the photodiode with LT- GaN interlayer. (C) 2007 American Institute of Physics.