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

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 143pA at 5V reverse bias. It was also found that the responsivity of the photodiode with LT-GaN interlayer can be enhanced at a small electric field (∼0.4MV∕cm) due to the carrier multiplication effect. The UV photocurrent gain of 13 and large ionization coefficient (α=3.1×105cm−1) were also observed in the detector with LT-GaN interlayer. Furthermore, we can achieve a large peak responsivity of 2.27A∕W from the photodiode with LT-GaN interlayer.