GaN Schottky barrier photodetectors with multi-MgN/GaN buffer

GaN Schottky barrier photodetectors (PDs) separately prepared with a conventional single low-temperature (LT) GaN buffer layer and a multi-MgN/GaN buffer layer were both fabricated. It was found that we could reduce threading dislocation (TD) density and thus improve crystal quality of the GaN PDs by using the multi-MgN/GaN buffer layer. With a 2 V reverse bias, it was found that the reverse leakage currents measured from PDs with single LT GaN buffer layer and that with multi-MgN/GaN buffer layer were 4.57times10^-6 and 1.44times10^-12 A, respectively. It was also found that we could use the multi-MgN/GaN buffer layer to suppress photoconductive gain, enhance UV-to-visible rejection ratio, reduce noise level and enhance the detectivity.