High Gain beta-Ga2O3 Solar-Blind Schottky Barrier Photodiodes via Carrier Multiplication Process

Abstract

beta-Ga2O3, which is a ultra-wide band-gap semiconductor, is an attractive material for next-generation solar-blind photodetectors. A high gain solar-blind Schottky barrier photodetector using an exfoliated single crystalline beta-Ga2O3 nano-layer was demonstrated by employing internal carrier multiplication process. Excellent spectral selectivity with high responsivity was obtained between UV-A and UV-C wavelengths with fast response/decay characteristics. The gain of our beta-Ga2O3 solar-blind PD was similar to 3.78 x 10(3) under the multiplication mode at the reverse bias of -60 V, where the peak electric field was estimated to be 4.3 MV/cm (equivalent to impact ionization coefficient of 5 x 10(3) cm(-1)). Compared with non-multiplication mode, outstanding photo-sensing performances were achieved under the multiplication mode, including a responsivity of 8.18 A/W, a photocurrent-to-dark-current ratio of similar to 10(3) and external quantum efficiency of similar to 4 x 10(3)%. High gain via carrier multiplication process in a beta-Ga2O3 photodiode proposes a new route toward high performance solar-blind deep-UV photodetectors. (c) 2018 The Electrochemical Society.