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

Abstract

β-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 β-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 β-Ga2O3 solar-blind PD was ∼3.78 × 103 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 × 103 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 ∼103 and external quantum efficiency of ∼4 × 103%. High gain via carrier multiplication process in a β-Ga2O3 photodiode proposes a new route toward high performance solar-blind deep-UV photodetectors.