An enhanced ultrasensitive solar-blind UV photodetector based on an asymmetric Schottky junction designed with graphene/β-Ga2O3/Ag

Abstract

Ga₂O₃ has generated considerable interest as a wide bandgap semiconductor and is used for solar-blind deep ultraviolet photodetectors. Additionally, graphene serving as a transparent electrode material can improve device performance. However, due to defects at the contact interface between graphene and Ga₂O₃, existing devices based on graphene/Ga₂O₃ are liable to elevated dark currents. In this work, we constructed a graphene/β-Ga₂O₃/Ag asymmetric Schottky junction photodetector, which addresses this issue. Taking advantage of the asymmetric structure design to suppress dark current and the transparent graphene electrode increasing the carrier collection efficiency, the device achieved an outstanding responsivity of 44.09 A W⁻¹, a high detectivity of 5.84 × 10¹² Jones, a remarkable external quantum efficiency of 2.15 × 10⁴%, and a fast response time of 99.60 ms/27.74 ms. More importantly, owing to reverse bias voltage on the high barrier side, it possesses a low dark current of 12.09 pA with a light-to-dark ratio of up to 10⁴. All in all, the graphene/β-Ga₂O₃/Ag asymmetric Schottky junction photodetector has considerable potential as a deep ultraviolet detector.