Broadband Ultraviolet Photodetector Based on GaN/β-Ga2O3 pn Heterojunction with Graphene

Broadband ultraviolet (BUV) photodetectors are widely used in military and civil fields. In this paper, a high performance BUV photodetector based on GaN/β-Ga 2 O 3 pn-heterojunction with graphene is proposed, where the graphene was employed as a transparent electrode. The fabricated photodetector exhibits a series of excellent performance, including extremely low dark current (14nA), a broad response band from 212 nm to 372 nm with responsivity exceeding 1 A/W at -5 V bias voltage and a peak responsivity of 6.64 A/W at 252 nm. These excellent performances can be attributed to the internal gain mechanism of the GaN/β-Ga 2 O 3 pn-heterojunction and the optical properties of graphene. The transient response of the device to 254 nm and 365 nm LED illumination at -5 V bias is found to be less than 100 ms. Our work provides an effective method to realize a high-performance BUV photodetector for photoelectric applications.