High Gain, Low Voltage Solar‐Blind Deep UV Photodetector Based on Ga2O3/(AlxGa1‐x)2O3/GaN nBp Heterojunction

Abstract

In this study an (AlxGa1‐x)2O3 barrier layer is inserted between β‐Ga2O3 and GaN in a p‐GaN/n‐Ga2O3 diode photodetector, causing the dark current to decrease considerably, and device performance to improve significantly. The β‐Ga2O3/β‐(AlxGa1‐x)2O3/GaN n‐type/Barrier/p‐type photodetector achieves a photocurrent gain of 1246, responsivity of 237 A W−1, and specific detectivity of 5.23 × 1015 cm Hz1/2 W−1 under a bias of −20 V. With the irradiation of 250 nm solar‐blind ultraviolet light, the photocurrent exhibits a dramatic nonlinear increase beyond a bias of ≈−4 V, attributed to interband electron tunneling. The onset of interband tunneling at a relatively low bias is due to the strong internal electric field formed by self‐trapped holes (STHs) in Ga2O3. This study also proposes an effective way to suppress persistent photoconductivity and significantly increase the device operation speed in photodetectors fabricated from Ga2O3 through the light‐induced neutralization of STHs.