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

Abstract In this study an (Al x Ga 1‐x ) 2 O 3 barrier layer is inserted between β ‐Ga 2 O 3 and GaN in a p‐GaN/n‐Ga 2 O 3 diode photodetector, causing the dark current to decrease considerably, and device performance to improve significantly. The β ‐Ga 2 O 3 / β ‐(Al x Ga 1‐x ) 2 O 3 /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 × 10 15 cm Hz 1/2 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 Ga 2 O 3 . This study also proposes an effective way to suppress persistent photoconductivity and significantly increase the device operation speed in photodetectors fabricated from Ga 2 O 3 through the light‐induced neutralization of STHs.