Enhanced Performance of Self-Powered Solar-Blind Deep UV Photodetectors Based on ZnGa₂O₄/Ga₂O₃ Heterojunctions

Abstract

Self-powered UV photodetectors (PDs) attract much research attention because of their promising application in solar-blind region detection. Here, a high-performance self-powered PD is constructed using the heterojunction of Ga ₂ O ₃ and ZnGa ₂ O ₄ . Taking advantage of the low concentration of oxygen vacancies (V _o ) in ZnGa ₂ O ₄ and the photovoltaic effect at the interface, the PD demonstrates inspiring solar-blind ultraviolet (UV) photodetection capabilities. Under external bias (5 V), the ZnGa ₂ O ₄ /Ga ₂ O ₃ heterojunction PD exhibits an ultra-low dark current of 0.06 pA, a high photo-dark current ratio (PDCR) of 9.39 × 10 ⁵ , and a rapid response speed. In the self-powered mode (0 V), the PD demonstrates a significant photovoltaic effect, which is characterized to have an open-circuit voltage of 0.14 V. Additionally, it exhibits enhanced photoresponse with PDCR of approximately 10 ⁴ (500 μW/cm ² ). Our findings suggest that ZnGa ₂ O ₄ /Ga ₂ O ₃ heterojunction PDs can potentially become a highly efficient and energy-saving option for solar-blind detection in the future.