Interface-Engineered High-Performance Self-Powered Solar-Blind Photodetector Based on NiO/ε-Ga₂O₃ Heterojunctions

Self-powered solar-blind photodetectors based on Ga 2 O 3 heterojunctions with high sensitivity and fast response speeds are in high demand for versatile applications. However, the inferior assembly of the heterojunction interface typically results in a significant leakage current and compromised device performance. Herein, we fabricate a NiO/ε-Ga 2 O 3 p–n heterojunction solar-blind photodetector for the first time and introduce a high-resistance homogeneous layer at the interface to suppress the leakage current successfully. The high-resistance layer serves to extend the depletion region and thereby reduce the probability of tunneling, which enhances the separation efficiency of photogenerated carriers and inhibits the leakage current. Consequently, the photodetector with comprehensively enhanced performance exhibits a notable responsivity of 160 mA/W, a remarkable detectivity of 3.7 × 10 12 Jones, and a fast response speed, with a rise time of 38 ms and a decay time of 67 ms at zero bias, which is superior to previous studies based on β-Ga 2 O 3 in the field of self-powered solar-blind photodetectors. This work provides a reliable strategy for developing advanced Ga 2 O 3 -based optoelectronic devices.