Ultrafast Self-Powered Solar-Blind Ultraviolet Photodetector Based on Ga2O3 Microwire/GaN p-n Heterojunction Using a Single-Layer Graphene as Electrode

Solar-blind ultraviolet photodetectors with high sensitivity and rapid photoresponse time are indispensable for practical applications in medical imaging diagnostics, military surveillance, advanced manufacturing, and other fields. This study presents a high-performance self-powered solar-blind ultraviolet photodetector, which is based on a Ga ₂ O ₃ microwire (MW)/GaN p-n heterojunction, with a single-layer graphene employed as the top electrode. The device showcases excellent rectification and photovoltaic characteristics, with an open-circuit voltage of 1.95 V, establishing it as a remarkable self-powered detector. When illuminated by a 265 nm light at 0 V bias, the device demonstrates a responsivity of 108.7 mA/W, a specific detectivity of 4.2×10 ¹² Jones, and an external quantum efficiency of 51.0%. Remarkably, the device exhibits an extremely fast response speed, with rise/recovery times of 88.2/85 μs, and the response bandwidth is estimated to be 3.5 kHz. Furthermore, our exploration of utilizing the detector as an optical data receiver in optical communications enabled to produce promising results, indicating its forward-looking applications for solar-blind ultraviolet detection. This study offers a simple and practical method for developing high-performance self-powered solar-blind ultraviolet photodetectors using low-dimensional Ga ₂ O ₃ single-crystals, providing valuable insights for advancing research in optoelectronic devices that function without external power sources.