Thermal oxidation-enabled β-Ga₂O₃/GaN heterojunction for broadband self-powered UV detection

We report a self-powered broadband UV photodetector based on a β-Ga₂O₃/GaN heterojunction formed via one-step thermal oxidation. The device exhibits high responsivities of 153.9 mA/W (254 nm, 300 μW/cm², 0 V) and 52.3 mA/W (365 nm, 300 μW/cm², 0 V), with excellent detectivity (1.25 × 10¹² Jones) and fast response (189 ms/96 ms). The type-I band alignment and low interfacial trap density enable efficient carrier separation. Single-pixel imaging of characters and patterns under UVA and UVC illumination further demonstrates its application potential. This work provides a viable route for high-performance, self-powered broadband UV photodetectors using thermal oxidation.