Self-powered photodetector with low dark current based on the InSe/β-Ga2O3 heterojunctions

Solar-blind photodetectors play an important role in many fields of solar-blind ultraviolet (UV) photodetection such as missile tracking and fire warning. A high-performance self-powered solar-blind photodetector was fabricated using InSe/β-Ga₂O₃ heterojunction. The 4-inch wafer-scale β-Ga₂O₃ film was prepared by a low-cost sol–gel process. The resulting β-Ga₂O₃ film was flat and uniform with an RMS (Root Mean Square roughness) of 1.08 nm. A self-driven solar-blind UV photodetector of InSe/β-Ga₂O₃ was constructed by stacking an InSe flake with a wide wavelength range of 230 nm to 800 nm. This detector could detect 230 nm deep UV under zero bias with a very small response dark current (3.98 fA) and a responsivity of about 122.69 μA W⁻¹. These impressive results demonstrate the potential of the 4-inch polycrystalline-oriented β-Ga₂O₃ for light-conducting photovoltaic devices.