Self-powered solar blind ultraviolet photodetector based on amorphous (In_0.23Ga_0.77)₂O₃/bixbyite (In_0.67Ga_0.33)₂O₃ heterojunction

Self-powered solar-blind ultraviolet photodetectors are considered for potential applications in secure communication and space detection. However, high-quality p-type wide bandgap semiconductors are nonexistent due to the self-compensation effect, which makes the design of p-n homojunction photodetectors a challenging proposition to date. In this work, a self-powered solar-blind ultraviolet photodetector is fabricated and discussed, based on a novel heterojunction of (In_xGa_1−x)₂O₃ ternary alloy films with two different compositions, which has a flexible design and can be easily fabricated for different applications. The heterojunction consists of an amorphous (In_0.23Ga_0.77)₂O₃ on the top of a bixbyite (In_0.67Ga_0.33)₂O₃ film prepared by radio frequency magnetron sputtering. The amorphous (In_0.23Ga_0.77)₂O₃/bixbyite (In_0.67Ga_0.33)₂O₃ heterojunction photodetector exhibits a responsivity of 5.78 mA/W, a detectivity of 1.69 × 10¹¹ cm Hz^1/2 W⁻¹, and a high solar-blind UV (248 nm)/visible light (450 nm) rejection ratio of 1.39 × 10³ at zero bias, suggesting decent spectral selectivity and high performance. The responsivity and peak wavelength of this photodetector can be tuned by the film thickness of the amorphous (In_0.23Ga_0.77)₂O₃. This work provides a new design for self-powered solar-blind UV detectors based on ternary alloy heterojunctions.