Ultrasensitive fully transparent amorphous Ga2O3 solar-blind deep-ultraviolet photodetector for corona discharge detection

Solar-blind deep-ultraviolet photodetectors are one of the most effective tools to detect corona discharge because high-voltage corona discharge is always accompanied by deep-ultraviolet light (UVC, 200–280 nm), referred to as solar-blind signals. In this study, a fully transparent metal-semiconductor-metal solar-blind photodetector with Al-doped ZnO (AZO) transparent electrodes was successfully constructed based on amorphous Ga2O3 film (a-Ga2O3) and prepared by radio frequency magnetron sputtering. The as-fabricated fully transparent device exhibits excellent performance, including an ultra-low dark current of 2.84 pA, a high photo-to-dark current ratio of 1.41 × 107, superb rejection ratio (R254/R400 = 2.93 × 105), a large responsivity of 2.66 A W−1, superb detectivity (4.84 × 1014 Jones), and fast response speed (rise/fall time: 24 μs/1.24 ms). It is worth noting that the fully transparent a-Ga2O3 photodetector demonstrates ultra-high sensitivity to weak solar-blind signals, far below the 100 nW cm−2 threshold of the test equipment. It also has high-resolution detection capabilities for subtle changes in radiation intensity. Acting as a sensor for the high-voltage corona discharge simulation detection system, the fully transparent a-Ga2O3 photodetector can clearly detect extremely weak solar-blind signals. The results described in this work serve as proof-of-concept for future applications of amorphous Ga2O3 solar-blind deep-ultraviolet photodetectors in high-voltage corona discharge detection.