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.

One of the most important applications of photodetectors is as sensing units in imaging systems. In practical applications, a photodetector array with high uniformity and high performance is an indispensable part of the imaging system. Herein, a photodetector array (5 × 4) consisting of 20 photodetector units, in which the photosensitive layer involves preprocessing commercial ε-Ga₂O₃ films with high temperature annealing, have been constructed by low-cost magnetron sputtering and mask processes. The ε-Ga₂O₃ ultraviolet photodetector unit shows excellent responsivity and detectivity of 6.18 A/W and 5 × 10¹³ Jones, respectively, an ultra-high light-to-dark ratio of 1.45 × 10⁵, and a fast photoresponse speed (0.14/0.09 s). At the same time, the device also shows good solar-blind characteristics and stability. Based on this, we demonstrate an ε-Ga₂O₃-thin-film-based solar-blind ultraviolet detector array with high uniformity and high performance for solar-blind imaging in optoelectronic integration applications.

Transparent conductive oxide (TCO) films are crucial in optoelectronic devices, such as photodetectors, due to their unique blend of transparency and electrical conductivity. ZnO is a top choice for TCOs owing to its excellent properties, non-toxicity, and cost-effectiveness. In this work, we explore the potential of carbon doping to enhance the electrical properties of ZnO films for transparent conductive applications. Our findings reveal that C-doped ZnO (ZnO:C) films retain the pristine high quality and surface morphology despite an increase in defects with higher C doping. Notably, C doping does not compromise the visible light transmittance of ZnO films, while inducing a gradual increase in optical bandgap, indicative of the typical Burstein–Moss effect. As carbon doping increases, the ZnO:C films exhibit improved carrier concentration, lower resistivity, and sustained high mobility, achieving optimal performance with an electron concentration of 3.73 × 1019 cm−3, resistivity of 3.69 × 10−3 Ω cm, and mobility of 46.08 cm2 V−1 s−1. Finally, we utilized ZnO:C films as a transparent electrode material in ε-Ga2O3-based photodetector, achieving the development of transparent device and attaining high-performance solar-blind detection capabilities. This work provides a strategy for developing a transparent conductive oxide, with ZnO:C emerging as a promising rival to IIIA-doped ZnO for optoelectronic applications.