In this study, a high-photoresponsivity self-powered deep ultraviolet (DUV) photodetector based on an Ag2O/β-Ga2O3 heterojunction was fabricated by depositing a p-type Ag2O thin film onto an n-type β-Ga2O3 layer. The device characteristics after post-annealing at temperatures ranging from 0 to 400 °C were investigated. Our DUV devices exhibited typical rectification characteristics. At a post-annealing temperature of 300 °C, the as-fabricated device had a low leakage current of 4.24 × 10-11 A, ideality factor of 2.08, and a barrier height of 1.12 eV. Moreover, a high photo-responsivity of 12.87 mA/W was obtained at a 100 μW/cm2 light intensity at a 254 nm wavelength at zero bias voltage, the detectivity was 2.70 × 1011 Jones, and the rise and fall time were 29.76, 46.73 ms, respectively. Based on these results, the Ag2O/β-Ga2O3 heterojunction photodetector operates without an externally applied voltage and has high responsivity, which will help in the performance improvement of ultraviolet sensing systems.
Keywords: Ag2O/β-Ga2O3; deep ultraviolet; heterojunction; photodetector; post-annealing.