A deep-ultraviolet photodetector of a β-Ga2O3/CuBiI4 heterojunction highlighting ultra-high sensitivity and responsivity

Herein, a β-Ga2O3/CuBiI4 heterojunction deep-ultraviolet (DUV) photodetector was constructed based on metal-organic chemical vapor deposition grown β-Ga2O3 film and spin-coated CuBiI4 film. In which, we prepared the pure and well-crystallized CuBiI4 film from environment-friendly materials under optimized experimental conditions. The fabricated device exhibited a large responsivity of 20.68 A/W, a high specific detectivity of 3.72 × 1015 Jones, a high photo-to-dark current ratio of 5.62 × 106, a low dark current of 0.385 pA, and an ultrahigh UV/visible rejection ratio (R250 nm/R400 nm) of 1.14 × 104 under 254 nm UV light illumination at 5 V. In all, the device can sensitively monitor a wide range of UV light (254 nm) intensities from 0.1 to 2000 μW/cm2. Moreover, the potential of the device operating under self-powered mode has been verified, and the intrinsic physical mechanism of the heterojunction photodetector was analyzed via energy-band alignment. Overall, this work would present a promising route to realize high-performance and cost-effective DUV photodetector.