High-performance self-powered UV photodetector based on CuI/CsCu2I3/GaN heterojunction

• High-quality Cu-based perovskite CsCu 2 I 3 thin films were grown on GaN substrates. • The type-II heterojunction photodetector based on CuI/CsCu 2 I 3 /GaN was fabricated. • The photodetector can realize self-powered detection. • The photodetector has high on/off ratios of 97886 (UV) and 31255 (red) at 0 V. Self-powered ultraviolet (UV) photodetectors have far-reaching applications in the nanoelectronics. In this work, nontoxic copper halide perovskite CsCu 2 I 3 thin films were grown by vacuum thermal evaporation method on n-GaN substrates. The p-CuI/CsCu 2 I 3 /n-GaN heterojunction photodetectors exhibit obvious sensitivity and self-powered characteristics in the ultraviolet (∼365 nm) narrowband. The device exhibits excellent reproducibility and a high on/off ratio of 97,886 under zero bias voltage. Furthermore, under UV illumination, the responsivity, specific detectivity, and external quantum efficiency reach 71.7 mA/W, 3.3 × 10 12 Jones, and 26.1% at 0 V bias, respectively. The result provides a new strategy to design a highly integrated monolithic device for self-powered detection