Tunable photoresponse properties of CuI/Si self-powered photodetectors through Zn doping engineering

Zn doping engineering was achieved in copper iodide (CuI) films for CuI/Si heterojunction ultraviolet (UV) photodetectors (PDs) by employing a facile solution approach. The morphology, grain sizes and optical properties of CuI films with various Zn²⁺ doping concentrations are systematically investigated. Our results indicate that an appropriate Zn doping concentration can significantly improve the quality of CuI thin films, leading to an improved photodetection performance, while an excessive amount of Zn dopant can cause poor interface and quality of CuI films. The optimized Zn-doped CuI/Si UV PD exhibited remarkable photodetection performance with a high responsivity of 0.561 A/W at 0 V bias, surpassing all reported CuI-based photodetectors.