Strategy of All-Inorganic Cs<sub>3</sub>Cu<sub>2</sub>I<sub>5</sub>/Si-Core/Shell Nanowire Heterojunction for Stable and Ultraviolet-Enhanced Broadband Photodetectors with Imaging Capability
Wenqing Liang, Zhifeng Shi, Ying Li, Jingli Ma, Shuting Yin, Xu Chen, Di Wu, Yongzhi Tian, Yongzhi Tian, Yongtao Tian, Yongtao Tian, Yù Zhang, Xinjian Li, Chongxin Shan
Abstract
In this study, for the first time, the integration of nontoxic ternary copper halide Cs3Cu2I5 with one-dimensional Si nanowires (NWs) was reported to achieve an ultraviolet (UV)-enhanced Si NW broadband photodetector. A compact and uniform coverage of Cs3Cu2I5 on the top and sidewall of Si NWs formed a core/shell heterostructure, in which Si NWs served as the growth template and the electron-transport layer, and Cs3Cu2I5 was employed as the UV photoactive material and the hole-transport layer. The as-fabricated Cs3Cu2I5/Si-core/shell NW photodetector demonstrates a multiband photodetection from the deep UV to near-infrared region, a fast response speed of 92.5/189.2 μs (265 nm), and a high photoresponsivity of 130 mA/W, nearly 600 times as much as the reference device constructed using Si NWs. More importantly, the proposed photodetector exhibits an excellent stability in air ambient. Typically, it could endure a high temperature of 60 °C for 11 h consecutive working; after storage in air ambient for two weeks, its photodetection ability can almost be retained. Additionally, high-resolution UV imaging applications were presented by employing the proposed photodetector as sensing pixels. These obtained results verify the effectiveness of the Cs3Cu2I5/Si-core/shell NW heterojunction strategy for UV-enhanced broadband photodetection, making such a device really possible for practical applications.