ZnO 纳米棒/Bi₂S₃量子点异质结的制备及光电探测性能研究

In order to obtain a ZnO-based broadband photodetector with a multi-band response, ZnO is coupled with other narrow-bandgap semiconductors to construct the heterojunction. In this study, ZnO nanorod（NR）arrays were first grown on FTO substrate through the hydrothermal process. Then, Bi₂S₃ quantum dots（QDs）were synthesized on the surface of ZnO NRs via the successive ionic layer absorption reaction method, thereby successfully constructing the ZnO NRs/Bi₂S₃ QDs heterojunction. The micro-morphology and elemental composition of as-prepared samples were characterized using a scanning electron microscope and energy dispersive spectrometer. The results show that the Bi₂S₃ QDs are uniformly and densely attached to the surface of ZnO NRs that are slightly curved and partially intertwined at the top. Then, a broadband photodetector was fabricated based on the as-prepared heterojunction. In addition, the photodetector based on the ZnO NRs/Bi₂S₃ QDs heterojunction can operate without an external power source, indicating that the photodetector has a self-powered feature. Compared with the ZnO NRs photodetector, the maximum photocurrent of the ZnO NRs/Bi₂S₃ QDs photodetector under UV light irradiation increases by approximately 0. 065 mA. This is mainly because the type II band alignment between ZnO and Bi₂S₃ increases the separation efficiency of photogenerated charge carriers. Furthermore, the ZnO NRs/Bi₂S₃ QDs photodetector has excellent detection capability for visible light, exhibiting excellent cycle stability when irradiated by blue（470 nm）and green light（530 nm）.