Highly Photosensitive and Stable SiC/ZnO Nanowire Photoelectrochemical Ultraviolet Photodetector Based on Heterojunction Engineering for Reliable Complex Underwater Application

Abstract The precise tailoring of bandgap structures as well as carrier separation and transport behavior via heterojunction engineering can provide a practical and viable pathway for enhancing the performance of low‐dimensional semiconductor devices. In this study, a highly photosensitive photoelectrochemical (PEC) ultraviolet (UV) photodetector (PD) based on a SiC/ZnO heterojunction is explored. The surfaces of SiC nanowires are successfully modified using high‐quality ZnO nanospheres via a simple hydrothermal process. The as‐constructed SiC/ZnO heterojunction nanowire PEC UV PD achieves high photodetection performance—high responsivity (15.76 mA W ⁻¹ ), high detectivity (1.827 × 10 ¹⁰ Jones), excellent external quantum efficiency (5.21%), and fast rise/decay times (186/454 ms), under 375‐nm UV illumination. Remarkably, the device exhibits a high photoresponse under different solution concentrations, temperature conditions, and excellent aging stability over long‐term operation. Its highly sensitive and reliable photodetection performance could be attributed primarily to the synergy among the type‐II charge transfer pathways formed at the SiC/ZnO heterojunction, enhanced photogenerated‐carrier separation efficiency, and improved light–matter interactions enabled by the large specific surface area of the ZnO nanospheres. Overall, this study establishes a paradigm for developing highly sensitive PEC PDs suitable for optical communication under harsh underwater conditions, thereby advancing heterojunction and interfacial engineering strategies for next‐generation optoelectronics.