He Zhao, Qiyin Wang, Man Zhao, Dayong Jiang, QingCheng Liang
Si‐based ZnO is a promising photodetector material because of its low cost and ease of integration. However, selective tuning of the response spectrum remains challenging. In this study, MgO was introduced as a barrier layer based on a metal–semiconductor–metal structure. A p‐Si/MgO/ZnO device was prepared, leading to the realization of a bias‐modulated dual‐frequency response operating mode. The p‐Si carrier jump was suppressed at a bias voltage of 1 V, and the photodetector performed well at a wavelength of 365 nm, achieving a responsivity and external quantum efficiency of 0.46 A W −1 and 155%, respectively. The carriers in p‐Si gain sufficient kinetic energy to achieve tunneling at 5 V; the probability of lattice collisions increases, thereby more readily triggering the multiplication effect. The response range of the detector was expanded to include the ultraviolet, visible, and near infrared regions, obtaining responsivity of 2.24, 0.48, and 0.88 A W −1 , respectively. The structure exhibited a unique dual‐frequency probing performance under bias modulation, and it was applied in dual‐mode imaging, laying the foundation for the development of third‐generation imaging technology.