In recent years, low-dimensional semiconductors have attracted widespread attention in the field of next-generation broadband infrared photodetectors due to their tunable band structures, strong light-matter interactions, and compatibility with mixed-dimensional integration. Among them, tellurium (Te) and bismuth selenide (Bi2O2Se) have become ideal candidate materials for high-performance detection due to their inherent anisotropy, high carrier mobility, and broad spectral response. Constructing heterojunction photodetectors based on these materials can achieve self-powered operation and suppress dark current. Heterojunction interface engineering and band structure design capabilities are crucial for constructing high-performance Te/Bi2O2Se heterojunction photodetectors. Therefore, we in situ construct a 1D Te/2D Bi2O2Se heterojunction by a two-step chemical vapor deposition method, which shown a clear interface and type-II band alignment structure. Therefore, the photodetector based on Te/Bi2O2Se heterojunction working in self-driven mode exhibits high performance, showing a high responsivity of ~ 0.89 A·W-1 and a fast response time of ~ 29/41 μs under 1550 nm light irradiation. Further, owing to the optical absorption anisotropy of tellurium, the device exhibited a high polarization ratio of 2.8 and successfully demonstrated polarization optical communication and polarization imaging applications. This work provides new ideas for the in-situ construction strategy of high-quality mixed-dimensional van der Waals heterojunctions and the research on high-performance photodetectors and their applications.
Shang et al. (Sun,) studied this question.