Tellurium/Bismuth Selenide van der Waals Heterojunction for Self‐Driven, Broadband Photodetection and Polarization‐Sensitive Application

Abstract Broadband detection technology is crucial in the fields of astronomy and environmental surveying. Two dimensional (2D) materials have emerged as promising candidates for next‐generation broadband photodetectors with the characteristics of high integration, multi‐dimensional sensing, and low power consumption. Among these, 2D tellurium (Te) is particularly noteworthy due to its excellent mobility, tunable bandgap, and air stability. However, the performance of the Te‐based photodetector has been hindered by high dark current and cut‐off wavelength limitations associated with its intrinsic bandgap. Here, the Te / bismuth selenide (Bi 2 Se 3 ) van der Waals (vdWs) p‐n heterojunction with a clean interface and type‐II band alignment, designed to address these challenges are presented. The Te/Bi 2 Se 3 heterojunction photodetectors demonstrate an ultra‐broadband photodetection range from Ultraviolet (UV) to Mid‐infrared (MIR) (365 nm–4.3 µm) and a high responsivity up to 880 mA W −1 at 1550 nm under zero bias. Moreover, benefiting from the anisotropy crystal structure of Te, the photodetector shows an obvious polarization‐sensitive photoresponse and enormous potential in optical communication and polarization imaging. This work hereby provides significant insight into low‐powered, high‐performance, and broadband vdWs heterojunction photodetectors and their functional applications.