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

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 (BiSe) 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/BiSe 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 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.