Broadband Photodetector Based on FePS₃/WS₂ van der Waals Type II Heterostructure

In order to understand broadband photodetectors from ultraviolet-visible (UV-vis) to the near-infrared range, one needs to find novel two-dimensional (2D) van der Waals (vdW) materials with broadband optoelectronic performance. Transition metal phosphorus sulfides (TMPSs) have been reported as a new type of vdW material with generally broadband and p-type conductivity. Here, we report a high-performance and broadband photodetector consist of p-type FePS₃ and n-type WS₂ with a working range of 405-785 nm. The maximum values of responsivity and specific detectivity are 32.5 mA/W and 1.73 × 10¹² jones at 405 nm and 2 V bias, which are better than those of its individual constituents and many other 2D vdW heterostructures. The high performance of the FePS₃/WS₂ photodetector is attributed to the built-in electric field in the FePS₃/WS₂ p-n heterostructure and type II band alignment. Present study demonstrates that the material family of TMPSs could be a promising platform for broadband photodetector applications.