Type‑I Heterostructure\nBased on WS₂/PtS₂ for High-Performance Photodetectors

Abstract

van der Waals (vdW) heterodiodes composed of two-dimensional\n(2D)\nlayered materials led to a new prospect in photoelectron diodes and\nphotovoltaic devices. Existing studies have shown that Type-I heterostructures\nhave great potential to be used as photodetectors; however, the tunneling\nphenomena in Type-I heterostructures have not been fully revealed.\nHerein, a highly efficient nn⁺ WS₂/PtS₂ Type-I vdW heterostructure photodiode is constructed. The device\nshows an ultrahigh reverse rectification ratio of 10⁵ owing\nto the transmission barrier-induced low reverse current. A unilateral\ndepletion region is formed on WS₂, which inhibits the recombination\nof carriers at the interface and makes the external quantum efficiency\n(EQE) of the device reach 67%. Due to the tunneling mechanism of the\ndevice, which allows the co-existence of a large photocurrent and\na low dark current, this device achieves a light on/off ratio of over\n10⁵. In addition, this band design allows the device to\nmaintain a high detectivity of 4.53 × 10¹⁰ Jones.\nOur work provides some new ideas for exploring new high-efficiency\nphotodiodes.