Type-I Heterostructure Based on WS<sub>2</sub>/PtS<sub>2</sub> for High-Performance Photodetectors
Zihan Wang, Hui Zhang, Weike Wang, Chaoyang Tan, Jiawang Chen, Shiqi Yin, Hanlin Zhang, Ankang Zhu, Gang Li, Yuchen Du, Shaotian Wang, Fengguang Liu, Liang Li
Abstract
van der Waals (vdW) heterodiodes composed of two-dimensional (2D) layered materials led to a new prospect in photoelectron diodes and photovoltaic devices. Existing studies have shown that Type-I heterostructures have great potential to be used as photodetectors; however, the tunneling phenomena in Type-I heterostructures have not been fully revealed. Herein, a highly efficient nn+ WS2/PtS2 Type-I vdW heterostructure photodiode is constructed. The device shows an ultrahigh reverse rectification ratio of 105 owing to the transmission barrier-induced low reverse current. A unilateral depletion region is formed on WS2, which inhibits the recombination of carriers at the interface and makes the external quantum efficiency (EQE) of the device reach 67%. Due to the tunneling mechanism of the device, which allows the co-existence of a large photocurrent and a low dark current, this device achieves a light on/off ratio of over 105. In addition, this band design allows the device to maintain a high detectivity of 4.53 × 1010 Jones. Our work provides some new ideas for exploring new high-efficiency photodiodes.