High‐Performance Infrared Self‐Powered Photodetector Based on 2D Van der Waals Heterostructures

Abstract Self‐powered photodetection is an effective way to resolve the issue of high dark current in infrared photodetectors under a bias voltage. To date, high‐performance infrared self‐powered photodetectors (ISPDs) are mostly based on heterostructures consisting of 2D and 3D materials, while those based on 2D/2D heterostructures are rare. This will hinder the development of infrared devices toward miniaturization and energy‐saving. By exploring some 2D/2D van der Waals (vdWs) heterostructures, constructed by typical 2D transition metal dichalcogenides (TMDs), it is found that the heterostructure PdSe 2 /MoTe 2 is a high‐performance ISPD. It exhibits a good capability of self‐powered broadband detection from 300 to 1550 nm, even extending to 4050 nm. Especially, under near‐infrared illumination of 980 nm, its responsivity and detectivity can approach 395 mA W −1 and 1.92 × 10 11 Jones, respectively, which can be comparable with the high‐performance 2D/3D ISPDs. The heterostructure also possesses good environmental stability and infrared imaging capability. In addition, Three necessary conditions are proposed to construct 2D/2D high‐performance ISPD, i.e., a large difference of work function, high infrared absorption, and a type‐II band alignment. This work will guide a way to search for excellent ISPDs.