High‐Performance Te‐Doped PbSe Film Heterojunction Photodetector with Current Rectification Effect and Broadband Detection Capability

Abstract PbSe has attracted wide attention owing to its fascinating physical and chemical properties. It has important technical significance for infrared detectors. However, due to the inherent bandgap, low carrier mobility, and dielectric constant of PbSe, it is a significant challenge to realize fast response and mid‐infrared (MID) photodetection. Chemical doping is an efficient method to regulate the band structure and carrier mobility of materials. Nevertheless, the doped film detector cannot satisfy the demands of high‐performance photodetectors. In this paper, different composition ratios powders are synthesized by a solid‐state method. The PbSe 0.5 Te 0.5 alloy film displays narrower bandgap, higher carrier mobility, excellent photo‐response, and broadband detection capacity. By utilizing the above superiority of PbSe 0.5 Te 0.5 and fast charge transfer in MoSe 2 , a PbSe 0.5 Te 0.5 /MoSe 2 p‐n heterostructure device is successfully fabricated that has significant rectifying effect (10 3 ) and extremely low dark current density (720 µA cm −2 ). The photodetector has a maximum responsivity ( R ) and specific detectivity ( D * ) of 17.5 A W −1 and 3.08 × 10 13 Jones at 780 nm. In addition, the detector displays superior photodetection performance with broadband photodetection (405–5000 nm), high switch ratios ( I on / I off = 10 5 ), and fast response speed. The above outstanding properties indicate that the PbSe 0.5 Te 0.5 /MoSe 2 heterostructure provides a promising and efficient strategy for achieving a miniaturized, broadband, and high‐performance photodetector.