2D-polyimide film sensitized monolayer MoS₂ phototransistor enabled near-infrared photodetection

Two-dimensional (2D) transition metal dichalcogenides (TMDCs)-based heterostructures open the door to fabricate various promising hybrid photodetectors, while it is still a challenge to achieve excellent and stable near-infrared (NIR) photoresponse. Here, a MoS₂–2DPI (2D-polyimide (2DPI)) heterojunction-based phototransistor (HPT) was fabricated. Near-infrared photodetection with excellent performance has been realized. This HPT exhibited a photoresponsivity of 390.5 A/W, a specific detectivity of 5.10 × 10¹² Jones, a photogain 1.04 × 10⁵, and a photoresponse rise and decay time of 400 and 430 ms (λ = 900 nm, P = 16.2 μW/cm²), respectively. It also shows a broadband wavelength response from 405 to 1,020 nm. This superior performance could be attributed to the strong near-infrared absorption and the type-II (staggered) band alignment which ensures efficient charge transfer from 2DPI to MoS₂. The face-to-face spatial configuration of MoS₂–2DPI heterostructures ensures efficient transfer of photoinduced carriers through the interface, electron and holes can be separated due to the large band offsets. This work presents a significant step for the manipulation of high-performance NIR photodetector of two-dimensional covalent organic polymer-sensitized monolayer TMDCs.