Photoresponsivity-Enhanced PbS Quantum Dots/Graphene/Silicon Near-Infrared Photodetectors

The high carrier mobility in graphene, together with the ease of handling and good optical properties of colloidal quantum dots, provide high-performance materials for next-generation photodetectors. In this paper, we investigated PbS quantum dots/graphene/Si near-infrared (NIR) photodetectors. The absorption of infrared light was increased by inserting a layer of Al2O3 between graphene and Si to reduce the tunneling of carriers, and spin-coating PbS quantum dots on graphene to form a thin film by liquid phase exchange to replace ligands, thereby improving the device performance of PbS quantum dots/graphene/Si NIR photodetectors. Under the incident 1550 nm light, the responsivity of the detector is 0.16 A/W. Our work contributes to the study of related near-infrared silicon-based photodetectors.