LAUSR

An infrared detector with high responsivity based on graphene–PbSe thin film heterojunction was reported. High-quality PbSe thin film and graphene were prepared by molecular beam epitaxy and chemical vapor deposition, respectively. The physical characteristics of PbSe thin film and graphene were performed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman measurement. The phototransistor using PbSe thin film as a sensitizer and graphene as a channel to transport excitons exhibits peak responsivity and detectivity up to ~ 420 A·W −1 and 5.9 × 10 11  Jones (radiation intensity: 0.75 mW·cm −2 ) at room temperature in the near-infrared (NIR) region, respectively. The high optical response is attributed to the photo-excited holes transferring from PbSe film to graphene under irradiation. Moreover, it is revealed that the responsivity of graphene–PbSe phototransistor is gate-tunable which is important in photodetectors.