Integrated High-Performance Infrared Phototransistor Arrays Composed of Nonlayered PbS-MoS2 Heterostructures with Edge Contacts

Molybdenum disulfide (MoS2) has attracted a great deal of attention in optoelectronic applications due to its high mobility, low off-state current and high on/off ratio. However, its intrinsic large bandgap limits its application in infrared detection. Here, we have developed a high-performance infrared photodetector by integrating nonlayered PbS and layered MoS2 nanostructures via van der Waals epitaxy. Density functional theory (DFT) calculations indicate that PbS nanoplates are in contact with MoS2 edges through strong chemical hybridization, which is expected to offer a fast transmission path for carriers that enhances the response speed. The phototransistor exhibits a fast response (τrising = τdecay = 7.8 ms) as well as high photoresponsivity (4.5 × 104 A·W-1) and Ilight/Idark (1.3 × 102) in the near-infrared spectral region at room temperature. In particular, the detectivity (D∗) is as high as 3 × 1013 Jones, which is even better than that of commercial Si and InGaAs photodetectors. Furthermore, by controlling the growth and microfabrication patterning, periodic device arrays of PbS-MoS2 that are capable of infrared detection are achieved on Si/SiO2 substrates. Our work provides a possible method for the integration of photodetector arrays on Si-based electronic devices and lays a solid foundation for the practical applications of MoS2-based devices in the future.