Integrated High-Performance Infrared Phototransistor Arrays Composed of Nonlayered PbS-MoS<sub>2</sub> Heterostructures with Edge Contacts.
basic_science · Level V
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Abstract
Molybdenum disulfide (MoS<sub>2</sub>) 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 MoS<sub>2</sub> nanostructures via van der Waals epitaxy. Density functional theory (DFT) calculations indicate that PbS nanoplates are in contact with MoS<sub>2</sub> 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 (τ<sub>rising</sub> = τ<sub>decay</sub> = 7.8 ms) as well as high photoresponsivity (4.5 × 10<sup>4</sup> A·W<sup>-1</sup>) and I<sub>light</sub>/I<sub>dark</sub> (1.3 × 10<sup>2</sup>) in the near-infrared spectral region at room temperature. In particular, the detectivity (D*) is as high as 3 × 10<sup>13</sup> 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-MoS<sub>2</sub> that are capable of infrared detection are achieved on Si/SiO<sub>2</sub> 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 MoS<sub>2</sub>-based devices in the future.