Lateral Graphene-Contacted Vertically Stacked WS<sub>2</sub> /MoS<sub>2</sub> Hybrid Photodetectors with Large Gain.
basic_science · Level V
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- Record sourced from PubMed, PMID 29044833.
- Also identified by DOI 10.1002/adma.201702917.
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Abstract
A demonstration is presented of how significant improvements in all-2D photodetectors can be achieved by exploiting the type-II band alignment of vertically stacked WS<sub>2</sub> /MoS<sub>2</sub> semiconducting heterobilayers and finite density of states of graphene electrodes. The photoresponsivity of WS<sub>2</sub> /MoS<sub>2</sub> heterobilayer devices is increased by more than an order of magnitude compared to homobilayer devices and two orders of magnitude compared to monolayer devices of WS<sub>2</sub> and MoS<sub>2</sub> , reaching 10<sup>3</sup> A W<sup>-1</sup> under an illumination power density of 1.7 × 10<sup>2</sup> mW cm<sup>-2</sup> . The massive improvement in performance is due to the strong Coulomb interaction between WS<sub>2</sub> and MoS<sub>2</sub> layers. The efficient charge transfer at the WS<sub>2</sub> /MoS<sub>2</sub> heterointerface and long trapping time of photogenerated charges contribute to the observed large photoconductive gain of ≈3 × 10<sup>4</sup> . Laterally spaced graphene electrodes with vertically stacked 2D van der Waals heterostructures are employed for making high-performing ultrathin photodetectors.