A self-powered high-performance photodetector based on a MoS2/GaAs heterojunction with high polarization sensitivity

Abstract

The rich variety and unique optoelectrical properties of two-dimensional (2D) layered nanomaterials allow researchers to design various photodetectors working at different wavelengths. In this study, a self-powered broadband photodetector was fabricated by constructing a heterojunction from a 2D MoS₂ film and bulk GaAs. The MoS₂/GaAs heterojunction photodetector demonstrated a wide response spectrum from deep ultraviolet (DUV) to near-infrared (NIR) with a high responsivity of 35.2 mA W⁻¹, a high specific detectivity of 1.96 × 10¹³ Jones and a fast response speed of 3.4/15.6 μs at zero bias. Further investigation reveals that the MoS₂/GaAs heterojunction photodetector shows high polarization sensitivity to a polarized optical signal with a peak-to-valley ratio of 4.8. Such high-performance and high polarization sensitivity of the MoS₂/GaAs heterojunction photodetector indicate that it has great potential for photodetection in a complex environment.