Lateral multilayer/monolayer MoS₂ heterojunction for high performance photodetector applications

Inspired by the unique, thickness-dependent energy band structure of 2D materials, we study the electronic and optical properties of the photodetector based on the as-exfoliated lateral multilayer/monolayer MoS₂ heterojunction. Good gate-tunable current-rectifying characteristics are observed with a rectification ratio of 10³ at V _gs = 10 V, which may offer an evidence on the existence of the heterojunction. Upon illumination from ultraviolet to visible light, the multilayer/monolayer MoS₂ heterojunction shows outstanding photodetective performance, with a photoresponsivity of 10³ A/W, a photosensitivity of 1.7 × 10⁵ and a detectivity of 7 × 10¹⁰ Jones at 470 nm light illumination. Abnormal photoresponse under positive gate voltage is observed and analyzed, which indicates the important role of the heterojunction in the photocurrent generation process. We believe that these results contribute to a better understanding on the fundamental physics of band alignment for multilayer/monolayer MoS₂ heterojunction and provide us a feasible solution for novel electronic and optoelectronic devices.