Photoelectric properties of monolayer WS2-MoS2 lateral heterojunction from first principles

Abstract

The first-principles calculation is applied to investigate the photocurrents elicited by the circular photogalvanic effect (CPGE) and linear photogalvanic effect (LPGE) of monolayer WS2-MoS2 lateral heterojunction. Our results demonstrate that the band alignment of the WS2-MoS2 lateral heterojunction belongs to type-II, which can effectually isolate electron-hole pairs and augment the photocurrent conversion rate of the heterojunction. Furthermore, the photocurrent generated by LPGE and CPGE both have peaks around the photon energy of 2.0 eV and 2.3 eV, which can be subject to explain by DOS via Fermi's Golden Rule. More importantly, the monolayer WS2-MoS2 lateral heterojunction exhibits an obvious photocurrent effect, which also attest the existence of the PN junction. These results will contribute some theoretical guidance for the application of the WS2-MoS2 lateral heterojunction in the area of optoelectronics.