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

Highlights: • The photocurrent of monolayer WS₂-MoS₂ lateral heterojunction is investigated by using the first principle method. • CPGE is generally similar LPGE for monolayer WS2-MoS2 lateral heterojunction. • The peaks of photoresponse occur at photon energies of 2.0 eV and 2.3 eV for both LPGE and CPGE. 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.