First-principles calculations to investigate the electronic and optical properties of (MoS2)4-n/(MoSSe)n lateral heterostructure

Abstract

The electronic properties, work function, and optical properties of the lateral heterostructure formed after combining MoS2 and Janus MoSSe ((MoS2)4-n/(MoSSe)n, where n is the width of Janus MoSSe) have been investigated comparatively using first-principles calculations. The electronic structure analysis shows that the band gaps decrease from 1.69 eV for (MoS2)4/(MoSSe)0–1.41 eV for (MoS2)0/(MoSSe)4. Based on the calculated density of states calculations, the valence band edge (VBE) is mainly contributed by Mo 4d states, while the conduction band edge (CBE) is originated from the contribution of Mo 4d and Se 4p orbital hybridization. As the width n increases, the average positive charge on Mo atoms decreases, while the average charge on Se increases. As a consequence, there is a significant enhancement of the built-in electric field in the z-direction, inducing the work functions changed from 6.17 eV for (MoS2)4/(MoSSe)0–5.22 eV for (MoS2)0/(MoSSe)4. The results of this study imply that forming (MoS2)4-n/(MoSSe)n lateral heterostructure systems which can have adjustable work function and built-in electric field, bring new properties and great potential in different applications.