The electronic structures and optical properties of light-element atom adsorbed SnSe monolayers

Abstract

The effect of adsorption of different light-element atoms on the electronic structures and optical properties of single-layered SnSe sheets are investigated using density-functional theory. The optimized structures of SnSe monolayers with the adatoms (H, Li, B, C, N, O and F) are calculated by full optimization method. We found that depending on the nature of the adatoms, SnSe monolayers can be designed to be either metal or semiconductor. With the decoration of H, Li, B, N or F adatoms, SnSe monolayers become metallic, either resulted from the formation of impurity bands (H, B and N) or the shifts of energy bands (Li and F). With the decoration of C or O adatoms, SnSe monolayers remain semiconducting, but the band structures change evidently, resulting in robust modulation of effective masses of charge carriers near band edges and optical absorption properties of the monolayers. Our calculated results demonstrate that the electronic and optical properties of SnSe monolayers can be tuned by adsorption of light-element adatoms which may be used in electrical and optical applications.