Tunable Electronic and Optical Properties of a Planar Hydrogenated AsSi Hybrid Nanosheet: A Potential Wide Water-Splitting Photocatalyst

Two-dimensional (2D) layered structures have recently drawn worldwide attention in material science and device physics because of their intriguing electrical and optical properties. In this paper, the structural, electronic, and magnetic properties of fully and partially hydrogenated AsSi nanosheets (NSs) are investigated by first-principles calculations based on density functional theory. Moreover, the potential as photocatalysts for water splitting is also studied. The results demonstrate that hydrogenated H atoms have a great influence on the electronic properties of the AsSi NS. By decorating their surface, fully and semihydrogenated AsSi NSs still exhibit ferromagnetism states and are predicated to be metallic or semiconductive depending on the surface coverage. Calculation results show that a more stable configuration of the semihydrogenated AsSi NS (AsSiH) is the one wherein all H atoms are adsorbed onto Si atoms, which is a semiconductor as the applied biaxial strains are from -6 to 9% and the band gap reaches its maximum with 4% tensile strain. More remarkably, AsSiH NSs with tensile strains up to 9% exhibit proper band gaps, valence, and conduction band positions of the reduction and oxidation levels in visible-light-driven water splitting. The diverse electronic and optical properties highlight hydrogenated AsSi NSs' potential applications in efficient electronic and optoelectronic devices.