Monolayered H-Si-P semiconductors: structural stability, electronic structure, optical properties, and prospects for photocatalytic water splitting.

Abstract

Group IV and V monolayers are promising state-of-the-art two-dimensional (2D) materials owing to their high carrier mobility, tunable bandgaps, and optical linear dichroism along with outstanding electronic and thermoelectric properties. Furthermore, recent studies revealed the stability of free-standing 2D monolayers by hydrogenation. Inspired by this, we systematically predicted and investigated the structure and properties of various hydrogen-saturated silicon phosphide (H-Si-P) monolayers based on first-principles calculations. According to the results, H-Si-P monolayers belong to indirect bandgap semiconductors with a highly stable structure. Their bandgaps and band edge positions assessed using accurate hybrid functional are shown to be effectively adjusted by applying a biaxial strain. Furthermore, the absorption spectra of these monolayers, simulated in the context of time-dependent density functional theory, exhibit their excellent potential for solar energy conversion and visible-light-driven photocatalytic water splitting. In this respect, this work provides valuable guidance for finding more 2D semiconductors and nanostructures for nanoelectronics and optoelectronic applications, as well as for photocatalytic water splitting.