Strain-tunable optoelectronic and photocatalytic properties of 2D GaN/MoSi2P4 heterobilayers: potential optoelectronic/photocatalytic materials

Abstract

Herein, we propose a new GaN/MoSi₂P₄ van der Waals (vdWs) heterostructure constructed by vertically stacking GaN and MoSi₂P₄ monolayers. Its electronic, optical, and photocatalytic properties are explored via DFT+G₀W₀+BSE calculations. The calculated binding energy and phonon spectrum demonstrated the material's high stabilities. The projected band structure of GaN/MoSi₂P₄ suggests that it has a desirable direct bandgap and displays type-I band alignment. It also exhibits a particularly large absorption coefficient for visible and near-infrared light while considering electron–hole interactions. Intriguingly, a small biaxial tensile strain of +1% can transform the band alignment to type-II using a direct Z-scheme mechanism for water splitting. The Z-scheme optimizes redox ability, thus perfectly engulfing the redox potentials of water and showing excellent photocatalytic activity in different layers. Our findings indicate that the GaN/MoSi₂P₄ vdWs heterostructure is a promising optoelectronic and photocatalytic material.