First-Principles Investigation of Type-II GaO-MX 2 (M= Mo, W; X= S, Se) van der Waals Heterostructures for Enhanced Optoelectronic, Photocatalytic and Energy Conversion Applications

Abstract

Two-dimensional (2D) van der Waals heterostructures (vdWHs) offer an effective strategy to enhanced the electronic, optical and photocatalytic properties of 2D materials. In this paper, first-principles calculations were used to calculate the structural stability, electronic properties, interfacial charge transfer, optical response and photocatalytic performance of GaO-MX 2 (M = Mo, W; X = S, Se) vdWHs. Six stacking configurations were investigated for each vdWHs, and their energetic and thermal stability were confirmed by binding energy, interlayer spacing and ab initio molecular dynamics simulations. GaO-MX 2 vdWHs showing indirect type-II band alignment, facilitating efficient charge separation and reducing electron and hole recombination.Charge density difference, work function and electrostatic potential confirmed significant interfacial charge redistribution and built-in electric fields. Furthermore, GaO-MX 2 vdWHs demonstrate strong visible-to-near-infrared light absorption with enhanced solar-harvesting capability. Photocatalytic water splitting indicates that GaO-MoS 2 and GaO-WS 2 satisfy the band-edge requirements for visible-light-driven water splitting, highlighting their potential for photocatalytic and optoelectronic applications.