Electronic structure, optical and photocatalytic characteristics of van der Waals Al2SeTe/WSeTe heterostructure

Abstract

The escalating global energy crisis and environmental pollution highlight the urgent need for sustainable energy conversion technologies. Photocatalysis, inspired by natural photosynthesis, provides a promising route for solar-to-hydrogen production. Two-dimensional van der Waals (vdW) heterostructures, integrating monolayer semiconductors, offer enhanced photocatalytic efficiency through improved charge separation and tunable interfacial interactions. Using density functional theory, this study investigates the electronic, optical, and photocatalytic properties of Al₂SeTe, WSeTe monolayers, and their vdW heterostructure. Fermi-level alignment induces an internal electric field that facilitates efficient charge transfer while suppressing carrier recombination. The WSeTe/Al₂SeTe heterostructure exhibits thermodynamic stability and a type-I band alignment with an indirect band gap of 0.557 eV, suitable for overall water splitting at neutral pH. Moreover, biaxial strain effectively modulates its optoelectronic characteristics, offering tunability for energy applications. These results provide valuable insights into designing high-performance heterostructures for photocatalytic hydrogen generation.