Tunable photocatalytic and optoelectronic properties of SiTe/SiH heterostructure as a photocatalytic water splitting with high hydrogen production

The development of appropriate photocatalysts based on semiconductors is crucial for overcoming energy and environmental challenges. Especially, photocatalysts of water splitting are attractive nanomaterials. In the present work, a new β-SiTe/SiH van der Waals heterostructure has been produced by stacking the SiTe monolayer on top of the SiH monolayer. The electronic band structure, optical characteristics, photocatalytic capabilities and stability of the SiTe/SiH heterostructure were comprehensively examined based on the density functional theory. The obtained results indicated that biaxial strain is an effective strategy for improving the properties under consideration. These results demonstrated that the stable SiTe/SiH heterostructure exhibits a type II band alignment and possesses an indirect band gap of 1.725 eV/2.307 eV according to the PBE/HSE06 method. When the biaxial strain increases, the band gap of SiTe/SiH decreases linearly, reaching a minimum band gap when subjected to a strain of −6 %. Moreover, the SiTe/SiH heterostructure reveals an upward trend in optical properties within the visible spectrum, peaking in the visible and violet regions. Furthermore, the photocatalytic characteristics conserved at strains from −4% to +6 % because the band edges satisfy the reduction and oxidation standard potentials. A biaxial strain influence may be used to regulate the SiTe/SiH heterostructure, which smoothly enhances photogenerated carrier segregation. Consequently, the heterostructure is a perfect choice for photovoltaic application and photocatalysis due to its high optical absorption, and adjustable photocatalytic and electronic properties. [Display omitted] •The SiTe/SiH heterostructure is structurally, dynamically, and thermally stable.•The SiTe/SiH heterostructure exhibits a type II band alignment with an indirect bandgap of 1.725 (PBE)/2.307 (HSE06) eV.•SiTe/SiH vdW heterostructure is a robust candidate for the production of photocatalytic hydrogen.•A significant transformation occurs in the bandgap of the SiTe/SiH heterostructure, from indirect to direct at strain of 6 %.