Transition of the electronic structure in the BAs/CrS2 van der Waals heterostructure

A novel BAs/CrS2 van der Waals heterostructure is manufactured and the stability, electronic and optical properties of the heterostructure under biaxial strain are researched. The formation of the heterostructure makes CrS2, which is originally a conductor, shows the properties of semiconductor. The BAs/CrS2 heterostructure with a small band gap of 0.24 eV has typical type-II heterostructure characteristics. Under the action of the built-in election field (Eint), the heterostructure manifests a Z-scheme peculiarity which can help it participate into water splitting reaction. Under biaxial strains, the binding energy of the heterostructure shows an increasing trend with the increase of strain, and the band structure changes obviously with biaxial strain especially around Fermi level. The heterostructure will transform from type-II to type-I and even transform to metal under biaxial strain regulation. The absorption peak of the heterostructure moves in succession to the short wave region as the magnitude of the compressive strain increases, while under tensile strain, the absorption peak of the heterostructure moves to the long wave region in succession as the magnitude of the tensile strain increases. Our results provide an essential guidance for tuning the electronic properties of the heterostructure through the powerful means of the strain engineering, which has great significance for practical optoelectronic device applications.