Interfacial interaction in monolayer transition metal dichalcogenides (MX2)/metal oxide heterostructures and its effects on electronic and optical properties: The case of MX2/CeO2

Two-dimensional transition metal dichalcogenides (MX2)/metal oxide heterostructures have shown unique physical properties, making them promising materials for various applications ranging from photocatalysis to solar energy conversion. Understanding the interfacial interactions is highly desirable for designing these heterostructures having excellent performance. Here we systematically study the interfacial interaction in monolayer MX2 (M=Mo, W; X=S, Se)/CeO2 heterostructures and its effects on electronic and optical properties by density functional theory. It is found that the interfacial interaction in the MX2/CeO2 depends predominantly on the chalcogen (X) element. Particularly, the band gap variation and important electronic states at conduction band minimum or valence band maximum of the heterostructures are determined by the strength of interfacial interaction. The MX2/CeO2 heterostructures with the same chalcogen (X) element have similar absorption spectra from ultraviolet to near-infrared regions. These results suggest that the chalcogen (X) element is a key factor in tuning the properties of MX2/metal oxide heterostructures.