First-Principles Study of the Graphene@MoSe2 Heterobilayers

Very recently, the graphene@MoSe2 heterobilayers [G@MS HBLs] were successfully synthesized experimentally. In this work, the adhesion and electronic properties of the G@MS HBLs have been studied by using density functional theory. It is found that the graphene is weakly bound to the MoSe2 monolayer without any site selectivity. The bands of G@MS HBLs have characteristic graphene-like features with a small band gap (2 meV) opening at K. However, the gap value is significantly lower than k(B)T at room temperature and can even vanish at room temperature, which suggests that the unusual electronic properties of graphene in G@MS HBLs are comparable to those in the free-standing graphene. Thus, the MoSe2 monolayer might be considered as a promising substrate for potential graphene-based devices. The physical origin of the semiconducting property is related to the inhomogeneity of the onsite energy of C atoms induced by MoSe2. Our results provide a detailed understanding of the interfacial properties of G@MS HBLs and help to predict the performance of graphene-based nanoelectronics and nanocomposites.