Strong interfacial interaction and enhanced optical absorption in graphene/InAs and MoS2/InAs heterostructures

Abstract

Vertical heterostructures of two-dimensional materials have recently emerged as a promising application in designing novel electronic and optoelectronic devices. By using first principles methods, we investigated the electronic and optical properties of two heterostructures, graphene/InAs and MoS₂/InAs. The results reveal that the interfacial structure, coupling, and transfer charges are crucial to enhance the electronic properties and optical adsorption of heterostructures. We found obvious electron–hole pair separation and an in-built polarized electric field at the interface in graphene/InAs heterostructures. In particular, the strong interface electronic coupling opens a 15 meV band gap in graphene after the adsorption on an InAs slab substrate. Benefiting from the interfacial coupling and transfer charge, the optical properties of graphene/InAs heterostructures are slightly enhanced compared to those of isolated composites of heterostructures. Remarkably, MoS₂/InAs heterostructures were found to have a larger redistribution of charge, a smaller interlayer distance, and a stronger interfacial interaction than graphene/InAs heterostructures. The calculated optical absorption of MoS₂/InAs heterostructures shows more significant absorption properties in the visible region than that of graphene/InAs heterostructures. The mechanisms to understand these phenomena are suggested.