Interlayer coupling of a direct van der Waals epitaxial MoS2/graphene heterostructure

Abstract

Many efforts have been undertaken towards the synthesis of vertically stacked two-dimensional (2D) crystals due to their unique electronic and optical properties. Here, we present direct molecular beam epitaxy (MBE) growth of a MoS₂/graphene heterostructure by a strict epitaxial mechanism. By combining Raman, photoluminescence, transmission electron microscopy characterizations and first-principles calculations, we find that there exists a strain effect and strong interlayer coupling between MoS₂ and graphene resulting from the intrinsic crystal lattice mismatch, which could generate potential metallic behavior of the heterostructure. The direct epitaxial technique applied here enables us to investigate the growth mechanisms and interlaminar interaction of 2D heterostructures without sample handling and transfer, and offers a new approach to synthesize multilayer electronic and photonic devices.