CVD synthesis of transition metal dichalcogenides on epitaxial graphene/SiC

Full text: Van der Waals heterostructures of layered materials such as graphene, hexagonal boron nitride and transition metal dichalcogenides (TMDs) have attracted attention recently due to the ability to create synthetic materials with properties different to their constituent layers. Stacked layers of graphene and semiconducting TMDs (such as MoS₂) have previously been demonstrated to exhibit exceptional optoelectronic properties since graphene's high carrier mobility and broad spectrum absorption is complemented by high optical absorption of monolayer TMDs owing to their direct bandgap. In this work we have grown TMD layers directly on epitaxial graphene/SiC substrate by sulfurization of metal oxide precursors. We have conducted a systematic investigation of the growth parameters for MoS₂ on graphene/SiC in order to develop an understanding of the domain size, areal density and thickness of the MoS₂ domains which have been characterised by AFM, Raman spectroscopy, XPS and STM. Direct growth on TMD layers on epitaxial graphene/SiC offers controlled growth of van der Waals materials with a pristine interface on a device-ready substrate. (author)