Large-Area Synthesis of Continuous and Uniform MoS2 Monolayer Films on Graphene

Heterostructures composed of multiple layers of different atomically thin materials are of interest due to their unique properties and potential for new device functionality. MoS2-graphene heterostructures have shown promise as photodetectors and vertical tunnel transistors. However, progress is limited by the typically micrometer-scale devices and by the multiple alignments required for fabrication when utilizing mechanically exfoliated material. Here, the synthesis of large-area, continuous, and uniform MoS2 monolayers directly on graphene by chemical vapor deposition is reported, resulting in heterostructure samples on the centimeter scale with the possibility for even larger lateral dimensions. Atomic force microscopy, photoluminescence, X-ray photoelectron, and Raman spectroscopies demonstrate uniform single-layer growth of stoichiometric MoS2. The ability to reproducibly generate large-area heterostructures is highly advantageous for both fundamental investigations and technological applications.