Syntheses and bandgap alterations of MoS 2 induced by stresses in graphene-platinum substrates

Abstract Epitaxially-oriented large-scale monolayer molybdenum disulfide (MoS 2 ) grown directly on graphene (Gr) with an atomic-clean interface draws intensive interest in both areas of fundamental sciences and electronic-device applications. In general, however, synthetic characteristics and bandgap-related properties of MoS 2 crystals can be varied by the selection of substrates that support Gr, and mechanisms that govern these phenomena remain unclear. Here, by means of scanning tunneling microscope and spectroscopy (STM/STS) and photoluminescence (PL) measurements, we have discovered that considerably-strained Gr can strongly affect the epitaxy of MoS 2 crystals and enhance the interlayer electronic coupling between monolayer MoS 2 and its Gr-platinum (Pt) substrate, leading to the stack of MoS 2 layers and a narrowing direct bandgap of monolayer MoS 2 . Our studies shed light on growing large-scale MoS 2 films on Gr and the bandgap modulation in these heterostructures.