Applied Surface Science, Vol.470, 129-134, 2019
Low-temperature wafer-scale growth of MoS2-graphene heterostructures
In this study, we successfully demonstrate the fabrication of a MoS2-graphene heterostructure (MGH) on a 4 inch wafer at 300 degrees C by depositing a thin Mo film seed layer on graphene followed by sulfurization using H2S plasma. By utilizing Raman spectroscopy and high-resolution transmission electron microscopy, we have confirmed that 5-6 MoS2 layers with a large density of sulfur vacancies are grown uniformly on the entire substrate. The chemical composition of MoS2 on graphene was evaluated by X-ray photoelectron spectroscopy, which confirmed the atomic ratio of Mo to S to be 1:1.78, which is much lower than the stoichiometric value of 2 from standard MoS2. To exploit the properties of the nanocrystalline and defective MGH film obtained in our process, we have utilized it as a catalyst for hydrodesulfurization and as an electrocatalyst for the hydrogen evolution reaction. Compared to MoS2 grown on an amorphous SiO2 substrate, the MGH has smaller onset potential and Tafel slope, indicating its enhanced catalytic performance. Our practical growth approach can be applied to other two-dimensional crystals, which are potentially used in a wide range of applications such as electronic devices and catalysis.