One-Step Preparation of Large Area Films of Oriented MoS₂ Nanoparticles on Multilayer Graphene and Its Electrocatalytic Activity for Hydrogen Evolution

Superior Electrocatalytic Activity of MoS2-Graphene as Superlattice

Evidence by selected area diffraction patterns shows the successful preparation of large area (cm × cm) MoS2/graphene heterojunctions in coincidence of the MoS2 and graphene hexagons (superlattice). The electrodes of MoS2/graphene in superlattice configuration show improved catalytic activity for H2 and O2 evolution with smaller overpotential of +0.34 V for the overall water splitting when compared with analogous MoS2/graphene heterojunction with random stacking.

Probing the Growth Improvement of Large-Size High Quality Monolayer MoS₂ by APCVD

Two-dimensional transition metal dichalcogenides (TMDs) have attracted attention from researchers in recent years. Monolayer molybdenum disulfide (MoS₂) is the direct band gap two-dimensional crystal with excellent physical and electrical properties. Monolayer MoS₂ can effectively compensate for the lack of band gap of graphene in the field of nano-electronic devices, which is widely used in catalysis, transistors, optoelectronic devices, and integrated circuits. Therefore, it is critical to obtain high-quality, large size monolayer MoS₂. The large-area uniform high-quality monolayer MoS₂ is successfully grown on an SiO₂/Si substrate with oxygen plasma treatment and graphene quantum dot solution by atmospheric pressure chemical vapor deposition (APCVD) in this paper. In addition, the effects of substrate processing conditions, such as oxygen plasma treatment time, power, and dosage of graphene quantum dot solution on growth quality and the area of the monolayer of MoS₂, are studied systematically, which would contribute to the preparation of large-area high-quality monolayer MoS₂. Analysis and characterization of monolayer MoS₂ are carried out by Optical Microscopy, AFM, XPS, Raman, and Photoluminescence Spectroscopy. The results show that monolayer MoS₂ is a large-area, uniform, and triangular with a side length of 200 μm, and it is very effective to treat the SiO₂/Si substrate by oxygen plasma and graphene quantum dot solution, which would help the fabrication of optoelectronic devices.