Large-Area Buckled MoS₂ Films on the Graphene Substrate

In this study, a novel buckled structure of edge-oriented MoS₂ films is fabricated for the first time by employing monolayer graphene as the substrate for MoS₂ film growth. Compared to typical buckling methods, our technique has several advantages: (1) external forces such as heat and mechanical strain are not applied; (2) uniform and controllable buckling over a large area is possible; and (3) films are able to be transferred to a desired substrate. Dual MoS₂ orientation was observed in the buckled film where horizontally aligned MoS₂ layers of 7 nm thickness were present near the bottom graphene surface and vertically aligned layers dominated the film toward the outer surface, in which the alignment structure was uniform across the entire film. The catalytic ability of the buckled MoS₂ films, measured by performing water-splitting tests in acidic environments, shows a reduced onset potential of -0.2 V versus reversible hydrogen electrode (RHE) compared to -0.32 V versus RHE for pristine MoS₂, indicating that the rough surface provided a higher catalytic activity. Our work presents a new method to generate a buckled MoS₂ structure, which may be extended to the formation of buckled structures in various 2D materials for future applications.