MOCVD Growth of Hierarchical Nanostructured MoS2: Implications for Reactive States as the Large-Area Film

Abstract

Large-area hierarchical grown transition metal dichalcogenide (TMD) nanostructures as out-of-plane directional layered TMD nanocrystals on a substrate could be considerably useful in electrochemical applications because of the high density of edge states. In this study, layered MoS2 nanocrystals less than 50 nm in diameter were synthesized by overlapping with each other as vertical growth in the form of a film with an area of 10 mm × 40 μm using metal–organic chemical vapor deposition (MOCVD) for the lateral growth of TMDs. Notably, in the spatial distribution, a singular point where the vertical growth is promoted was found through optical dark-field data and spatially resolved micro-Raman spectroscopy. The accelerated vertical growth region distinguished by the singular point is due to the layer-dependent dielectric constant of MoS2, which affects the surface energy and changes the conditions of vapor-phase deposition. In addition, with these phenomena, we discuss a way for expanding the hierarchical vertically grown MoS2 region on a substrate through analytical methods based on hydromechanics.