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 nanocrystalson a substrate could be considerably useful in electrochemical applicationsbecause of the high density of edge states. In this study, layeredMoS(2) nanocrystals less than 50 nm in diameter were synthesizedby overlapping with each other as vertical growth in the form of afilm with an area of 10 mm x 40 mu m using metal-organicchemical vapor deposition (MOCVD) for the lateral growth of TMDs.Notably, in the spatial distribution, a singular point where the verticalgrowth is promoted was found through optical dark-field data and spatiallyresolved micro-Raman spectroscopy. The accelerated vertical growthregion distinguished by the singular point is due to the layer-dependentdielectric constant of MoS2, which affects the surfaceenergy and changes the conditions of vapor-phase deposition. In addition,with these phenomena, we discuss a way for expanding the hierarchicalvertically grown MoS2 region on a substrate through analyticalmethods based on hydromechanics.