Synthesis of MoS2 ribbons and their branched structures by chemical vapor deposition in sulfur-enriched environment

Here, we demonstrate the synthesis of monolayer molybdenum disulfide (MoS2) ribbons and their branched structures by chemical vapor deposition (CVD) in sulfur-enriched environment. The growth of the MoS2 ribbons, triangular and other crystals significantly depends on the exposure of sulfur and concentration of molybdenum oxide (MoO3) vapor on the substrate surface. The width and length of the synthesized ribbons is around 5-10 and 50-100 mu m, respectively, where the width reduces from the nucleation point toward the end of the ribbon. Unidirectional, bi and tri-directional growth of ribbons from the nucleation point with an angle of 60 and 120 were obtained attributing to crystallographic growth orientation of MoS2 crystals. The directional growth of dichalcogenides ribbons is a significant challenge, our process shows that such unidirectional and other branched structures can be achieved by controlling the stoichiometric composition of MoO3 and sulfur exposure on the substrate surface. Interestingly, all the individual and branched ribbons possess uneven abundant edge structures, where the edges are formed with angles of 60 and 120, indicating variation in molybdenum and sulfur edge terminations. The directional growth of MoS2 ribbons with defined edge structures in particular CVD condition can open up new possibilities for electronic and electrochemical applications. (C) 2017 Elsevier B.V. All rights reserved.