Effects of strategically placed water droplets on monolayer growth of molybdenum disulfide

Abstract

Two-dimensional(2D)molybdenumdisulfide(MoS 2 )filmswithatunablebandgapholdgreatpromisefornext-generationelectronic and optoelectronic devices. Synthesis of large areas of high-quality MoS 2 monolayers lacks experimental reproducibility. Moreover, the outcome of MoS 2 growth by chemical vapor deposition is dependent on several interconnected growth parameters. In this study, we present results of MoS 2 monolayer growth by strategically placing water droplets on the growth substrate and/or in the source prior to its loading in the growth chamber. The volume and distribution of water on the growth substrate and in the source had a direct impact on the morphology of the as-grown MoS 2 . Characterized by scanning electron microscopy (SEM), Raman microscopy, and atomic force microscopy (AFM), the number and size of MoS 2 layers as well as its distribution on the growth substrate were found to have a strong dependence on the positioning of the water droplet. This study on MoS 2 monolayer growth using water droplets as a promoter provides a simple and reproducible experimental technique enabling growth with high reliability.