Large-area, high-quality two-dimensional molybdenum disulfide crystals have commonly been grown through powder vaporization because of its simplicity and cost-effectiveness. However, the sulfurization process for molybdenum trioxide, through interactions with sulfur, still remains poorly understood and insufficiently investigated. Ab initio calculations and molecular dynamics simulations of the reaction of sulfur allotropes (S2-8) with molybdenum trioxide and experimentally proposed molybdenum oxysulfide intermediates (MoO2S, MoOS2) have been used to elucidate the mechanistic steps in the sulfurization pathway. These simulations show that the sulfurization process takes place through the formation of molybdenum oxysulfide rings, which can decompose into more sulfurized molybdenum species, oxysulfur molecules and/or smaller sulfur allotropes. Based on our analysis, we have identified a potentially unique role for S3 in the direct sulfurization of molybdenum trioxide by sulfur vapor. As the sulfur allotrope distribution in sulfur vapor is temperature dependent, our results not only provide critical mechanistic insight into the sulfurization process, but also identify how experimental growth parameters can be adjusted to maximize the efficiency of the powder vaporization process.

Role of molybdenum oxysulfide rings in the growth of MoS2 from sulfurization of MoO3

256th National Meeting (2018)

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