Unveiling the CVD growth mechanism of MoS ₂ : exploring precursors, promoters, and evolution of reaction pathways

Abstract Transition metal dichalcogenides (TMDCs) have garnered significant attention as promising next-generation semiconductor materials due to their unique physical properties at the atomic scale. However, current synthesis techniques face challenges in achieving large-area uniformity and compatibility with integrated circuit processes, limiting their practical adoption in industry. In this study, we conduct a comprehensive investigation into the decomposition and phase evolution of the molybdenum precursor, MoO 3 , during MoS 2 synthesis using H 2 S as the sulfur source. Our approach introduces water vapor (H 2 O) as a promoter, which plays a crucial role in enhancing the growth efficiency and crystallinity of MoS 2 . Through systematic characterizations, including Raman spectroscopy, photoluminescence, atomic force microscopy, and x-ray diffraction, we demonstrate that the introduction of water vapor significantly improves MoS 2 growth by suppressing excessive reduction of MoO 3 and forming volatile Mo 2 (OH) 2 intermediates. This promotes large-area, high-crystallinity MoS 2 growth under milder conditions. These findings provide a promising strategy for the scalable and high-quality synthesis of TMDCs, paving the way for their integration into high-performance electronic devices.