Catalytic chemical vapor deposition of large-area uniform two-dimensional molybdenum disulfide using sodium chloride

The effective synthesis of atomically thin molybdenum disulfides (MoS₂) of high quality and uniformity over a large area is essential for their use in electronic and optical devices. In this work, we synthesize MoS₂ that exhibit a high quality and large area uniformity using chemical vapor deposition (CVD) with volatile S organic compound and NaCl catalysts. In the latter process, the NaCl enhances the growth rate (5 min for synthesis of monolayer MoS₂) and purity of the synthesized MoS₂. The optical microscopy, Raman spectroscopy, x-ray photoemission spectroscopy, photoluminescence, and transmission electron microscopy measurements indicate that the NaCl-CVD MoS₂ has a large grain size, clear Raman shift, strong photoluminescence, good stoichiometry, and 6-fold coordination symmetry. Moreover, we demonstrate that the electron mobility (10.4 cm² V^-1 s^-1) and on/off current ratio (3 ×10⁷) of monolayer MoS₂ measured using a field-effect transistor are comparable to those of previously reported MoS₂ synthesized using CVD.