CVD synthesis of monolayer MoS2 using Na compounds as additives to enhance two-dimensional growth

Abstract Molybdenum disulfide (MoS 2 ) is two-dimensional transition metal dichalcogenides that has garnered significant interest as a potential alternative to graphene. The synthesis of large-area monolayer MoS 2 via CVD is highly anticipated. To investigate the growth-promoting effect of sodium, NaCl and Na 2 SO 4 were used as additives for CVD synthesis, as they have a similar mp to the commonly used MoO 3 precursor. The increase in the domain size of monolayer MoS 2 with using Na compounds was confirmed through X-ray photoelectron spectroscopy analysis. The results suggested that the growth of MoS 2 may have been promoted by the reaction of Na with S. Moreover, it was found that monolayer MoS 2 with improved crystallinity and larger domain size could be synthesized using Na 2 SO 4 as an additive compared to NaCl.