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

Abstract

Abstract Molybdenum disulfide (MoS2) is two-dimensional transition metal dichalcogenides that has garnered significant interest as a potential alternative to graphene. The synthesis of large-area monolayer MoS2 via CVD is highly anticipated. To investigate the growth-promoting effect of sodium, NaCl and Na2SO4 were used as additives for CVD synthesis, as they have a similar mp to the commonly used MoO3 precursor. The increase in the domain size of monolayer MoS2 with using Na compounds was confirmed through X-ray photoelectron spectroscopy analysis. The results suggested that the growth of MoS2 may have been promoted by the reaction of Na with S. Moreover, it was found that monolayer MoS2 with improved crystallinity and larger domain size could be synthesized using Na2SO4 as an additive compared to NaCl.