Effect of Processing Parameters on Monolayer MoS2 Prepared by APCVD in a Quasiclosed Crucible

Chemical vapor deposition is one of the universally acknowledged methods to synthesize two-dimensional transition-metal dichalcogenides with high crystal quality and large size. However, variations in the process parameters directly influence the number of layers and the quality of molybdenum disulfide (MoS 2 ) films. Thus, achieving controllable growth of monolayer MoS 2 films is still a challenge. In this study, the immunity of the monolayer nature of MoS 2 domains to process parameters was systematically investigated by varying the vaporization/growth temperature, time of sulfur addition, ramp rate, and distance between the precursors and receiving substrate using a quasiclosed crucible in a modified atmospheric-pressure CVD system. The results indicated that incorporating a quasiclosed crucible could facilitate controllable growth of monolayer MoS 2 films where the monolayer nature is immune to process parameters. Further, we attempted to elucidate the growth mechanism of monolayer MoS 2 films, which will contribute toward precise control over the synthesis of MoS 2 and other transition-metal dichalcogenides within a broad processing window.