Synthesis of Centimeter-Sized Continuous Monolayer Tungsten Disulfide Films Using the Expansion Growth Space Atmospheric Pressure Chemical Vapor Deposition Method

Monolayer tungsten disulfide (WS2) exhibits stable physical properties and remarkable photoelectric characteristics, rendering it a highly favored choice for the fabrication of photoelectric devices. However, the preparation of large-area monolayer WS2 remains challenging. In this study, we propose an atmospheric pressure chemical vapor deposition (APCVD) method to grow large-area monolayer WS2 films. By increasing the chamber space, we achieved a slow and even discharge of air flow during atmospheric growth, resulting in a relatively uniform concentration in the reaction zone. The large-area monolayer WS2 films (∼cm) can be obtained by regulating the growth temperature and gas flow rate. We reduce the evaporation temperature of WO3 by adding KI. Different concentrations of hydrogen (H2) were used for comparison: too low rate would led to grow a small sample due to insufficient catalysis; however, too high rate caused H2 etching on the sample surface. Finally, we prepared monolayer WS2 films by controlling the temperature and flow rate of the carrier gas. Our APCVD equipment and method are simple, efficient, and inexpensive.