A systematic study of the synthesis of monolayer tungsten diselenide films on gold foil

We report a systematic study of the synthesis of large-area monolayer WSe 2 on gold foil by controlling the growth temperature and the partial pressure of hydrogen during chemical vapor deposition. The gold surface causes surface-mediated growth to form monolayer WSe 2 films. The amount of the tungsten source is controlled by adjusting the partial pressure of hydrogen, which plays a role in the reduction of WO 3 (solid phase) into WO 3−x (vapor phase). The coverage of monolayer WSe 2 can be effectively controlled by changing either the partial pressure of hydrogen or the growth temperature at a fixed growth time under an Se-rich atmosphere, resulting in 100% coverage of the WSe 2 film. The crystallinity and thickness uniformity are characterized by Raman spectroscopy, photoluminescence, and transmission electron microscopy. This characterization reveals that the quality of the WSe 2 film is comparable to mechanically-exfoliated monolayer WSe 2 and possesses good thickness uniformity.