The usage of molten salts, for example, Na2MoO4and Na2WO4, has shown great success in the growth of two-dimensional (2D) transition metal dichalcogenides (TMDCs) by chemical vapor deposition (CVD). In comparison with the halide salt (i.e., NaCl, NaBr, and KI)-assisted growth (Salt 1.0), the molten salt-assisted vapor-liquid-solid growth technique (Salt 2.0) has improved the reproducibility, efficiency, and scalability of synthesizing 2D TMDCs. However, the growth of large-area MoSe2and WTe2is still quite challenging with the use of the Salt 2.0 technique. In this study, a renewed Salt 2.0 technique using mixed salts (e.g., Na2MoO4-Na2SeO3and Na2WO4-Na2TeO3) is developed for the enhanced CVD growth of 2D MoSe2and WTe2crystals with a large grain size and yield. A continuous monolayer MoSe2film with a grain size of 100-250 μm or isolated flakes up to ∼450 μm is grown on a halved 2 inch SiO2/Si wafer. Our study further confirms the synergistic effect of Na+and SeO32-in the enhanced CVD growth of the wafer-scale monolayer MoSe2film. Thus, the addition of Na2SeO3and Na2TeO3into the transition metal salts could be a general strategy for the enhanced CVD growth of many other 2D metal selenides and tellurides.
ASJC Scopus subject areas
- 化学 (全般)