Mixed-Salt Enhanced Chemical Vapor Deposition of Two-Dimensional Transition Metal Dichalcogenides

The usage of molten salts, e.g., Na2MoO4 and Na2WO4, has shown great success in the growth two-dimensional (2D) transition metal dichalcogenides (TMDCs) by chemical vapor deposition (CVD). In comparison with halide salt (i.e., NaCl, NaBr, KI)-assisted (Salt 1.0), salt-assisted vapor-liquid-solid (VLS) technique 2.0) improved reproducibility, efficiency scalability synthesizing 2D TMDCs. However, large-area MoSe2 WTe2 is still quite challenging use Salt 2.0 technique. this study, a renewed using mixed salts (e.g., Na2MoO4-Na2SeO3 Na2WO4-Na2TeO3) developed for enhanced CVD crystals large grain size yield. Continuous monolayer film 100-250 {\mu}m or isolated flakes up to ~ 450 grown on halved 2-inch SiO2/Si wafer. Our study further confirms synergistic effect Na+ SeO32- wafer-scale film. And thus, addition Na2SeO3 Na2TeO3 into could be general strategy many other selenides tellurides.