Ultrafast Growth of High-Quality Monolayer WSe2 on Au

The ultrafast growth of high-quality uniform monolayer WSe2 is reported with a growth rate of approximately 26 microm s(-1) by chemical vapor deposition on reusable Au substrate, which is approximately 2-3 orders of magnitude faster than those of most 2D transition metal dichalcogenides grown on nonmetal substrates. Such ultrafast growth allows for the fabrication of millimeter-size single-crystal WSe2 domains in approximately 30 s and large-area continuous films in approximately 60 s. Importantly, the ultrafast grown WSe2 shows excellent crystal quality and extraordinary electrical performance comparable to those of the mechanically exfoliated samples, with a high mobility up to approximately 143 cm(2) V(-1) s(-1) and ON/OFF ratio up to 9 x 10(6) at room temperature. Density functional theory calculations reveal that the ultrafast growth of WSe2 is due to the small energy barriers and exothermic characteristic for the diffusion and attachment of W and Se on the edges of WSe2 on Au substrate.