Ultrafast Growth of High-Quality Monolayer WSe on Au.

The ultrafast growth of high-quality uniform monolayer WSe is reported with a growth rate of ≈26 µm s by chemical vapor deposition on reusable Au substrate, which is ≈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 WSe domains in ≈30 s and large-area continuous films in ≈60 s. Importantly, the ultrafast grown WSe shows excellent crystal quality and extraordinary electrical performance comparable to those of the mechanically exfoliated samples, with a high mobility up to ≈143 cm V s and ON/OFF ratio up to 9 × 10 at room temperature. Density functional theory calculations reveal that the ultrafast growth of WSe is due to the small energy barriers and exothermic characteristic for the diffusion and attachment of W and Se on the edges of WSe on Au substrate.