Epitaxial Growth of Centimeter-Scale Single-Crystal MoS₂ Monolayer on Au(111)

Abstract

Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) have emerged as attractive platforms in next-generation nanoelectronics and optoelectronics for reducing device sizes down to a 10 nm scale. To achieve this, the controlled synthesis of wafer-scale single-crystal TMDs with high crystallinity has been a continuous pursuit. However, previous efforts to epitaxially grow TMD films on insulating substrates (<i>e.g.</i>, mica and sapphire) failed to eliminate the evolution of antiparallel domains and twin boundaries, leading to the formation of polycrystalline films. Herein, we report the epitaxial growth of wafer-scale single-crystal MoS₂ monolayers on vicinal Au(111) thin films, as obtained by melting and resolidifying commercial Au foils. The unidirectional alignment and seamless stitching of the MoS₂ domains were comprehensively demonstrated using atomic- to centimeter-scale characterization techniques. By utilizing onsite scanning tunneling microscope characterizations combined with first-principles calculations, it was revealed that the nucleation of MoS₂ monolayer is dominantly guided by the steps on Au(111), which leads to highly oriented growth of MoS₂ along the ⟨110⟩ step edges. This work, thereby, makes a significant step toward the practical applications of MoS₂ monolayers and the large-scale integration of 2D electronics.