Na-assisted space-confining method for rapid growth of large-domain-size monolayer MoS2 on SiO2

Monolayer molybdenum disulfide (MoS2), a typical transition metal dichalcogenide (TMD), is a promising functional material for next-generation electronics. However, growing large-domain-sized MoS2 single crystals on SiO2 remains considerably challenging. The amorphous structure and lack of catalytic activity of SiO2 prevent the deposition of a high-quality monolayer MoS2. Herein, a Na-assisted space-confining method is deployed to directly synthesize a MoS2 single-crystal on SiO2. The domain size of MoS2 reaches 450 μm within 3 min, the fastest growth rate reported so far. This highly efficient growth is probably due to two factors: the narrow space between the sodium–calcium glass, and the SiO2 substrate controls the nucleus density; meanwhile, the release of Na from sodium–calcium glass facilitates the rapid formation of large single crystals. These results provide insights into the rapid growth of large-domain-sized TMD single crystals on amorphous substrates.