MoS-OH Bilayer-Mediated Growth of Inch-Sized Monolayer MoS on Arbitrary Substrates.

Due to remarkable electronic property, optical transparency, and mechanical flexibility, monolayer molybdenum disulfide (MoS) has been demonstrated to be promising for electronic and optoelectronic devices. To date, the growth of high-quality and large-scale monolayer MoS has been one of the main challenges for practical applications. Here we present a MoS-OH bilayer-mediated method that can fabricate inch-sized monolayer MoS on arbitrary substrates. This approach relies on a layer of hydroxide groups (-OH) that are preferentially attached to the (001) surface of MoS to form a MoS-OH bilayer structure for growth of large-area monolayer MoS during the growth process. Specifically, the hydroxide layer impedes vertical growth of MoS layers along the [001] zone axis, promoting the monolayer growth of MoS, constrains growth of the MoS monolayer only in the lateral direction into larger area, and effectively reduces sulfur vacancies and defects according to density functional theory calculations. Finally, the hydroxide groups advantageously prevent the MoS from interface oxidation in air, rendering high-quality MoS monolayers with carrier mobility up to ∼30 cm V s. Using this approach, inch-sized uniform monolayer MoS has been fabricated on the sapphire and mica and high-quality monolayer MoS of single-crystalline domains exceeding 200 μm has been grown on various substrates including amorphous SiO and quartz and crystalline Si, SiC, SiN, and graphene This method provides a new opportunity for the monolayer growth of other two-dimensional transition metal dichalcogenides such as WS and MoSe.