Selective Area Growth and Transfer of High Optical Quality MoS₂ Layers

This study demonstrates that monolayer molybdenum disulfide (MoS₂) can be grown on selective areas of a substrate by creating isolated microcavity reactors throughout the substrate in a chemical vapor deposition (CVD) process. The obtained MoS₂ in the confined areas can be tuned from isolated triangular domains of few tens of microns to a continuous film with different thicknesses by modulating the growth parameters. In contrast, the growth on the open areas of the substrate leads to an inhomogeneous film. Using the confined-CVD approach, the area-selective growth of MoS₂ domains and films on arbitrary substrates such as SiO₂/Si, sapphire, gold-patterned SiO₂/Si substrates, and SiN_x-membrane-supported TEM grid is shown. Raman and photoluminescence spectroscopy studies reveal that the confined-CVD-derived MoS₂ layers have high crystal quality and superior optical performance when compared to mechanically exfoliated flakes. A novel and efficient methodology is further introduced for the selective transfer of the confined-growth areas to pre-patterned substrates, therefore allowing multiple use of a single growth sample. Finally, field-effect transistor devices are made on individual domains and mobilities up to ≈6.8 cm² V⁻¹ s⁻¹ measured. The confined-CVD approach and the selective area transfer presented here can be implemented on other transition metal dichalcogenides and 2D materials in general.