Fast growth of large-grain and continuous MoS<sub>2</sub> films through a self-capping vapor-liquid-solid method.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32703950.
- Also identified by DOI 10.1038/s41467-020-17517-6 and PMC identifier 7378841.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Most chemical vapor deposition methods for transition metal dichalcogenides use an extremely small amount of precursor to render large single-crystal flakes, which usually causes low coverage of the materials on the substrate. In this study, a self-capping vapor-liquid-solid reaction is proposed to fabricate large-grain, continuous MoS<sub>2</sub> films. An intermediate liquid phase-Na<sub>2</sub>Mo<sub>2</sub>O<sub>7</sub> is formed through a eutectic reaction of MoO<sub>3</sub> and NaF, followed by being sulfurized into MoS<sub>2</sub>. The as-formed MoS<sub>2</sub> seeds function as a capping layer that reduces the nucleation density and promotes lateral growth. By tuning the driving force of the reaction, large mono/bilayer (1.1 mm/200 μm) flakes or full-coverage films (with a record-high average grain size of 450 μm) can be grown on centimeter-scale substrates. The field-effect transistors fabricated from the full-coverage films show high mobility (33 and 49 cm<sup>2</sup> V<sup>-1</sup> s<sup>-1</sup> for the mono and bilayer regions) and on/off ratio (1 ~ 5 × 10<sup>8</sup>) across a 1.5 cm × 1.5 cm region.