A Novel and Facile Route to Synthesize Atomic-Layered MoS₂ Film for Large-Area Electronics

High-quality and large-area molybdenum disulfide (MoS₂) thin film is highly desirable for applications in large-area electronics. However, there remains a challenge in attaining MoS₂ film of reasonable crystallinity due to the absence of appropriate choice and control of precursors, as well as choice of suitable growth substrates. Herein, a novel and facile route is reported for synthesizing few-layered MoS₂ film with new precursors via chemical vapor deposition. Prior to growth, an aqueous solution of sodium molybdate as the molybdenum precursor is spun onto the growth substrate and dimethyl disulfide as the liquid sulfur precursor is supplied with a bubbling system during growth. To supplement the limiting effect of Mo (sodium molybdate), a supplementary Mo is supplied by dissolving molybdenum hexacarbonyl (Mo(CO)₆) in the liquid sulfur precursor delivered by the bubbler. By precisely controlling the amounts of precursors and hydrogen flow, full coverage of MoS₂ film is readily achievable in 20 min. Large-area MoS₂ field effect transistors (FETs) fabricated with a conventional photolithography have a carrier mobility as high as 18.9 cm² V⁻¹ s⁻¹, which is the highest reported for bottom-gated MoS₂-FETs fabricated via photolithography with an on/off ratio of ≈10⁵ at room temperature.