Abstract:
The growth of large-scale 2D transition metal dichalcogenides is essential for a range of electronic and energy applications. However, achieving controllable, reproducible, uniform, and large-area ultrathin films, along with doping and alloying, remains challenging, emphasizing the need for versatile growth methods. To address this, this talk reports a membrane-controlled vapor-liquid-solid (VLS) growth method that produces continuous bilayer molybdenum vanadium sulfide with sulfur vacancies (Svac-Mo1-xVxS2) alloy films. By optimizing the thickness of solid precursors and membrane layer, as well as the growth temperature, we demonstrate precise control over film thickness and alloying element concentration. Our results reveal the presence of the V–Svac pairs, manifesting in the vacancy concentration and change in the optical properties. Furthermore, the bilayer film displays a boosted CO2 photoreduction yield, attributing to the efficient bind of reactants on V–Svac pair active sites, a suitable energy band diagram, increased light absorption, and improved charge transfer/transport.