Synthesis of centimeter-scale monolayer tungsten disulfide film on gold foils

We report the synthesis of centimeter-scale monolayer WS₂ on gold foil by chemical vapor deposition. The limited tungsten and sulfur solubility in gold foil allows monolayer WS₂ film growth on gold surface. To ensure the coverage uniformity of monolayer WS₂ film, the tungsten source-coated substrate was placed in parallel with Au foil under hydrogen sulfide atmosphere. The high growth temperature near 935 °C helps to increase a domain size up to 420 μm. Gold foil is reused for the repeatable growth after bubbling transfer. The WS₂-based field effect transistor reveals an electron mobility of 20 cm² V^-1 s^-1 with high on-off ratio of ∼10⁸ at room temperature, which is the highest reported value from previous reports of CVD-grown WS₂ samples. The on-off ratio of integrated multiple FETs on the large area WS₂ film on SiO₂ (300 nm)/Si substrate shows within the same order, implying reasonable uniformity of WS₂ FET device characteristics over a large area of 3 × 1.5 cm².