Liquid-processed transition metal dichalcogenide films for field-effect transistors

Transition metal dichalcogenides (TMD) offer a great potential for optoelectronic devices. Yet large scale industrial application of unique TMD properties calls for facile processing techniques compatible with solution dispersible materials and printing technologies. In this work, we used wet processing technique to fabricate thin WS 2 films and field-effect devices. The films were formed at the interface of two immiscible liquids using WS 2 ethanol suspension and then were transferred onto SiO 2 /Si substrates. The wet processed WS 2 films were found to have a high residual carbon content, which was reduced by sulfur vapor annealing as assessed by XPS. Field effect transistors (FETs) fabricated using bottom-electrode configuration exhibit I on /I off ratios of 20 after annealing in the atmosphere of sulfur vapor. We conclude that TMD liquid processing can produce operational devices, but the fabrication of high-performance FETs needs to avoid organic solvents resulting in carbon contamination adversely affecting the device performance.