One-step Synthesis of Few-layer WS(2) by Pulsed Laser Deposition

Atomically thin tungsten disulfide (WS(2)) has attracted much attention in recent years due its indirect-to-direct band gap transition, band gap tunability, and giant spin splitting. However, the fabrication of atomically thin WS(2) remains largely underdeveloped in comparison to its structural analogue MoS(2). Here we report the direct fabrication of highly crystalline few-layer WS(2) on silver substrates by pulse laser deposition at the relatively low temperature of 450 °C. The growth takes places by conventional epitaxy, through the in-situ formation of nearly lattice-matching Ag(2)S on the silver surface. Intriguingly, it was observed that the resulting film was composed of not only the usual semiconducting 2H-WS(2) structure but also the less common metallic 1T-WS(2). Modifications of the synthesis parameters allow for control over the crystalline quality, film thickness and crystal phase composition of the resulting WS(2) film.