Effect of post-annealing on laser-ablation deposited WS2 thin films

We deposited WS2 thin films by pulsed laser deposition on sapphire substrates at room temperature, and studied the effect of post-annealing temperature on the quality of the WS2 films. By comparing the full-width-at-half-maximum of the characteristic WS2 Raman peaks, we explored the relationship between the post-annealing temperature and the crystallinity of WS2 films. Optoelectronic measurements conducted on post-annealed WS2 film-based photodetectors showed improvement with rising annealing temperatures. Our study revealed the possibility of preparing large-area dichalcogenides for optoelectronic applications.