Modulated wafer-scale WS films based on atomic-layer-deposition for various device applications.

Tungsten disulfide (WS) is promising for potential applications in transistors and gas sensors due to its high mobility and high adsorption of gas molecules onto edge sites. This work comprehensively studied the deposition temperature, growth mechanism, annealing conditions, and Nb doping of WS to prepare high-quality wafer-scale N- and P-type WS films by atomic layer deposition (ALD). It shows that the deposition and annealing temperature greatly influence the electronic properties and crystallinity of WS, and insufficient annealing will seriously reduce the switch ratio and on-state current of the field effect transistors (FETs).