Growth of Large-Area, Uniform, Few-Layer Tungsten Disulphide by Thermal Decomposition of Ammonium Tetrathiotungstate

Two-dimensional transition metal dichalcogenides (2D-TMDCs) such as molybdenum disulphide (2D-M0S2) and tungsten disulphide (2D-WS2) are now established as a class of nanomaterials that can be used in numerous applications due to their tuneable physical and chemical properties [1]. However, in terms of electrical characteristics and photoluminescence efficiency, WS2 typically exhibits superior performance compared with the molybdenum analogue [2,3]. Nevertheless, synthesis of continuous, uniform and thickness controllable 2D-WS2 films for (opto)electronic device fabrication is more challenging compared with better established 2D-MoS2 growth protocols. Therefore, the search for alternative precursors and synthesis approaches of 2D-WS2 that can provide mass production with excellent quality at low cost is highly desirable [1].