Abbas Omar A, Zeimpekis Ioannis, Wang He, Lewis Adam H, Sessions Neil P, Ebert Martin, Aspiotis Nikolaos, Huang Chung-Che, Hewak Daniel, Mailis Sakellaris, Sazio Pier
Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
National Centre for Advanced Tribology, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
Sci Rep. 2020 Feb 3;10(1):1696. doi: 10.1038/s41598-020-58694-0.
Unlike MoS ultra-thin films, where solution-based single source precursor synthesis for electronic applications has been widely studied, growing uniform and large area few-layer WS films using this approach has been more challenging. Here, we report a method for growth of few-layer WS that results in continuous and uniform films over centimetre scale. The method is based on the thermolysis of spin coated ammonium tetrathiotungstate ((NH)WS) films by two-step high temperature annealing without additional sulphurization. This facile and scalable growth method solves previously encountered film uniformity issues. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to confirm the few-layer nature of WS films. Raman and X-Ray photoelectron spectroscopy (XPS) revealed that the synthesized few-layer WS films are highly crystalline and stoichiometric. Finally, WS films as-deposited on SiO/Si substrates were used to fabricate a backgated Field Effect Transistor (FET) device for the first time using this precursor to demonstrate the electronic functionality of the material and further validate the method.
与金属氧化物半导体（MoS）超薄薄膜不同，基于溶液的单源前驱体合成方法在电子应用中已得到广泛研究，而使用这种方法生长均匀且大面积的少层WS薄膜则更具挑战性。在此，我们报告一种生长少层WS的方法，该方法可在厘米尺度上得到连续且均匀的薄膜。该方法基于通过两步高温退火对旋涂的四硫代钨酸铵（(NH)WS）薄膜进行热解，无需额外硫化。这种简便且可扩展的生长方法解决了先前遇到的薄膜均匀性问题。使用原子力显微镜（AFM）和透射电子显微镜（TEM）来确认WS薄膜的少层性质。拉曼光谱和X射线光电子能谱（XPS）表明，合成的少层WS薄膜具有高度结晶性和化学计量比。最后，首次使用这种前驱体将沉积在SiO/Si衬底上的WS薄膜用于制造背栅场效应晶体管（FET）器件，以展示该材料的电子功能并进一步验证该方法。
