Atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising candidates for future electronics. Currently, the growth of TMD large area thin films/flakes is one of the biggest challenges. A novel method for the growth of ultra-thin and large area WS₂ monolayer flakes has been developed by introducing a solution-based temperature-dependent process. This two-dimensional WS₂ growth process is low cost and environmentally friendly. WO₃ flakes are grown at the air–liquid interface using ammonium tetrathiotungstate ((NH₄)₂WS₄, ATTW) as WS₂ precursor. The process requires a moderate activation temperature as no flakes are formed at room temperature. Successful growth of flakes was observed in an aqueous solution of the precursor at a temperature between 70 C and 90 C. These flakes could be transferred to any substrate by a controlled dip-coating process. Large 2D WS₂ flakes with a lateral size of up to 100 μm were obtained after sulfurization. The thickness ranged from a WS₂ monolayer to five monolayers, as verified by atomic force microscope. The chemical reaction mechanism behind the formation of the flakes was investigated by FTIR, Raman, UV–Vis and x-ray photoelectron spectroscopy. The initial flakes were found to be made of WO₃, which were successfully converted to WS₂ by a post annealing step at 500 C–900 C. This simple and environmentally friendly growth technique can be used to produce large WS₂ flakes for next generation electronics.

原子薄的二维（2D）过渡金属二硫化二氢（TMD）是未来电子产品的有希望的候选者。当前，TMD大面积薄膜/薄片的增长是最大的挑战之一。通过引入基于溶液的温度依赖性过程，已经开发了一种用于生长超薄和大面积WS ₂单层薄片的新颖方法。二维WS _2的生长过程成本低廉且对环境友好。WO ₃薄片使用四硫钨酸铵（（NH ₄）₂ WS ₄，ATTW）作为WS ₂在气液界面生长前体。该方法需要适中的活化温度，因为在室温下不会形成薄片。在前体的水溶液中，在70℃至90℃之间的温度下观察到薄片的成功生长。可以通过控制浸涂工艺将这些薄片转移到任何基材上。大2D WS _2个薄片具有高达100的横向尺寸μ硫化后得到米。通过原子力显微镜验证，厚度范围从WS ₂单层到五个单层。通过FTIR，拉曼光谱，UV-Vis和X射线光电子能谱研究了薄片形成背后的化学反应机理。发现最初的薄片是由WO ₃制成的，将其成功地转换为WS ₂通过后退火步骤在500℃-900℃。该简单和环保的生长技术可用于产生大量的WS _2个薄片为下一代电子。