近幾年來，二維過渡金屬硫屬化物因其新穎的物理特性與化學性質而備受重視。本論文中，主要使用化學氣相沉積法結合晶種以促進二硫化鎢薄膜於二氧化矽基板和藍寶石基板上的合成反應。並藉由晶種濃度與還原氣氛氫氣的流量控制來調整薄膜的合成面積及二硫化鎢單晶的結晶形狀。
過渡金屬硫屬化物原子級異質結構具有特殊的光電特性，可應用於下一世代的光電元件材料。本論文藉由合成二維材料的基礎，提出使用一階段製程以及二階段製程法的方式合成出單層二硫化鎢與二硫化鉬的異質結構。此類異質結構的特性會受到相位、材料結構對稱性及材料介面處影響，在異質結構的原子影像中可觀察到，相異兩材料的介面沿著材料Zia-Zag結晶方向進行磊晶成長。同時，也可藉由控制兩種材料混合比例達到調整其能隙大小。

In recent years, there has been an increasing interest in Two-dimensional semiconducting transition metal dichalcogenides (TMDs) because of their novel physical and chemical properties.
In this work, we demonstrated the synthesis of high quality single crystal WS2 and large-area films on sapphire and SiO2 substrate using ambient chemical vapor deposition(CVD) with aromatic molecules as seeding promoters. The coverage and domain size of WS2 were controlled by the concentration of seeding promotor and adjusting the flow rate of H2 carrier gas.
Atomically thin heterostructures of TMDs with novel electric properties and optical characteristic are the key material of next generation flexible nanoelectronics. Here, based on the previous work of the synthesis of TMDs, we demonstrate one step and two step synthesis of lateral heterostructures of monolayer TMDs. The diverse performances of these heterostructure are significantly determined by phases, symmetry and interface quality. In atomic-resolution images, a uniform lateral growth along the MX2 is observed and the interface of lateral heterostructures picks the zigzag direction of the lattice. Meanwhile, we can control the bandgap energy by adjusting the ratio of the composition.

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