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.

目錄 1
圖目錄 4
第一章 緒論 8
第二章 文獻回顧 10
2-1. 過渡金屬硫屬化物(TMDCs)介紹 10
2-1-1晶體結構 10
2-1-2電子能帶結構 10
2-1-3 能谷電子學(Valleytronics) 11
2-1-4光學性質 11
2-2. 過渡金屬硫屬化物(TMDCs)製備方法 13
2-2-1 機械剥離法 13
2-2-2 化學離子插層法 13
2-2-3化學氣相沉積法 14
2-3. 過渡金屬硫屬化物異質結構 14
2-3-1 二維材料異質結構的製備 14
2-3-2垂直式異質結構 15
2-3-3 側向式異質結構 16
2-3-4 合金相異質結構 17
第三章 實驗方法 27
3-1 實驗大綱 27
3-2實驗系統 28
3-2-1試片處理 28
3-2-2 實驗步驟 28
3-3 材料分析與量測 30
3-3-1 光學顯微鏡 30
3-3-2 拉曼光譜儀 30
3-3-3 光致螢光光譜 31
3-3-4 二次諧振波 32
3-3-5 原子力顯微鏡 32
第四章 二硫化鎢的合成與分析 38
4-1 製程參數對二硫化鎢的影響 38
4-1-1 反應物濃度(三氧化鎢與硫)對於生長的影響 38
4-1-2 還原氣氛對於合成的影響 40
4-1-3 造成結晶形狀改變的原因 41
4-1-4 晶種(PTAS)濃度對於生長的影響 41
4-2 單層二硫化鎢的轉移方法 46
4-3 二硫化鎢的光學性質 47
4-4 二硫化鎢的電學與光電特性 48
4-4-1 二硫化鎢的電性量測結果 48
4-4-2 光響應(photo-responsivity, R) 48
第五章 二硫化鎢異質結構的合成與分析 62
5-1 二硫化鎢異質結構 62
5-2 一階段製程合成異質結構 62
5-2-1 二硫化鉬/二硫化鎢異質結構之合成 62
5-2-2 二硫化鉬/二硫化鎢異質結構之特性檢測 64
5-2異質結構合金相 65
5-3 二階段製程合成異質結構 66
第六章 結論 77
附錄: 期刊發表與研究獲獎 78
參考文獻 79
 

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