本論文主要著重在二碲化鎢(WTe2)的合成機制以及性質的探討。二碲化鎢由於其特殊的結構以及在低溫高磁場下具有不飽和的巨大磁阻特性因而受到重視，本研究利用化學氣相沉積法(CVD)合成WTe2，並透過不同參數的調控來觀察對材料生長的影響，包含不同的鹼金屬鹵化物、基板的種類、還原氣氛(氫氣)以及反應物的位置等，進一步優化實驗的參數而獲得大面積的二碲化鎢，最後做成元件並量測到目前透過CVD方法取得的二碲化鎢中，最高的磁阻效應。

In this research, we focus on the growth mechanism and the physical properties of tungsten telluride. Tungsten telluride have attracted tremendous interests recently due to its unique structure and large non-saturating magnetoresistance properties. Here we demonstrate a CVD method to directly synthesize large scale WTe2.The high quality of few layer WTe2 was confirmed via optical microscopy, atomic force microscopy(AFM) and Raman spectroscopy. And finally our device exhibited an excellent magnetoresistance compared with previous study.

目錄 1
圖目錄 3
第一章 緒論 5
第二章 文獻回顧 7
2-1 過渡金屬硫族化合物 7
2-1-1 晶體結構 7
2-1-2 能帶結構 9
2-1-3 磁阻特性 11
2-1-4 相變化特性 12
2-2 過渡過渡金屬硫族化合物製備方法 12
2-2-1 機械剝離法 12
2-2-2 化學離子插層 13
2-2-3 物理氣相沉積法 13
2-2-4 化學氣相傳輸法 14
2-2-5 化學氣相沉積法 14
2-3 化學氣相沉積法合成二維材料的重要參數 15
2-3-1 溫度 15
2-3-2 還原氣氛對結晶影響 16
2-3-3 化學反應途徑對材料生長的影響 16
2-4 二維材料分析與檢測 19
2-4-1 拉曼光譜分析 19
2-4-2 二次諧振波(Second Harmonic Generation, SHG) 21
第三章 實驗方法 31
3-1 實驗大綱 31
3-2 實驗系統 31
3-2-1 試片處理 31
3-2-2 實驗步驟 31
3-3 材料分析與量測 33
3-3-1 光學顯微鏡 33
3-3-2 拉曼光譜分析 33
3-3-3 二次諧振波量測 33
3-3-4 表面形貌與厚度分析 34
3-3-5 X光光電子能譜儀 34
3-3-6 電性量測 34
3-3-7 磁阻量測 35
第四章 二碲化鎢的合成與分析 38
4-1 製程參數對二碲化鎢生長影響 38
4-1-1 鹼金屬鹵化物對材料生長的影響 38
4-1-2 基板種類對生長影響 40
4-1-3 還原氣氛(氫氣) 41
4-1-4 Te 反應物進入的時間 42
4-1-5 持溫時間 43
4-1-6 總結 44
4-2 二碲化鎢的磁阻量測以及光學分析 45
4-2-1 材料的穩定性 45
4-2-2 磁阻量測結果 45
4-2-3 偏振拉曼分析與SHG 46
第五章 結論 61
附錄: 期刊發表(與研究獲獎) 62
第六章 參考文獻 63

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