自單層石墨烯被發現以來，二維材料在研究和發展上，獲得了顯著地關注。其中，具半導體性的過渡金屬二硫屬化物(TMD)，於單層時因其直接能隙、優異的電子遷移率(mobility)及開關電流比(on/off ratio)等物理特性，適用於各類光電元件、感測器等應用，有機會成為下世代之半導體或光電產業的主流材料。隨著元件尺度微小化，材料本質缺陷亦顯著影響其物理性質，因此，材料之微區分析技術逐漸成為關鍵議題。
本研究以不同二維晶體堆疊產生的各類型莫列波紋(Moire ́ pattern)為重點。實驗中成功藉由水轉移技術成功將CVD合成之TMD材料轉移至HOPG基板，進行STM分析，並深入探討材料之晶體結構、缺陷類型及分布；並以理論模型，計算各種材料堆疊及其Moire ́週期與角度的關係。此外，藉由外加偏壓的調控，觀察其相同Moire ́週期下原子影像之變化。

Since graphene was discovered, researches on two-dimensional materials has attracted a great deal of attention. Among them, transition metal dichalcogenides (TMD) semiconductors seem to be candidates for diverse applications of optoelectronic and sensors, due to their unique properties of direct bandgap, high mobility and high on/off ratio. As devices scaling down, properties of materials are significantly affected by intrinsic defects, atomic-resolved analysis thus becomes critical issues.
In this work, Moire ́ pattern resulted from different stacking of two-dimensional TMD materials has been emphasized. Monolayer TMD has been successfully transferred to the substrate (HOPG) by water-mediated transferring technique and analyzed with Scanning Tunneling Microscope (STM), for further characterization of the atomic structures and defects within materials.
Using the model of vector relation in reciprocal space, we combined the theoretical results with experimental results to calculate the relation between the periods acquired from Moire ́ pattern and misorientation angle of vertical-stacked heterostructure.

摘要 I
誌謝 III
目錄 IV
圖目錄 VI
表目錄 XI
第一章 緒論 1
第二章 文獻回顧 4
2-1 二維材料及過渡金屬硫族化合物(TMD) 4
2-1-1 成分與結構 4
2-1-2 能帶結構與能谷電子學 5
2-1-3 光學性質 7
2-1-4 製備方法 8
2-2 二維材料之掃描穿隧電子顯微術(STM) 10
2-2-1 單一二維材料之STM分析 10
2-2-2 二維材料異質結構之STM分析 13
第三章 實驗原理與方法 40
3-1 掃描穿隧電子顯微鏡簡介 40
3-1-1 STM構造 40
3-1-2 STM影像擷取 42
3-1-3 量子穿隧效應與穿隧電流 43
3-1-4 掃描穿隧電子能譜(STS) 46
3-2 超高真空系統簡介 47
3-2-1 真空幫浦及氣壓量測儀介紹 49
3-2-2 超高真空系統運作及維持 52
3-3 二維材料之基本分析 54
3-3-1 原子力顯微鏡 (Atomic Force Microscope) 54
3-3-2 拉曼(Raman)光譜與分子震動特性 54
3-3-3 光致螢光(Photoluminescence) 56
3-4 試片製備及探針製作 58
3-4-1 試片製備 58
3-4-2 STM探針製作 59
第四章 結果與討論 70
4-1 單一材料之STM分析 70
4-1-1 二維晶體之STM原子影像 70
4-1-2 STS能帶結構 71
4-2 Moire pattern影像分析 73
4-2-1 二維材料Moire pattern之理論模型與分析 73
4-2-2 異質結構之Moire pattern影像分析 77
4-2-3 偏壓對表面結構之影響 80
第五章 結論與未來展望 88
參考文獻 90

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