過渡金屬硫族化合物之側向異質結構，在基礎科學與奈米元件應用上，具有相當大的潛力，其物理性質、光學和電學特性備受矚目。過去，垂直式二維材料異質結構觀察到許多有趣的物理現象，而側向式異質結構受限於材料合成，仍然是一個相當大的挑戰。其獨特的一維介面，預期將有豐富的物理特性，然而，受限於光學上空間解析度的限制，此一獨特一維異質接面仍未被深入討論。
本論文，主要針對過渡金屬硫族化合物側向式異質結構，藉由掃描式近場光學顯微術深入探討微區下之材料光學性質，透過近場光致螢光光譜及光譜掃描，觀察異質接面上的光學特性及可能的材料性質，如能階差異導致之電荷轉移。藉由化學氣相沉積法獲得之側向二維材料異質接面，其一維異質介面屬於原子級之接合，藉由掃描近場光學顯微術提升量測之空間解析度，以獲得更多局部區域的訊息。相較過去，遠場光學的相關分析，側向二維異質結構可透過近場光學獲得深入的研究。

Recently, lateral heterostructures of monolayer Transition metal dichalcogenides (TMDc) have raised considerable attentions because of their unique physical, optical and electrical properties and great potential on nano-science and nano-electronics. The study of lateral heterostructures is highly hindered because the synthesis of the sample remains a challenge issue and further study on the hetero-interface of the lateral heterostructure requires a professional optical measurement technique with sufficient spatial resolution in optics. Here, we study the optical properties of the lateral heterostructures of the two representative monolayer TMDc by scanning near-field optical microscopy (SNOM). Detailed observations and materials properties over the unique one dimensional hetero-interface, such as charge transfer, are presented with the spectra and mapping of the SNOM-PL spectroscopy. With the successful enhancements on the spatial resolution, detailed information over the localized area of the lateral hetero-junction of monolayer TMDs for its atomically-sharp hetero-interface. Compared to reported studies on confocal PL analysis, some interesting observations have been demonstrated by using SNOM.

摘要 i
Abstract ii
誌謝 iii
目錄 1
圖目錄 5
表目錄 11
第一章 緒論 12
1-1 前言 12
1-2 研究動機 13
第二章 文獻回顧 15
2-1 過渡金屬硫族氧化物(TMDc)的特性 15
2-1-1 晶體結構 15
2-1-2 能帶結構 16
2-2 化學氣相沉積法生長MoS2和WS2單晶 16
2-3 TMDc單層的光譜研究 17
2-3-1 光致螢光光譜(Photoluminescence Spectroscopy,PL)性質 17
2-3-2 拉曼光譜(Raman Spectroscopy)性質 18
2-4 單一成分TMDc單層的近場光譜研究 19
2-4-1 遠場(共軛焦)和近場光學影像解析度差異 20
2-4-2 單晶內部和邊緣的光譜比較及晶粒邊界分析 20
2-4-3 缺陷和激子分析 22
2-5 化學氣相沉積法生長單層側向MoS2/WS2異質結構 23
2-6 TMDc異質結構的光譜研究(far-field) 24
2-6-1 垂直式異質結構的光譜研究 24
2-6-2 側向式異質結構的光譜研究 26
2-6-3 混相(alloy)異質結構的光譜研究 27
2-7 TMDc的表面電位量測 30
2-7-1 載子濃度分析 30
2-7-2 材料異質結構分析 31
第三章 實驗方法 49
3-1 試片製備 49
3-1-1 化學氣相沉積法(CVD)生長 49
3-1-2 試片轉移 50
3-2 原子力顯微鏡(AFM)量測 51
3-2-1 儀器介紹 51
3-2-2 實驗原理 53
3-3 掃描凱爾文探針顯微術(SKPM)量測 55
3-4 遠場光學(Far-field)量測 57
3-4-1 儀器介紹 57
3-4-2 光致螢光光譜(photoluminescence)實驗原理 59
3-4-3 拉曼光譜實驗原理 59
3-5 掃描近場光學顯微術(SNOM)量測 60
3-5-1 實驗原理 60
3-5-2 儀器介紹 62
第四章 TMDc之表面與電性分析 71
4-1 單層WS2之分析 71
4-1-1 AFM表面形貌 71
4-1-2 SKPM電性分析 71
4-2 一階段MoS2(in)/ WS2(out)側向式異質結構之分析 72
4-2-1 AFM表面形貌 72
4-2-2 SKPM電性分析 72
4-3 Mo1-xWxS2混相(alloy)之SKPM電性分析 74
4-4 二階段WS2(in)/ MoS2(out)側向式異質結構之分析 75
4-4-1 AFM表面形貌 75
4-4-2 SKPM電性分析 76
第五章 單層二硫化鎢之光譜性質分析 84
5-1 單層WS2之遠場光學分析 84
5-2 單層WS2之近場光學分析 86
第六章 異質結構之光譜性質分析 91
6-1 一階段MoS2(in)/ WS2(out)側向式異質結構之光譜性質 91
6-1-1 遠場光學(Far-field)分析 91
6-1-2 近場光學(SNOM)分析 92
6-2 Mo1-xWxS2混相(alloy)之遠場與近場光譜性質 94
6-3 二階段WS2(in)/ MoS2(out)側向式異質結構之光譜性質 95
6-3-1 遠場光學(Far-field) 分析 95
6-3-2 近場光學(SNOM) 分析 97
第七章 結論 111
第八章 參考文獻 113

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