早先的研究預測生長於Si(111)-√3✕√3-R30°-Au的鉍蜂巢狀結構(Bi honeycomb structure)具有二維拓樸絕緣體(2D-topological insulator)的性質。STM的結果也近一步應證了鉍確實能在修飾後的矽(111)表面上形成蜂巢狀結構。然而作為實驗上的證據，目前仍未有傅立葉轉換-掃描式穿隧電子能譜(FT-STS)的結果。
對此，在相關的文獻中曾提及，由於會影響到傅立葉轉換後數據的解析度，在進行一維邊緣(edge)的電子態量測時，需要在筆直且沒有缺陷(disorder-free)的邊緣進行。然而在鉍蒸鍍於理論所預測的Au/Si(557) -√3基板後，其邊緣是蜿蜒無規的(meandering)。因此為了嘗試要生長具有長直邊緣的帶狀鉍(Bismuthribbon)，我們使用了在原子尺度下仍保有規律性的斜切矽基板Si(557)。
在本研究中，我們透過超高真空(1.0✕10-10Torr) 的環境，分別利用低能量電子繞射儀LEED，以及掃描穿隧式電子顯微鏡STM 觀察鉍於Au/Si(557) -√3基板的生長行為，希望可以提供階梯狀的斜切基板做為生長二維拓樸材料的襯底，並進一步改善其邊緣電子態量測的解方。

The Bi honeycomb grown on Si(111)-√3✕√3-R30°-Au substrate has already been predicted as two-dimensional topological Insulators[5]. STM result also shown that Bi form honeycomb structure on top of Au/Si(111) -√3 substrate, which is coincident with the calculation. Experimentalists also try many efforts on the confirmation of its topological edges state by using Fourier-Transform Scanning Tunneling Spectroscopy.

For this concern, previous studies mention that when probing 1D edge electronic state, remarkably straight and disorder-free edge is required. This will influence the resolution of the Fourier transformed data. However, at the system of Au/Si (111) -√3, upon the deposition, initial observation of the image of Bi island shown that its edge is meandering. Therefore, to realize the observation of the surface state of Bi nanoribbon, atomically ordered vicinal surfaces were well prepared as the substrate.

In this study, then, the growth behavior of Bi on Au/Si(557) -√3 substrates is investigated by scanning tunneling microscopy and low energy electron diffraction experiment in the ultrahigh vacuum system (1.0✕10-10 Torr base pressure). This finding may suggest a viable way for using stepped surfaces with atomically accurate hill and valley structures as a potential route for observing QPI on 2D Ti platforms.

論文審定書i
論文公開授權書ii
誌謝iii
摘要iv
英文摘要v
1 簡介1
2 原理及性質 5
2.1 拓撲絕緣體(Topological insulator) . . . . . . . . . . . . . . . . . . . . 5
2.2 驗證二維拓撲絕緣體的實驗方法. . . . . . . . . . . . . . . . . . . . . 7
2.3 斜切矽基板表面的自組裝結構. . . . . . . . . . . . . . . . . . . . . . 10
3 實驗儀器及原理 13
3.1 實驗環境-超高真空系統(UHV) . . . . . . . . . . . . . . . . . . . . . . 13
3.1.1 系統配置與真空簡介. . . . . . . . . . . . . . . . . . . . . . . 13
3.1.2 真空量測技術. . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1.3 真空抽氣技術. . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.1.4 腔體處理技術. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2 樣品制備與處理. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.1 斜切矽基板. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.2 物理氣相沉積(PVD)技術. . . . . . . . . . . . . . . . . . . . . 24
3.2.3 熱處理(thermal treatment) . . . . . . . . . . . . . . . . . . . . 26
3.2.4 離子濺射(ion sputtering) . . . . . . . . . . . . . . . . . . . . . 26
3.3 表面晶體學(surface crystallography)量測技術. . . . . . . . . . . . . 27
3.3.1 低能電子繞射儀(LEED) . . . . . . . . . . . . . . . . . . . . . . 28
3.3.2 掃描式穿隧電子顯微鏡(STM) . . . . . . . . . . . . . . . . . . 35
4 實驗結果與討論 41
4.1 階梯狀矽基板的備製. . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2 金緩衝層於Si(557)表面的成長行為與結構分析. . . . . . . . . . . . . 48
4.3 鉍蒸鍍於Au/Si(557) 表面的生長與形貌分析. . . . . . . . . . . . . . 52
4.4 斜切基板對於邊界態量測的應用. . . . . . . . . . . . . . . . . . . . . 62
5 結論 63
參考文獻 65

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