在本論文的研究中，我嘗試在晶格結構為Ag(111)-√3×√3 R〖30〗^°的Ag_2 Pb表面合金上製作雙層鍺烯結構，且以低能量電子繞射(low-energy electron diffraction; LEED)和光電子能譜(Photoemission spectroscopy; PES)來研究晶格結構和電子能譜。在最初蒸鍍Ge原子時，我們發現在不同的退火條件下QP(Quai-freestanding phase)鍺烯能夠形成兩種組態，第一種是在特定角度範圍內有連續多個區域分布的情況，第二種為比較有序的QP鍺烯角度區域固定在相對Ag(111)-√3×√3 R〖30〗^°基底旋轉±3^°度。我們接著分別在這兩種結構上交替蒸鍍上Pb和Ge原子來製作雙層鍺烯結構。透過實驗我發現了雙層鍺烯能夠在前者上成形但在後者卻無法有效地形成結構。
透過檢視了QP鍺烯在Ag(111)上的HOC(higher-order-coincidence)點的密度，我們發現了分裂±3^°度的QP鍺烯在各種角度分布中是最穩定的，所以我們推斷當蒸鍍更多的Pb和Ge原子時，最初在Ag(111)上穩定的QP鍺烯會阻礙隨後的雙層鍺烯生長。與之相反，如果初始的QP鍺烯穩定性較差，例如在特定角度範圍內有連續多個區域分布的情況，在蒸鍍更多的Pb和Ge原子後，能夠更靈活地透過應變效應來進一步的演變為雙層鍺烯。

In the research work of this thesis, I attempted to grow bilayer germanene on the Ag2Pb alloy surface with the lattice structure Ag(111)- and investigated the resulting lattice and electronic structures by low-energy electron diffraction (LEED) and photoemission spectroscopy (PES). Upon initial Ge deposition, we found germanene of quasi-freestanding phase (QP) can form in two configurations, QP with multiple domains rotating continuously within a certain angle range, and more ordered QP with only two domains locked into 3 rotation with respect to Ag(111)- , depending on the annealing conditions. We then alternatively deposit Pb and Ge onto these two templates, respectively to form bilayer germanene. I discovered that bilayer germanene can form for the former but cannot for the latter.

By checking the density of higher-order-coincidence (HOC) points for QP germanene on Ag(111), we find QP with only two domains locked into 3 is most stable so we reason that the initial stable QP germanene on Ag(111) is against the subsequent growth to bilayer germanene when more Pb and Ge atoms are deposited. On the contrary, if the initial QP germanene is less sable such as the case of multiple domains rotating continuously within a certain angle range, it is more flexible to undergo strain effect to further evolve to bilayer germanene after depositing more Pb and Ge atoms.

摘要…………………………………………………………………………………….i
Abstract………………………………………………………………………………..ii
目錄…………………………………………………………………………………...iii
第一章 緒論……………………………………………………………………...…...1
第二章 背景知識…………………………………………………………………......2
2.1 晶體結構………………………………………………………………...2
2.1.1 Ag(111)………………………………………………………………2
2.1.2 倒晶格………………………………………………………………5
2.1.3 蜂巢狀結構…………………………………………………………7
2.2 表面……………………………………………………………………...7
2.2.1 表面布里淵區………………………………………………………8
2.2.2 表面態………………………………………………………………8
2.2.3 Wood’s notation……………………………………………………10
2.2.4 單層(Monolayer)…………………………………………………..10
2.2.5 莫瑞條紋(Morié pattern)…………………………………………..11
2.3 光電子能譜…………………………………………………………….11
2.3.1 光電效應…………………………………………………………..11
2.3.2 基本原理…………………………………………………………..12
2.3.3 角解析光電子能譜(ARPES)……………………………………...16
第三章 實驗儀器介紹………………………………………………………………18
3.1 超高真空(UHV)………………………………………………………..18
3.1.1 實驗環境(超高真空系統)………………………………………...20
3.1.2 幫浦介紹…………………………………………………………..21
3.2 蒸發器……………………………………………………………….....22
3.3 低能量電子繞射(LEED)………………………………………………23
3.4 光子來源……………………………………………………………….24
3.4.1 氦燈(Helium lamp)………………………………………………..24
3.4.2 同步輻射…………………………………………………………..25
3.5 能量分析儀…………………………………………………………….26
第四章 實驗背景……………………………………………………………………29
4.1 Ge在Ag(111)上的成長……………...…...……………………………29
4.1.1條紋相鍺烯(Stripe phase germanene ; SP)………………………...32
4.1.2 準獨立相鍺烯(Quasi-freestanding phase germanene ; QP)………34
4.2 透過Pb原子增強鍺烯結構…………………………..……………….36
4.3 交換在Ag(111)上鍍Pb與Ge的順序……………….……………….40
第五章 實驗結果與分析……………………………………………………………43
5.1 動機…………………………………………………………………….43
5.2 實驗內容……………………………………………………………….45
5.2.1 樣品製作過程中, 蒸鍍同時以100℃退火………………………45
5.2.2 樣品製作過程中, 蒸鍍同時以150℃退火………………………50
5.2.3 在製作出±3^°分裂的QP鍺烯後改以先蒸鍍後以150℃退火..…54
5.3 結果討論……………………………………………………………….58
結論…………………………………………………………………………………..59
參考資料……………………………………………………………………………..60

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