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| 研究生： |
陳博弘 Chen, Bo-Hong |
|---|---|
| 論文名稱： |
雙層鍺烯之低能量電子繞射分析 LEED Simulation of Bilayer Germanene |
| 指導教授： |
唐述中
Tang, Shu-Jung |
| 口試委員: |
鄭弘泰
鄭澄懋 |
| 學位類別： |
碩士 Master |
| 系所名稱： |
理學院 - 物理學系 Department of Physics |
| 論文出版年： | 2021 |
| 畢業學年度： | 109 |
| 語文別： | 中文 |
| 論文頁數： | 60 |
| 中文關鍵詞： | 鍺烯 、銀(111) 、雙層鍺烯 、低能量電子繞射 |
| 外文關鍵詞： | germanene, Ag(111), bilayer germanene, LEED |
| 相關次數： | 點閱：2 下載：0 |
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在本論文中，我們使用低能量電子繞射(LEED)與角解析光電子能譜(ARPES)來研究雙層鍺烯(Bilayer Germanene)的成長，並使用鉛原子來幫助銀(111)基板上的雙層鍺烯形成，透過程式模擬LEED圖以及計算HOC(Higher-Order Coincidence)，來分析雙層鍺烯的結構。
首先，我們將鍺沉積到銀(111)基板上，隨著鍺的量增加，結構會從最初的Ag2Ge合金相轉變為條紋相SP(Striped phase)，隨後轉變為準獨立相QP(Quasi-freestanding phase)。然後我們將鉛原子沉積到QP上，在頂部形成單層鉛，其晶格結構為(√(175/124)×√(175/124))R10.16°±1。接下來我們逐步沉積鍺原子，然後退火以重新排列鉛與鍺原子。我們發現所有的鉛原子都移動到銀(111)表面並形成(√(28/19)×√(28/19))R±4.3°的結構，並擠壓QP與之並排共存。隨著鍺的鍍量來到2 ML，新的LEED訊號出現，表明雙層鍺烯的形成。根據我們的分析，雙層鍺烯有兩組晶格常數為 3.50 Å 和 4.04 Å，對應於我們觀察到的雙層鍺烯的頂部第一層和更深層的晶格結構。而AB堆疊模型的可能性更大。 ARPES 測量揭示了與基於雙層鍺烯的 AB 堆疊模型的第一性原理計算相似的帶特徵。
In this thesis, we used low-energy electron diffraction (LEED) and angle-resolved photoemission spectroscopy (ARPES) to study the growth of bilayer germanene.
We used Pb atoms to help the formation of bilayer germanene on Ag(111) and analyzed the structure of bilayer germanene by simulating the LEED patterns and calculating HOC(Higher-Order Coincidence).
First, we deposited Ge onto the Ag (111) substrate. As the amount of Ge increases, an initial Ag2Ge alloy phase transited to striped-phase (SP) germanene and subsequently evolved to quasi-freestanding phase (QP). We then deposited Pb atoms onto QP to form a monatomic Pb layer on top with the lattice structure √(175/124)×√(175/124))R10.16°±1°.Next we deposited Ge step by step, followed by annealing to rearrange the Pb and Ge atoms. We discovered that all the Pb atoms moved to Ag(111) surface forming (√(28/19)×√(28/19))R±4.3° structure to squeeze with QP germanene side by side. As the Ge amount increases to 2 ML, new LEED spots emerge indicating the formation of bilayer germanene. According to our analysis, there are two lattice constants of 3.50 Å and 4.04 Å, corresponding to lattice structures of the top first layer and deeper layers of the bilayer germanene we observed. And AB stacking model is more likely. ARPES measurement reveals the band features resembling those from the first-principles calculation based on the AB stacking model of bilayer germanene.
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