本論文研究主要分為兩個部分 : (1)釐清新型準獨立相鍺烯結構(Quasi-freestanding phase , QP)的形成條件，包括Rectangular相以及R30˚ ± 1.1˚相。(2)研究以270˚C退火處理生長在鍺烯結構上的Au層。本研究主要使用低能電子繞射（LEED）和角分辨光電子能譜（ARPES）技術進行實驗量測。
在第一部分實驗中，我們以退火溫度270 ˚C下利用不同的Ge鍍量成功觀察到條紋相鍺烯(Striped phase , SP)會先轉變為Rectangular phase鍺烯。隨著Ge鍍量增加，結構轉變為R30˚ ± 1.1˚ phase鍺烯。這證實了除了退火溫度外，Ge沉積量也是影響新型鍺烯結構出現的關鍵因素。我們發現，在Rectangular phase與R30˚ ± 1.1˚phase鍺烯的中間狀態中，兩種相態可以共存，且在此共存態下Rectangular phase的LEED繞射點更加清晰。基於此觀察，我們重新模擬了兩種相態的晶體結構，將Rectangular phase鍺烯結構確定為晶格常數3.833 Å的QP/Ag(111)-(0.732 1.531 0.799 -0.799)，而R30˚ ± 1.1˚ phase鍺烯結構則為晶格常數3.992 Å的QP/Ag(111)-(499/361×499/361) R30˚ ± 1.1°。根據晶格的變化我們發現隨著Ge沉積量的增加Rectangular phase會釋放應力轉變為R30˚ ± 1.1˚ phase，其晶格常數更接近於freestanding鍺烯的晶格常數4.06 Å，這類似於SP轉變為QP的過程。
在第二部分實驗中，我們首先在Rectangular phase鍺烯上沉積Au原子形成一層Au薄膜，此時的LEED中可以觀察到環形繞射圖案。經過270˚C退火處理後，這個環形繞射圖案轉變為12個清晰的繞射點，這表明退火過程成功地使Au薄膜重新排列成一個更有序的結構。隨後，我們驗證了不同Au沉積量以及不同鍺烯相態相對退火後Au薄膜結構的影響。結果顯示，使用不同鍺烯相態並不影響Au薄膜的最終結構，但更多Au沉積量導致了退火Au薄膜更有序的結構，這從LEED繞射點更為清晰得到了反映。進一步通過LEED繞射點分析顯示，退火後的Au薄模具有三種結構 : (1)晶格常數3.868 Å的鍺烯結構相對於Ag(111)旋轉0度，上方具有相對於Ag(111)旋轉30度晶格常數3.349 Å的Au層；(2) 晶格常數3.75 Å的鍺烯結構相對於Ag(111)旋轉30度，上方具有相對於Ag(111)旋轉0度晶格常數3.247 Å的Au層；(3)在鍺烯孔洞中以及Ag(111)和Germanene界面上形成的晶格常數為2.88 Å的Au(111)薄膜結構。
在Core- level的光電子測量中，當Au層生長在鍺烯上時，觀察到兩組不同於原始結合能的Au峰值：Au - 4f peak (a)和Au - 4f peak (b)。Au - 4f peak (a)的結合能偏移約為0.29 eV，這是由Au與Ge界面的交互作用引起的[1]，其中Au原子佔據在了鍺烯的bridge sites上。Au - 4f peak (b)的結合能偏移約為1.02 eV，這是由於Au原子落入鍺烯的蜂窩中空中心結構中，導致更強的結合能偏移。最後，通過ARPES測量的價帶結構與我們的LEED模擬結果相互匹配，進一步證實了我們的觀察和推測。

This thesis is divided into two main parts: (1) Clarifying the formation conditions of the new Quasi-freestanding phase (QP) Germanene structures, Rectangular phase and R30˚ ± 1.1˚ phase, and (2) studying the gold (Au) layer grown on germanene structure with annealing at 270 ˚C. The study primarily utilized Low Energy Electron Diffraction (LEED) and Angle-Resolved Photoemission Spectroscopy (ARPES) for experimental measurements.
In the first part of the experiment, we observed that the Striped phase (SP) germanene first transitions into the Rectangular phase germanene under different Ge deposition amounts at an annealing temperature of 270 ˚C. With increased Ge deposition, the structure further transitions into the R30˚ ± 1.1˚ phase germanene. This confirms that, in addition to annealing temperature, the amount of Ge deposition is also a crucial factor influencing the emergence of new germanene structures. We found that in the intermediate state between Rectangular phase and R30˚ ± 1.1˚ phase germanene, both phases can coexist, and the LEED diffraction spots of the Rectangular phase are more distinct in this coexistence state. Based on this, we re-simulated the crystal structures of these two phases: the Rectangular phase germanene structure was determined to have a lattice constant of 3.833Å, represented as QP/Ag(111)-(0.732 1.531 0.799 -0.799), while the R30˚± 1.1˚ phase germanene structure had a lattice constant of 3.992 Å, represented as QP/Ag(111)-(499/361×499/361) R30˚ ± 1.1°. According to the changes in the lattice constants, we found that with the increase in Ge deposition, the Rectangular phase releases stress and transitions to the R30˚ ± 1.1˚ phase, with the lattice constant closer to that of the freestanding germanene, 4.06 Å, being similar to the process of SP transitioning to QP.
In the second part of the experiment, we initially deposited Au atoms onto the Rectangular phase germanene to form an Au layer, revealing a ring-shaped pattern in LEED. After annealing at 270 ˚C. the ring-shaped pattern transformed into 12 distinct diffraction spots in LEED, indicating that the annealing process successfully rearranged the Au layer into a more orderly structure. Subsequently, we verified the effects of Au deposition amounts and different germanene phases on the annealed Au-layer structure. The results showed that different germanene phases did not affect the final structure of Au layer, but a higher amount of Au deposition resulted in a more ordered structure as reflected from sharper LEED diffraction spots. Further analysis through LEED diffraction revealed that the annealed Au layer exhibited three structures: (1) a germanene structure with a lattice constant of 3.868 Å, rotated 0 degrees relative to Ag(111), with an Au layer on top having a lattice constant of 3.349 Å, rotated 30 degrees relative to Ag(111); (2) a germanene structure with a lattice constant of 3.75 Å, rotated 30 degrees relative to Ag(111), with an Au layer on top having a lattice constant of 3.247 Å, rotated 0 degrees relative to Ag(111); (3) an Au(111) layer structure with a lattice constant of 2.88 Å formed in the germanene pores and at the interface between Ag(111) and germanene.
In photoemission measurement of core-level states, when the Au layer was grown on germanene, two sets of Au peaks different from the original binding energy were observed: Au - 4f peak (a) and Au-4f peak (b). The binding energy shift of Au-4f peak (a) is about 0.29 eV, caused by the interaction at the Au-Ge interface[1], where Au atoms occupy the bridge sites of germanene. The binding energy shift of Au - 4f peak (b) is about 1.02 eV, caused by Au atoms falling into the honeycomb hollow centers of germanene, leading to a stronger binding energy shift. Finally, the valence band structure measured by ARPES matches our LEED simulation results, further confirming our observations and hypotheses.

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