揭露扭曲雙層石墨烯的生長機制：層間和層內相互作用;Unveiling the Growth Mechanism of Twisted Bilayer Graphene: Interlayer and Intralayer Interactions

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題名:	揭露扭曲雙層石墨烯的生長機制：層間和層內相互作用;Unveiling the Growth Mechanism of Twisted Bilayer Graphene: Interlayer and Intralayer Interactions
作者:	朱哲門;Chu, Che-Men
貢獻者:	物理學系
關鍵詞:	石墨烯;旋轉角;層內作用;拉角解析度;角解析度光電子能譜;graphene;twist angle;intralayer interaction;Raman spectroscopy;Angle-resolved photoemission spectroscopy
日期:	2023-11-15
上傳時間:	2024-09-19 15:56:24 (UTC+8)
出版者:	國立中央大學
摘要:	本研究通過分析化學氣相沉積過程中與層間和層內相互作用相關的因素，探究了扭轉雙層石墨烯的生長機制。生長過程發生在銅基底上，形成亞毫米級的單晶石墨烯晶粒，並在下方形成多個合併的附屬層晶粒。生長動力學包括協同成核，並利用銅基底中殘餘碳雜質和氣態碳氫化合物作為碳源。採用計算機算法和微米激光拉曼技術研究了石墨烯的扭轉角分佈。根據統計數據，在考慮單個成核中心的雙層區域中，除了熱力學穩定的AB堆疊或分離雙層石墨烯，沒有形成具有特定扭轉角（3°至8°，8°至13°和11°至15°）的扭轉雙層石墨烯。扭轉雙層石墨烯形成的概率受到合併附屬層晶粒的取向失配的影響，層間和層內相互作用在決定扭轉角方面起著關鍵作用。層間相互作用涉及熱膨脹差異引起的變形和層與基底之間的分離，導致扭轉角的範圍受到限制。對相關變形的高度分析以及銅基底上石墨烯的能帶結構顯示出層間僅存在輕微的不匹配。扭轉雙層石墨烯的發生還與生長速率變化有關，同位素標記實驗導致拉曼特徵峰的偏移。通過考察附屬層晶粒之間的相互作用並考慮在合併過程中發生的生長速率變化，分析了扭轉雙層石墨烯的生長機制。提出了與使用不同邊緣的合併配置相關的新模型，改善了我們對扭轉雙層石墨烯的生長機制的理解。生長速率和一系列合併配置都會影響TBLG的概率和面積占比。極端的生長條件，特別是高梯度的碳源和較短的成核距離，已被發現能夠有效地提高扭轉雙層石墨烯的生長速率並增加其面積占比。;This research investigates the growth mechanism of twisted bilayer graphene (TBLG) by analyzing the factors related to interlayer and intralayer interactions during chemical vapor deposition (CVD). The growth process occurs on a copper substrate, resulting in the formation of sub-millimeter-sized single crystalline graphene grains with merged adlayer grains beneath. The growth dynamics involve synergistic nucleation and utilize carbon sources from residual carbon impurities in the copper substrate as well as gaseous hydrocarbons (CHx). The distribution of twist angles in the graphene is studied using a computer algorithm and micro-Raman mapping. Based on the statistical, apart from the thermodynamically stable AB-stacking (AB-BLG) or decoupled bilayer graphene (DC-BLG), there is no formation of twisted bilayer graphene (TBLG) with specific twist angles ranging from 3° to 8°, 8° to 13°, and 11° to 15° when considering bilayer regions with a single nucleation center. The probability of TBLG formation is influenced by the orientation mismatch of merging adlayer grains, and the interlayer and intralayer interactions play a crucial role in determining the twist angle. The interlayer interaction involves deformation resulting from thermal expansion differences and decoupling between layers and the substrate, resulting in a confined range of twist angles. Height analysis of the associated deformation, as well as the band structure of graphene on the copper substrate, indicate only a small mismatch at the interlayer. The occurrence of TBLG is also related to the growth rate variation, as evidenced by the use of isotopic labelling, which induces peak shifts in Raman characteristics. The growth mechanism of twisted bilayer graphene (TBLG) is analyzed by examining the interactions between adlayer grains and taking into account the variations in growth rate that occur during the merging process. Novel modules associated with merging configurations employing distinct edges are proposed, improving our understanding of the growth mechanism of TBLG. The probability and areal fraction of TBLG are influenced by both growth rate and a series of merging configurations. Extreme growth conditions, characterized by high source gradients and short nucleation distances, have been found to effectively increase the growth rate of TBLG and enhance its areal fraction.
顯示於類別:	[物理研究所] 博碩士論文

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