Growth of the twisted bilayer graphene through the two-stage chemical vapor deposition

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/83539

Title:	Growth of the twisted bilayer graphene through the two-stage chemical vapor deposition
Authors:	朱哲門;Che-Men, Chu
Contributors:	物理學系
Keywords:	化學氣相層積;石墨烯;旋轉角;拉曼光譜學;CVD;graphene;twist angle;Raman spectroscopy
Date:	2020-07-24
Issue Date:	2020-09-02 15:47:27 (UTC+8)
Publisher:	國立中央大學
Abstract:	我們通過兩階段化學氣相沉積（CVD）研究扭曲的雙層石墨烯的生長。利用協同作用的成核和生長動力學，從銅塊和氣態CHx中殘留的碳雜質中吸收碳源，在銅基體上生長了亞毫米大小的單晶石墨烯晶粒，並在其下方形成了多個合併的吸附層晶粒。通過使用微拉曼映射的光譜特徵的計算機算法研究扭轉角的分佈。除了熱力學更穩定的AB堆疊（AB-雙層石墨烯）或大角度（> 15°）解耦雙層石墨烯（DC-BLG）配置之外，還有一些雙層區域包含特定的扭曲角（3〜8°，8〜13 °和11-15°）（稱為扭曲雙層石墨烯）。統計數據表明，具有單個成核中心的雙層石墨烯沒有扭曲雙層石墨烯形成。扭曲雙層石墨烯的形成概率在很大程度上取決於合併的增加層晶粒的相對取向。在未創建扭曲雙層石墨烯域的情況下，在AB-DC合併事件中形成的晶界處發現了明顯的缺陷。扭曲雙層石墨烯的面積分數隨H2 / CH4比的增加而增加。鑑於第二層晶粒之間的相互作用，並考慮了在添加層合併過程中產生的應變，討論了扭曲雙層石墨烯的生長機理。;The research is about the growth of twisted bilayer graphene through a two-stage chemical vapor deposition (CVD). The graphene grows on Cu toward sub-millimeter-sized single crystalline graphene grains with multiple merged adlayer grains formed underneath. Developing the synergetic nucleation and growth dynamics involve carbon sources from the residual carbon impurities in Cu bulk and gaseous CHx. The distribution of the twist angles is investigated through a computer algorithm utilizing spectral features from micro-Raman mapping. Apart from the thermodynamically stable AB-stacking (AB-BLG) or large angle (> 15°) decoupled bilayer graphene (DC-BLG) configurations, some inspection of bilayer regions contain specific twist angles (3~8°, 8~13°, and 11-15°) (termed as TBLG). The statistics show no TBLG formation for BLG with single nucleation center. The formation probability of TBLG clearly reflects the orientation mismatch of merging adlayer grains. Significant defects are found at the grain boundaries formed in AB-DC merging event without creating TBLG domain. The areal fraction of TBLG increases as H2/CH4 ratio increases. The growth mechanism of TBLG is discussed in light of the interactions between the second layer grains with consideration of strain generation during the merging of adlayers.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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