在碳化矽基板上成長石墨烯並藉由角解析光電子能譜術了解其電子結構

Growth of few layer graphene on SiC surface and characterization of their electronic structure by angle-resolved photoemission

鄧君浩(Jun-Hao Deng)

指導教授 ： 崔古鼎

國立清華大學/理學院/物理學系/碩士(2013年)

摘要

石墨烯是由一層碳原子排列成的二維蜂巢狀結構。因具備高載子遷移率、高晶格品質和經濟的價值，石墨烯被認為是下一代元件裡面具有低尺度的材料，且在未來將扮演提昇奈米技術的重要角色。在此論文中，我成功地在碳化矽基板上長出高品質的雙層石墨烯，並藉由角解析光電子能譜術探測其電子結構。我們由緊束縛模型(tight-binding model)分析在碳化矽基板上成長的一層及雙層石墨烯的實驗數據得到良好的擬合結果。從緊束縛模型擬合的結果我們得知一層以及雙層石墨烯在碳化矽基板上打開能隙的原因是因為單位晶格中兩顆碳原子的位能不同。而雙層石墨烯不僅僅是因為兩個碳原子位能不同，還有層與層之間位能不同的因素打開了能隙。在此我們利用一系列不同的入射光能量造成各個能帶強度上的震盪變化以決定出雙層石墨烯在碳化矽基板上其層與層之間的距離。我們的結果是雙層石墨烯在碳化矽基板上其層與層之間的距離為3.31埃，略小於石墨層與層間的距離。

關鍵字

石墨烯

並列摘要

Graphene consists of a single layer carbon atoms packed in a 2D honeycomb structure. It is very highly promising as a low-dimensional material for the next generation devices owing to its high carrier mobility, high crystal quality and economic price. It will be playing an important role to improve the nanotechnology in the future. In this thesis, I successfully grow high quality bilayer graphene on 6H-SiC and use the Angle-resolved photoemission spectroscopy (ARPES) to probe its electronic structure. We obatin a good fitting result by a tight-binding (TB) model in SLG/SiC and BLG/SiC. Importantly, the on-site energy difference caused the gap opening in SLG/SiC and BLG/SiC can be realized by TB fitting. The reason of the gap opening in BLG/SiC is not only attributed to the difference in on-site energy between different carbon atom sites in the same graphene layer, but also originates from the energy difference between different graphene layers. The interlayer spacing of BLG/SiC can be determined from the oscillation period of photoemission intensity for different photon energies. Our result of interlayer spacing d = 3.31 Å for BLG/SiC is slightly smaller than the value in bulk graphite.

並列關鍵字

Graphene

參考文獻

chapter 1

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