氫嵌入石墨烯之電子傳輸特性和幾何相位研究

Study on electrical transport properties and geometric phase in hydrogen-intercalated epitaxial graphene

施政榮(Cheng-Jung Shih)

指導教授 ： 梁啟德

國立臺灣大學/理學院/物理研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.02305

摘要

石墨烯作為一種在拓展摩爾定律、以及在新物理的發現上很有潛力的材料，近年研究發展的相當迅速。在各種研究項目中，碳化矽表面外延生長的石墨烯，因其大面積及高品質，受到了許多的注目。在本篇論文中，研究了氫嵌入過程的碳化矽表面外延生長的石墨烯，在低溫、高磁場下的載子傳輸特性。在論文前面的部分，首先介紹石墨烯的晶格及能帶特性，以及在二維電子系統中，會出現的電子傳輸特性；接著介紹氫嵌入石墨烯的樣品製作方法，實驗儀器以及量測方式。透過一系列的變溫，掃場量測，藉由低場的霍爾效應分析了樣品的載子濃度與遷移率，在高場的部分，我們觀察到的因朗道能級而形成的Shubnikov–de Haas (SdH)震盪，透過震幅的分析，可以量測到在氫嵌入石墨烯中的載子的等效質量和量子遷移率。同時也在震盪的相位分析中，觀察到1.3π的幾何相位和朗道能級的四重簡併，這些結果顯示我們的氫嵌入石墨烯樣品大部份是單層結構，其良好的特性也可作為未來更進一步的研究與應用所需的材料及參考。

關鍵字

石墨烯 ； 朗道能級 ； 幾何相位

並列摘要

As a promising material to extend the Moore’s law, graphene has been studied extensively in recent years. Among these research topics, devices grown on epitaxial silicon carbide (SiC), have received considerable attention due to its capability of high quality and large scale growth. In this thesis, the electron-magneto transport properties of hydrogen-intercalated epitaxial graphene grown on SiC have been investigated. We first introduce the background knowledge of graphene’s band structure and carrier transport properties, followed by the detailed description of our growth method and device fabrication processes using standard photolithography procedures. The magneto-electrical transport behaviors were investigated by four-terminal measurement technique at low temperature. We calculated the carrier concentration, classical mobility at the low field regime, and discussed the Shubnikov–de Haas (SdH) oscillations, coming from the Landau quantization, at high field regime. The quantum mobility and the effective mass are measured through analyzing the amplitude of quantum oscillations. The intrinsic Berry phase, which equals to 1.3π, and the four-fold degeneracy, with Landau-level degeneracy equals to 4.1, were also identified in our data. The meaningful results indicate that our device is mostly consisted of a single layer graphene, and the high quality ensures its position for further applications.

並列關鍵字

graphene ； Landau quantization ； Berry phase

參考文獻

[2]Y. Zhang, Y.-W. Tan, H. L. Stormer and P. Kim, Nature 438, 201 (2005).

[23] L. Zhang, Y. Zhang, J. Camacho, M. Khodas and I. Zaliznyak, Nat. Phys. 7, 953 (2011).

[3] K. S. Novoselov, Z. Jiang, Y. Zhang, S. V. Morozov, H. L. Stormer, U. Zeitler, J. C. Maan, G. S. Boebinger, P. Kim and A. K. Geim, Science 315, 1379 (2007).

Chapter 1

[1] G. E. Moore, Electronics 38, 114 (1965).