Graphene 自從2004 年首次在University of Manchester 被製備出來後隨即便成為熱門的電性傳輸研究的材料，在我們這次的實驗中我們在超高真空的環境下利用加熱SiC 使其表面Si 分解的方式去製備graphene ，在確認樣品的品質上，我們利用LEED 圖形去判斷樣品表面晶格結構的排列，並且經過分析我們可以看到樣品表面上有(6root3 x 6root3)R30 的重構。之後我們量測R-T 與霍爾效應以進一步研究graphene 在SiC 基板上電子傳輸的機制，在這個工作上我們試圖以躍遷理論去描述R-T 中所看到的曲線，並且試著利用霍爾效應的結果去計算載子濃度及霍爾遷移率，並且討論我們實驗的結果。

Graphene became a popular material as it has been prepared in University of Manchester since 2004. In our job, we heat SiC in order to decompose silicon on the Si-surface of SiC. We used LEED and AUGER technique in order to check the quality of graphene sample. First we observed the (6root3 x 6root3)R30 reconstruction on the surface of our sample and then
we found Carbon peak in AUGER spectrum. After that, we measure R-T and Hall effect by PPMS to do the further research of the electronic transport in graphene/SiC system, in this part of work we tried to analyse the R-T result by hopping theory and calculate Hall mobility and carrier concentration from Hall effect result. In the conclusion we found the active energy is totally different while the process of preparation is changed.

1 簡介1
2 儀器介紹與研究方法3
2.1 低能電子繞射( LEED ) . . . . . . . . . . . . . . . . . . . . . . 3
2.2 物理性質量測系統( PPMS ) . . . . . . . . . . . . . . . . . . . 3
2.2.1 真空控制系統. . . . . . . . . . . . . . . . . . . . . . . 4
2.2.2 溫度控制系統. . . . . . . . . . . . . . . . . . . . . . . 4
2.2.3 磁場控制系統. . . . . . . . . . . . . . . . . . . . . . . 4
2.2.4 液態氦量測系統. . . . . . . . . . . . . . . . . . . . . . 4
2.2.5 液氮隔熱系統. . . . . . . . . . . . . . . . . . . . . . . 5
2.3 四點量測(Four Point Probe Measurement) . . . . . 5
2.4 Van der Pauw 量測. . . . . . . . . . . . . . . . . . . . . . . 7
2.5 二維電子氣體( 2DEG ) . . . . . . . . . . . . . . . . . . . . . . 10
2.6 霍爾效應( Hall Effect ) . . . . . . . . . . . . . . . . . . . . . . 13
3 實驗結果的分析與討論15
3.1 低能電子繞射圖形( Low Energy Electron Diffraction Pattern) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2 電阻率隨溫度的變化. . . . . . . . . . . . . . . . . . . . . . . . 19
3.2.1 R-T 量測的實驗結果. . . . . . . . . . . . . . . . . . . 19
3.2.2 金屬性與半導體性的Fitting . . . . . . . . . . . . . . . 23
3.2.3 躍遷理論( Hopping Theory ) . . . . . . . . . . . . . . 25
3.2.4 躍遷理論的Fitting . . . . . . . . . . . . . . . . . . . . 31
3.2.5 多項式的Fitting . . . . . . . . . . . . . . . . . . . . . . 32
3.3 霍爾效應量測. . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.4 鍍上金屬電極後的樣品. . . . . . . . . . . . . . . . . . . . . . 43
3.5 Silicon Carbide 的量測. . . . . . . . . . . . . . . . . . . . . . 45
4 總結49
文獻53

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