本文主要是研究在AlxGa1-xN/GaN異質結構材料下中的二維電子氣(Two-Dimensional Electron Gas)在低溫高磁場下一些傳導性質的研究。我們使用Shubnickove-de Hass (SdH)來量測對於不同線寬下，GaN的電子特性。首先我們先對於樣品，在300 K及77 K做基本Ven der Pauw Hall量測，再經過核心設施ㄧ連串的曝光顯影蝕刻，做成線寬從50 nm~900 nm不等的Hall Bar型式。接著我們分別對樣品作不同溫度下的SdH量測，最後再加以照光，探討不同照光時間下，對於樣品載子濃度的變化。由本次實驗結果可知，80 nm、100 nm與900 nm為正持續光導(PPC)，其他樣品載子濃度隨著照光時間增加似乎沒有明顯增加或減少趨勢，所以無法判斷為正負持續光導。

We measured the electronic properties of Two Dimensional Electron Gas in AlxGa1-xN/GaN （x=0.18）heterostructures at low temperature and high magnetic field by Shubnikov-de Hass(SdH) for different width. First, we measurement the electronic properties by Ven der Pauw at 300 K and 77 K. For the series sample，we found that 80 nm,100 nm,900 nm sample have PPC (positive persistent photoconductivity effect) properties. The other samples did not change carrier concentration obviously for long illumination time.

摘要………………………………………………………………….. 1

Abstract…………………………………………………………….. 2


第一章 簡介


1-1 前言……………………………………………………….. 3


1-2 實驗基本設備……………………………………………… 7


第二章 理論部份

2-1 　前言.............................................. 8

2-2 Landau level 和spin splitting Landau level.........10

2-3 Shubnikov-de Haas 效應............................ 11

2-4 正持續光導效應(PPC)及負持續光導效應(NPPC)......... 14

2-5 霍爾效應(Hall Effect)............................ 16





第三章 實驗儀器與步驟

3-1 霍爾實驗.......................................... 18

3-2 Labview 程式.......................................28




第四章 實驗結果分析與討論

4-1 實驗樣品.......................................... 34

4-2 實驗結果.......................................... 36

第五章 實驗討論與結論................................... 79



References............................................... 83

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