實驗中我們使用光調製反射光譜(photoreflectance)和非接觸式電調製反射光譜(Contactles Electroreflectance)在溫度288 K下量測c-平面n-type doping ZnO的譜線，發現在光調製反射光譜和非接觸式電調製反射光譜中，Zn面的譜線相位相同、O面的譜線相位相反，這表示 Zn及O面的表面電場方向相反，因為氧化鋅在C軸上有極化電場，其方向是由O面指向Zn面，除了極化電場還存在空乏電場，空乏電場不論是Zn面或者O面其方向都是朝外，若載子濃度n≦1017(1/cm3)，極化電場強度強過空乏電場，因此Zn面的電場是朝外而O面的電場是朝內，且Zn面電場的強度大於O面的。而後我們在非接觸式電調製反射光譜實驗過程中，添加了汞燈的變數，再利用勞倫茲的公式，使用三個能量A、B、C(即三個分裂能階)去做擬合，比較其擬合後的分裂能階偏移量；當樣品照射到汞燈後，其內建電場會衰減，我們的非接觸式電調製反射光譜中，加入汞燈光照的譜線有向高能量偏移(藍移)的傾向，且Zn面的偏移量大過O面的偏移量，我們可以知道氧化鋅的躍遷機制。

Photo reflectance（PR） and Contactless electroreflectance（CER）spectra of Zn and O-faces of a c-plane ZnO bulk have been measured at room temperature, respectively. It was found that the phase of PR is the same as that of CER for the Zn-face and they are inverted for the O-face. This indicates a polarization induced field existing in the c- plane ZnO bulk due to nonzero spontaneous polarization. In addition, a mercury lamp was focused on the ZnO sample in the CER measurements to provide a photovoltaic voltage to reduce electric field in the sample. The CER spectrum with Hg lamp is more blue-shifted and its amplitude is smaller than that without Hg lamp. Hence, the type of transitions was classified as excitonic transition. The A, B, and C excitonic transition energies were obtained by fitting experimental spectra.

第一章 序論 1
第二章 半導體能帶理論 2
2.1能帶理論 2
2.2直接能隙與間接能隙 3
2.3激子 4
2.4空乏電場 4
2.5光電壓效應 6
第三章 調製光譜學 8
3.1調製光譜學簡介 8
3.2調製光譜與介電函數關係 8
3.3電子躍遷性質 9
3.4利用電子躍遷性質導出介電函數 11
3.5調製光譜學-低電場調製 14
第四章 樣品特性 17
4.1水熱法簡介 17
4.2氧化鋅(ZnO)樣品簡介 17
4.3氧化鋅(ZnO)光學特性 19
4.4氧化鋅(ZnO)能帶特性 19
第五章 實驗設置 22
5.1 PR實驗 22
5.2 CER實驗 23
5.3 CER實驗加上汞燈照射 23
5.4 相位分析 25
5.5 調製訊號分析 27
5.6 光感應電流理論 29
第六章 實驗結果 32
6.1 PR&CER光譜圖形比較 32
6.2 CER光譜圖形分析 33
6.3 CER光譜圖形擬合(fit) 35
6.4 偏移量理論計算Zn面 38
6.5 偏移量理論計算O面 40
6.6 偏移量理論計算Zn & O面 41
第七章 結論 42
參考資料 43

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