詹國禎臺灣大學：光電工程學研究所吳家穩Wu, Chia-WenChia-WenWu2007-11-252018-07-052007-11-252018-07-052004http://ntur.lib.ntu.edu.tw//handle/246246/50722本論文利用溫變的光致螢光光譜術(photoluminescence)、光調制反射率光譜術(photoreflectance)和光激發的溫度和必v變化的實驗來研究分子束磊晶成長(MBE)的砷化銦(InAs)自我組成量子點的光激發的光學性質。以掃描式電子顯微術(scanning electron microscopy;SEM)和原子力顯微鏡(atomic force microscopy:AFM)來觀測量子點的密度和尺寸大小。樣品中，多了一層砷化銦鎵的緩衝層(buffer layer)會使得量子點的密度增加，也降低了量子點的平均大小。螢光光譜術的實驗中，使用高斯函數吻合，吻合的特徵來自於量子點的光學躍遷(optical transition)，並且可以與光調制光譜術的實驗吻合資料相互做個對應。我們觀察並討論到不尋常且特殊的線寬隨溫度縮窄和光致螢光光譜術的強度隨溫度增強現象。我們認為這種強度增強的現象是由溼層(wetting layer)引起的載子儲存效應所造成的。我們提出載子分佈速率方程式(rate equations)的模型來模擬這一個不規則的溫度變化現象。The optical properties are researched with temperature dependent photoluminescence (PL) and photoreflectance (PR) and power dependent experiments on MBE grown InAs self-assembled quantum dots. The density and size uniformity of quantum dots was measured by the instrument of scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The density and average size of InAs QDs was affected by covering buffer layer of InGaAs. The experiment data was fitted by Gaussian profile in the PL experiment, and the features of the fitted result comes from optical transition of QDs, which correlated with the features observed in the PR spectra. Anomalous temperature dependence of PL in broadening parameter and integrated intensity is also discussed. We attributed the enhancement of PL intensity signal to be carrier releasing from potential fluctuation in the wetting layer (WL). The model of the rate equations was proposed and simulated.Contents 摘要 I Abstract II Contents III List of Figures V List of Tables VI Chapter Ⅰ Introduction 1 Chapter Ⅱ Theoretical background 4 2-1 Optical properties in semiconductors 4 2-2 Modulation spectroscopy 8 2-2-1 Advantages of modulation spectroscopy 8 2-2-2 Critical points 10 2-2-3 Lineshape considerations 11 2-2-4 Third derivative spectroscopy (low-field regime) 12 2-2-5 First derivative spectroscopy 13 2-3 Rate equation model 16 Chapter Ⅲ Material and method 18 3-1 Sample preparation 18 3-2 Photoluminescence system 21 3-3 Photoreflectance system 23 Chapter Ⅳ Results and discussion 25 4-1 Transition energy 25 4-1-1 Photoluminescence 25 4-1-2 Photoreflectance 30 4-1-3 Atomic force microscopy 34 4-2 Broadening parameter 37 4-3 Anomalous temperature behavior 40 Chapter Ⅴ Conclusions 44 Appendix 45 References 47740226 bytesapplication/pdfen-US光反射率調制光譜術分子束磊晶成長術原子力顯微鏡電子式掃描顯微鏡光激發螢光光譜術PhotoluminescencePhotoreflectancemolecular beamthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50722/1/ntu-93-R91941006-1.pdf