https://scholars.lib.ntu.edu.tw/handle/123456789/173369
標題: | 不同矽摻雜條件之氮化銦鎵/氮化鎵多重量子
井奈米結構之穿透式電子顯微術分析研究 Transmission Electron Microscopy Studies of InGaN/GaN Multiple Quantum Well Nano-Structures of Different Silicon Doping Conditions |
作者: | 陳孟谷 Chen, Meng-Ku |
關鍵字: | 量子井;氮化銦鎵;氮化鎵;quantum well;GaN;InGaN | 公開日期: | 2004 | 摘要: | 在本研究中,我們探討了在不同條件下氮化銦鎵/氮化鎵多重量 子井的奈米結構,包括不同銦原子濃度、不同矽摻雜區域與不同矽摻 雜濃度等條件。我們也研究了熱退火與電子束照射對奈米結構所造成 的效應。研究樣品的方法包括材料與光學分析,材料分析的方法包括 有高解析度穿透式電子顯微術與應變分析,光學分析的方法包括有激 發螢光光譜與激發螢光吸收光譜。在應變分析中,我們可以清楚地觀 察到在不同摻雜條件下其奈米結構的變化。一般而言,在矽摻雜的樣 品中會形成較多的銦聚集結構,尤其是摻雜在位障層中的樣品更明 顯。而且銦聚集的現象也會隨著矽摻雜濃度增加趨於明顯。光學的測 量也證實矽摻雜的確可以改善載子的結合效率。從這樣的量測結果可 歸因於在矽摻雜的樣品中有較強的載子侷限和應力的釋放。我們也觀 察到熱退火可以改變其奈米結構及其光學特性。最後,我們也發現量 子井在幾分鐘以內的電子束照射下並不會明顯改變其奈米結構。 In this research, we have investigated the nanostructures of InGaN/GaN multiple quantum wells (MQWs) with different indium concentrations, different silicon doping regions, and different silicon doping concentrations. We also studied the effects of post-growth thermal annealing and electron beam exposure on the nanostructure. The methods used for studying our samples, including material and optical analysis methods. Material analysis methods include high-resolution transmission electron microscopy (HRTEM) and the strain-state analysis (SSA). Optical analysis methods include photoluminescence (PL) and photoluminescence excitation (PLE). From strain-state analysis (SSA) results, we could clearly see the differences of nanostructures between the samples of different doping conditions. Typically, more clusters were formed in Si-doped samples, particularly in the barrier-doped sample. Also, more clusters can be formed by increasing silicon doping concentration. Optical measurements showed that with Si-doping, the recombination efficiency could be improved. Such an improvement could be attributed to stronger carrier localization (more clusters formed) and better strain relaxation (weaker quantum-confined stark effect) upon silicon doping, particularly doping in barriers. We have observed that thermal annealing could change the nanostructures and optical properties of InGaN/GaN MQWs. We have found that electron beam exposure for a few minutes may not change the nano-structure of an InGaN/GaN QW sample. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/57236 | 其他識別: | en-US |
顯示於: | 電子工程學研究所 |
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ntu-93-R91943101-1.pdf | 23.31 kB | Adobe PDF | 檢視/開啟 |
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