楊志忠臺灣大學：光電工程學研究所林祐立Lin, Yu-LiYu-LiLin2007-11-252018-07-052007-11-252018-07-052006http://ntur.lib.ntu.edu.tw//handle/246246/50830在本研究中，我們有系統的研究不同量子井結構和厚度的氮化銦鎵/氮化鎵多重量子井光學特性及材料微結構，其中兩片樣品我們在成長五層高銦量子井之前多成長一層低銦量子井，而這五層高銦量子井的條件和控制組樣品相同，第三片樣品則是再增加量子井的厚度。從光激發螢光量測中觀察到，在底層多加入放紫光的低銦量子井的樣品中，會使得原本放綠光的量子井，頻譜紅移到橘紅光的範圍。從電激發螢光頻譜中可以看到靠近底層紫光量子井所受到的影響最大而放出橘光。應變分析結果顯示，靠近底層低銦量子井的高銦量子井，所含銦的平均含量比控制組樣品更高。銦含量增加的原因是由於低銦量子井對上層的位障層造成拉伸應變，而對接下來成長高銦量子井有更好的晶格匹配。這種效應會隨著成長更多的量子井而減小，而且對於高銦量子井，由於會有銦聚集來釋放應力，所以這種效應在高銦量子井之間並不明顯。In this research, we systematically study the optical characteristics and associated nanostructures of three InGaN/GaN multiple quantum-well (QW) samples of different QW structures. In two of the samples, a low-indium InGaN/GaN QW is grown before five high-indium ones, which are grown under the same conditions as those for growing the five QW s in another sample (the control sample). Photoluminescence (PL) measurement shows that the spectral red-shift of the QWs designated for green emission into the orange range in a light-emitting diode by adding a violet-emitting QW at the bottom. The cathodo-luminescence (CL) spectra indicate that the long-wavelength QWs close to the violet one were strongly influenced by this added QW and mainly emit the orange photons. From the calibrations of the average indium contents of those QWs based on the strain state analysis images, it is found that the QWs close to the low-indium one have higher indium contents than those in the control sample. Such an increase of indium incorporation is attributed to the pre-strain effect of the low-indium QW on the barrier layer right above it. The pre-strain effect diminishes along the growth of more QWs and is weak between the high-indium QWs, in which the formation of indium-rich clusters releases the strain.Chapter 1 Introduction…………………………………….……1 1.1 Applications of Nitride-Based Materials……………….……….……1 1.2 Growth of InGaN and InGaN/GaN Heterostructures………….….….2 1.3 Review on the Characteristics of InGaN/GaN Structures……...….…4 1.3.1 Strain Effect……………………………….………………...….4 1.3.2 Polarization and Strain-induced Piezoelectric Field….……......5 1.3.3 Spinodal Decomposition and Phase Separation……………......7 1.3.4 Indium Aggregation and Quantum Dot-like Structure…………9 1.3.5 Spontaneous Emission…………………………………….…..11 1.3.6 Band-tail Model and Temperature Dependence of Band Gap...13 1.4 Post-Growth Thermal Annealing…………………………………....15 1.5 Dependence of Optical Property On Quantum Well Width in InGaN/GaN Quantum Well Structures………………………….....17 1.6 Research Motivations and Topics………………………………...…20 Chapter 2 Sample Descriptions…………………………….…37 2.1 Sample Structures and Growth Conditions…………………………37 2.2 High-Resolution Transmission Electron Microscopy (HRTEM) …..38 2.3 X-ray Diffraction (XRD) …………………………………………...41 2.4 Electro-Luminescence (EL) ………………………………………...41 2.5 Cathodo-Luminescence (CL) ……………………………………....43 2.6 Discussions and Summary…………………………………………..44 Chapter 3 Photoluminescence (PL)………………………..…61 3.1 PL Experimental Setup…………………………………………...…61 3.2 PL Measurements Results………………………………………...…62 3.3 Discussions and Summary……………………………………….…65 Chapter 4 Time-Resolved Photoluminescence (TRPL)…….…77 4.1 TRPL Experimental Setup…………………………………………..77 4.2 TRPL Measurements Results ……………………...…………….…78 4.3 Discussions and Summary………………………….……….………82 Chapter 5 Conclusions………………………………....…….1011848743 bytesapplication/pdfen-US預施應力氮化銦鎵氮化鎵量子井光學OpticalPre-strainedstrainedInGaNGaNQuantum Wellsthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50830/1/ntu-95-R93941038-1.pdf