楊志忠臺灣大學：光電工程學研究所姚立傑Yao, Li-ChiehLi-ChiehYao2007-11-252018-07-052007-11-252018-07-052006http://ntur.lib.ntu.edu.tw//handle/246246/50888在本研究的第一部份中，我們比較二片具有不同結構的氮化銦鎵╱氮化鎵多重量子井樣品的奈米結構及光學特性。其中一片樣品在成長和另一樣品相同的高濃度量子井結構之前，先成長一低濃度之量子井結構。我們利用穿透式電子顯微術及應力分佈分析軟體分析樣本的奈米結構。由穿透式電子顯微術所得之影像，我們可觀察到量子井間不同程度的銦原子聚集現象以及成分不均勻的變化。經由應力分佈分析計算其各個量子井的平均濃度，我們發現在和控制樣品比較下，在實驗樣本中愈接近低濃度量子井的高濃度量子井層具有較高的銦含量。這樣的銦濃度增加現象應歸因於低濃度量子井的應力對於上層的影響。同時，我們發現此種應力所造成的影響會隨者量子井層數的增加而減小。 在本研究的第二部份中，我們比較三片具有不同結構的氮化銦鎵╱氮化鎵多重量子井樣品的奈米結構及光學特性。在這三片樣品中，二種不同的量子井結構為藍光及綠光以不同的順序及數量堆疊起來。由穿透式電子顯微術所得之影像，我們可觀察各個量子井的奈米結構及其在樣品中的分佈位置。同時我們亦由應力分佈分析計算其各個量子井的平均銦濃度。我們發現量子井的濃度及在樣品中的分佈位置會對樣本之光學特性產生很大的影響。In the first part of this research, we compare the nanostructures of two InGaN/GaN multiple-quantum-well (QW) light-emitting diode (LED) samples with different structeues. In one 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 QWs in another sample. We use the techniques of High-resolution transmission electron microscopy (HRTEM) and strain state analysis (SSA) to show the material nanostructures of these two samples. From the HRTEM images, different degrees of indium aggregation and composition fluctuation between QWs are observed. From the calibrations of the average indium contents of those QWs based on the SSA 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. Also, we found that the pre-strain effect diminishes along the growth of more QWs. The second part of this research is to study the nanostructures of three InGaN/GaN multiple-QW LED samples of different structures. In these samples, QWs of two different growth conditions are stacked with different numbers and sequences. HRTEM images are obtained to show the nanostructures and distributions of the QWs in each sample. From the SSA images, we calibrate the average indium contents of the QWs. It is found that the indium contents and distributions of QWs may effect the optical properties a lot.Chapter 1 Introduction 1.1 Applications of Nitride-Based Materials/1 1.2 Group-III Nitride Materials Growth Issues/2 1.2.1 Crystal Structure of the Nitride Semiconductors/2 1.2.2 Epitaxy on Sapphire Substrates/3 1.2.3 Growth of InGaN and InGaN/GaN Heterostructures/4 1.3 Review of the Characteristics of InGaN/GaN Structures/5 1.3.1 Defects in GaN-based Materials/5 1.3.2 Strain Effect/6 1.3.3 Piezoelectric Field/7 1.3.4 Spinodal Decomposition and Phase Separation/9 1.3.5 Indium Aggregation and Quantum Dot-like Structure/12 1.4 Research Motivations/13 Chapter 2 Analysis Methods 2.1 Specimen Preparation of Cross-section TEM/37 2.2 Transmission Electron Microscopy (TEM)/40 2.3 Strain-State Analysis (SSA)/45 2.3.1 Noise Reduction by Wien Filter/45 2.3.2 Reference Lattice Method/47 2.4 X-Ray Diffraction(XRD)/50 2.5 Photoluminescence (PL/52 2.6 Cathodoluminescence (CL)/52 2.7 Electro-luminescence (EL)/53 Chapter 3 Pre-strain Effects on the emission properties of InGaN/GaN quantum-well structures 3.1 Sample Structures./.68 3.2 PL Measurements Results/69 3.3 CL Measurements Results/70 3.4 High-resolution Transmission Electron Microscopy (HRTEM) Results/71 3.5 Strain-State Analysis (SSA) Results Summary/72 3.6 XRD Results/74 3.7 Discussions/75 Chapter 4 InGaN/GaN quantum-well structures for blue/green two-wavelength emission 4.1 Sample Structures./104 4.2 PL Measurements Results/105 4.3 EL Measurements Results/106 4.4 High-resolution Transmission Electron Microscopy (HRTEM) Results/108 4.5 Strain-State Analysis (SSA) Results Summary/109 4.6 XRD Results/111 4.7 Discussions/111 Chapter 5 Conclusions/145 References/14714201944 bytesapplication/pdfen-US氮化銦鎵氮化鎵穿透式電子顯微術混合InGaNGaNTEMMixedthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50888/1/ntu-95-R93941025-1.pdf