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標題: | 具有不同長晶溫度之氮化銦鎵/氮化鎵多重量子井與成長在氧化鋁上之氧化鋅薄膜特性研究 Characteristics of InGaN/GaN Multiple Quantum Wells with Different Growth Temperatures and Zinc Oxide Thin Films Grown on Sapphire |
作者: | Shu-Cheng Chin 金書正 |
指導教授: | 楊志忠 |
關鍵字: | 氮化銦鎵/氮化鎵多重量子井,氧化鋅薄膜,穿透式電子顯微鏡, InGaN MQWs,ZnO,TEM, |
出版年 : | 2005 |
學位: | 碩士 |
摘要: | 本研究中,我們比較四片具有不同長晶條件的氮化銦鎵�氮化鎵多重量子井樣品的奈米結構及光學特性,其中三片具有不同的量子井層長晶溫度,我們發現在愈低溫成長之樣品中銦的平均含量愈高,同時,增幅分解的的現象也愈來愈顯著,然而,晶體結構的品質卻愈差。此外,發光波長隨著長晶溫度的降低也愈來愈長。另外一片樣品中,我們在生長位障層時通入氫氣,經由氫氣的通入,銦原子會更加的侷限在量子井層,而且可以抑制增幅分解的發生,並且由x光繞射儀的結果來看,此樣品之晶體品質是四片樣品之中最好的。在本研究的第二部份中,我們比較三片長在氧化鋁上的氧化鋅薄膜樣品,我們發現在高溫成長(450 ℃)時,薄膜結構會轉換成柱狀結構,而且經由高解析度之穿透式電子顯微鏡影像,我們發現在高溫成長的氧化鋅與氧化鋁介面層具有不同的晶體指向,從x光繞射儀可更進一步計算,氧化鋅層相對於氧化鋁層在c軸有一個三十度的旋轉角,這個三十度的旋轉角可以降低氧化鋅與氧化鋁的晶格不匹配,進而使表面能量下降。最後,我們發現,高溫成長的樣品也有比較好的發光效率。 In this research, we compare the nanostructure and optical property of four InGaN/GaN multiple quantum well samples with different growth conditions. The quantum wells of three of these samples were grown at different temperatures. The incorporated indium content becomes higher as the growth temperature decreases. The crystalline quality of a sample with a higher indium content becomes worse. Spinodal decomposition is stronger at a lower growth temperature. In addition, the photon emission wavelength is longer in a sample of a growth temperature. In growing the fourth sample, H2 flow was added to the growth chamber in growing barrier layers (undoped GaN). We find that spinodal decomposition is suppressed and indium atoms are well confined in the InGaN layers. From the X-ray diffraction (XRD) results, the crystalline quality of this sample is the best among the four samples. The second part of this research is to study the nanostructures of three ZnO thin films grown on sapphire. We observed that the ZnO thin film changes into rod-like structure at high growth temperature (450 ℃). In this sample, there is an orientation twist (30 degrees) with respect to the c-axis at the interface between ZnO and sapphire. We obtained different electron diffraction patterns between ZnO and sapphire from transmission electron microscopy (TEM) for confirming this twist. The twisted structure reduces the lattice mismatch between ZnO and sapphire, which leads to a lower surface energy. The sample of high-temperature growth has higher photon emission efficiency. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/24515 |
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顯示於系所單位: | 光電工程學研究所 |
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