臺灣博碩士論文加值系統

發光二極體具有節能、環保、壽命長、體積小、反應時間短等優點，而發光二極體可應用的範圍非常廣泛，在未來的固態照明市場中更被寄予厚望。藍光發光二極體主要的材料是氮化鎵(GaN)，目前，氮化合物在磊晶的過程會有很大的極化效應，極化效應會造成電子和電洞波函數重疊率降低，載子無法有效的貢獻至輻射復合、載子溢流以及載子分佈不均勻等影響，這些現象都會降低光功率輸出與發光效率。
在此論文中，吾人提出使用晶格匹配之四元 AlInGaN 量子井結構與傳統的結構做相比，並比較載子於各量子井的分佈以及輻射復合( radiative recombination )、蕭克利-里德-霍爾復合(Shockley-Read-Hall, SRH) recombination與歐傑復合( Auger recombination )三種載子復合機制，最後說明這些現象如何影響光輸出功率。此論文的第一章內容介紹發光二極體的發展與其應用及影響三族氮化合物發光二極體發展的問題，第二章以漂移-擴散模型來描述載子傳輸的行為，以量子力學模型來解釋載子復合的機制，接著第三章介紹氮化物材料特性與模擬參數設定及元件結構的設計，在第四章分析模擬的結果，結果證實此文提出的結構，能使主動區的載子重疊率增加，使載子復合的機會大為提升，以及降低SRH與Auger 非輻射復合率，在高操作電流下，可改善效率下墜現象，故光功率輸出也隨之提升，因此並獲得更好的發光強度。並接著探討厚度與層數對元件的影響性。

Since the advantages of light-emitting diodes (LEDs) in the market of solid-state lighting, such as low power consumption, long lifetime and compact size, the properties of LEDs have been widely studied, particularly, the III-nitride light-emitting diodes (LEDs) according to their wide emission spectra. The gallium nitride (GaN) is the major material for blue light LED. However, the stress in the hetero-structures made from nitride compound usually induces strong spontaneous and piezoelectric polarizations, which lead to carrier leakage, non-uniform carrier distribution, and, thus, to result in the degradation of output light power or internal quantum efficiency.
In this thesis, the new structures of LEDs with lattice-matched quaternary alloy InGaN/AlGaInN multiple quantum-wells are proposed to enhance the output power in comparison with the traditional structure. The simulation model considers the effects of the Shockley-Read-Hall (SRH), radiative and Auger recombination. Chapter 1 gives a brief introduction to the development of blue light LED and its applications. Chapter 2 presents the transport theory based on the drift-diffusion and quantum mechanics models. Chapter 3 presents the proposed structures and parameter settings in the simulation software APSYS. The results and discussions are given in Chapter 4. Finally, a conclusion is given in Chapter 5.

摘要 I
ABSTRACT III
誌謝 V
目錄 VI
圖目錄 VIII
表目錄 X
第一章 緒論 1
1-1 發光二極體發展介紹 1
1-2 III-Nitride系列發光二極體 5
第二章 模擬理論 7
2-1 能帶結構 7
2-2 漂移-擴散模型 11
2-3 載子復合機制 12
2-3-1 輻射復合 12
2-3-2 蕭克利-里德-霍爾復合 18
2-3-3 歐傑復合 20
第三章 模擬結構與參數設定 22
3-1 Ⅲ-Nitride化合物材料特性 22
3-1-1 應力形變 23
3-1-2 極化效應 25
3-2 元件結構設計 26
3-2-1 能隙與晶格常數計算 28
3-2-2 元件參數設定 33
第四章 結果討論與分析 36
4-1 不同AlxbInybGaN井障之元件特性模擬 36
4-2 不同厚度的量子井與井障變化之影響 50
4-3 量子井層數變化之影響 55
第五章 結論 59
參考文獻 60

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