二元與四元位障層應用於氮化銦鎵綠光二極體之光性分析; Optical analysis of InGaN green LED by using binary and quaternary barrier

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Title:	二元與四元位障層應用於氮化銦鎵綠光二極體之光性分析;Optical analysis of InGaN green LED by using binary and quaternary barrier
Authors:	李政鴻;Zheng-Hong Lee
Contributors:	電機工程研究所
Keywords:	氮化鋁銦鎵;量子井;氮化銦鎵;綠光二極體;AlInGaN;green LED;quantum well;phase separation;InGaN
Date:	2002-06-19
Issue Date:	2009-09-22 11:45:35 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本論文是利用氮化合物半導體系列的材料作為綠光發光二極體，且吾人認為活性層氮化銦鎵(InGaN)的相分離(phase separation)情形，是提高量子效率重要的因素，故在本研究中是利用磊晶的條件與材料來促使形成。本論文可分為三部份第一是元件的製作過程；第二是利用成長氮化鎵(GaN)位障層時溫度的變化，來討論活性層(InGaN)的相分離狀況；第三則是改變位障層材料為氮化鋁銦鎵(AlInGaN)，經由活性層所受應力的改變來觀察相分離情形。在量測方面分別以變溫光子激發光量測(Photoluminescence , PL)與變電流電子激發光量測(Electroluminescence , EL) 以及光強度量測(box car L-I)，從以上光的分析定義其相分離影響發光機制的差異，並探討相分離在光強度上的貢獻。最後吾人發現其活性層相分離的情形，是跟應力的釋放有關，故氮化鋁銦鎵位障層之試片展現出明顯的相分離，而在光亮度的表現上也是以相分離較明顯之試片為最佳。 In this thesis, InGaN/GaN and InGaN/AlInGaN multiple quantum well (MQW) light emitting diode were grown by low pressure metal-organic chemical vapor deposition(MOCVD). There are two versions of the emission mechanism in multiple quantum well. One is dominated by quantum well state, the other is dominated by localized state due to the In-rich regions in quantum well. Because the long wavelength InGaN LEDs have to increase the composition of indium in InGaN layer, they form the In-rich regions, so called phase separation ,easily in InGaN layer. In the past study of the In-rich regions, they have found that the formation of In-rich regios in the InGaN layer could be radiative centers for recombination of carriers, and improved the internal quantum efficiency in the multiple quantum well. Therefore, we will enhance the formation of In-rich regions in the InGaN layer by changing growth condition and material in this thesis. Firstly, we vary the growth temperature of barrier(GaN) to lead to congregate of indium in InGaN layer. But they are not evident that the emission mechanism is influenced with the In-rich regions from photoluminescence and electroluminescence measurement . So, it is difficult to enhance the In-rich regions by the growth temperature of barrier. Because the congregate of indium is formed due to strain release in InGaN layer, we make it in the InGaN layer easily by using the AlInGaN barrier instead of the GaN barrier. From photoluminescence and electroluminescence measurement, the In-rich regions in the InGaN layer are really clear by using the AlInGaN barrier instead of the GaN barrier. Moreover, the optical intensity of LED with AlInGaN barrier is stronger than that of LED with GaN barrier. For the long wavelength LED, it is important to form the formation of In-rich regions in the InGaN laye
Appears in Collections:	[Graduate Institute of Electrical Engineering] Electronic Thesis & Dissertation

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