發光二極體效率降低的數值研究;Numerical Investigation of Effciency Droop in Light-Emitting Diodes

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/72409

Title:	發光二極體效率降低的數值研究;Numerical Investigation of Effciency Droop in Light-Emitting Diodes
Authors:	吳輝昕;Thinh,Vo Huy
Contributors:	機械工程學系
Keywords:	效率降低;發光二極體;Effciency Droop;Light Emitting-Diodes
Date:	2016-07-26
Issue Date:	2016-10-13 14:53:06 (UTC+8)
Publisher:	國立中央大學
Abstract:	由於氮化鎵之發光二極體（LED）具備高效率和環境友善，長期以來均被認為是未來照明技術的主要光源。然而，氮化鎵LED於照明應用最顯著的挑戰之一，是高功率操作時之效率降低。在這項研究中，我們使用數值方法配合ABC模型來分析LED的效率下垂。首先COMSOL多重物理軟體之有限元法（FEM），被使用來模擬氮化鎵LED之電和熱的問題通。隨後，為了達到對複合係數有更好的預測精度值，使用TracePro軟體來模擬光學行為，並考慮光吸收的效應。經由考慮電光熱，數值模擬結果有良好的精確度，與實驗結果一致。另外，光輸出功率顯示出光學效果對複合係數的影響。它證明了複合係數的精確度與光輸出功率的關係。此外，亦可觀察到載體的特性和LED的效率之關聯性。經由數值模擬之結果，可發現引起氮化鎵LED效率下垂主要的原因，為載子溢出，而遮光效果會增加光能量吸收，造成輸出光之損耗，為LED光萃取效率下垂的主要原因。 ;GaN-based light-emitting diodes (LEDs) has long been considered as potential light source for the future due to their high energy efficiency and environment friendly lighting technology. However, one of the most significant challenges facing to LEDs is the efficiency droop which is the efficiency degradation with increasing power operation. In this study, we present a numerical method to analyze the efficiency droop on LEDs based on the modified ABC model. The electrical and thermal problem first are solved by the finite element method (FEM) by ComSol Multiphysics Software. Afterward, in order to achieve a better accuracy value for the recombination coefficient, optical absorption will be considered and solved by using TracePro software. By considering the optical effect with electrical thermal problem, the result is carried out which shows a good accuracy compared to the experimental result. Moreover, the light output power shows the difference by considering the optical effect on the recombination coefficient. It proves that the accuracy of the recombination coefficient will be associated directly on the light output power. Besides, the carrier characteristic as well as LED’s efficiency also can be observed. Through the simulation result, the main reason causes the droop in efficiency of GaN based LEDs which is carrier overflow while the shading effect will increase the absorption energy causes the loss in light output power which is supposed to be the main reason for the droop in light extraction efficiency of LEDs.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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