| Summary: | 碩士 === 國立中央大學 === 機械工程學系 === 104 === 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.
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