本論文以有限時域差分法(FDTD)建立一個三維的理論計算模型，研究發光二極體結構的改善對光亮度提升的影響，主要討論的結構為表面成長多孔性陽極氧化鋁的AlGaInP發光二極體，以及底層蝕刻週期性柱狀結構的圖案化基材GaN發光二極體。透過以傳統結構LED計算出的光亮度做規一化，可評估結構的改善對光亮度提升的量值，用以分別討論多孔性陽極氧化鋁以及底層柱狀結構參數變化的影響。
經由理論計算的結果，AlGaInP發光二極體可藉由多孔性陽極氧化鋁薄膜得到約35%的光亮度提升，另一方面，GaN發光二極體圖案化基材的底層柱狀結構，也對光亮度提升有30%的增強效果。這些結構對光亮度的作用，可藉由光學行為上相互影響的物理機制加以解釋，此外，為了對照理論計算的結果，多孔性陽極氧化鋁及底層柱狀結構的發光二極體都加以實作，而實驗的結果也表現出與理論計算一致的趨勢。

A three-dimensional model with finite-difference and time-domain (FDTD) method was established to investigate the enhancement of the light output intensity in improved light-emitting diodes (LEDs) structure. There are two major structures considered in this thesis. One is the AlGaInP LEDs with porous anodic alumina (PAA) film deposited on top surface, and the other is GaN LEDs with bottom pillar (BP) patterned substrate. Through comparing the calculated normalized light extraction intensity from conventional LEDs, AlGaInP LEDs with PAA film and GaN LEDs with BP structure in different dimensions were studied respectively.
From the theoretical result, it shows that the light output intensity in the AlGaInP LEDs with PAA film involved could be enhanced by about 35%. On the other hand, an improvement of the GaN LED with BP patterned substrate could be obtained by about 30%. The influence of these two structures on the light output intensity of LEDs could be explained by the physic model of light interaction. In addition, the practical fabrications of porous anodic alumina film and bottom pillar were both carried out. The experimental results of PAA and BP structures also show the same trend to the theoretical calculations.

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