本論文主要探討將空隙(Air Gap)陣列置入未摻雜氮化鎵(u-GaN)並結合圖案化藍寶石基板(PSS)LED之光電特性，期望可以藉由Air Gap與u-GaN折射率的不同，增加光在內部散射機率，進而提升光輸出功率。

實驗方面利用磊晶側向成長(ELOG)技術將Air Gap陣列置入Conventional LED 及PSS LED，並且分析了Conventional LED、Air Gap in Conventional LED、PSS LED及Air Gap in PSS LED四種試片。於電流20mA注入下，順向導通偏壓分別為3.40V、3.41V、3.45V及3.46V，相較於Conventional LED增加0.01~0.06V；而光輸出功率分別為3.06mW、3.99mW、4.72mW與5.29mW，相較於Conventional LED明顯提升了0.93~2.23mW，約增加30.39~72.88%。

此外，我們得到內部量子效率(IQE)及光萃取效率(LEE)，發現Air Gap in PSS LED有較高的IQE，這是因為Air Gap in PSS LED具有高品質的磊晶薄膜。最後利用Trace Pro光學模擬軟體驗證實驗所量測之LEE。

In this study, we discussed optoelectronic characteristics of GaN-based light emitting diodes (LEDs) with combined air gap array and patterned sapphire substrate (PSS). We expected to increase the light scattering by the refractive index difference between air gap and GaN could enhance guided-light scattering efficiency.

In this experiment, we inserted air gap array in conventional and PSS LEDs by epitaxial lateral overgrowth (ELOG) technology and analyzed optoelectronic characteristics of conventional LED, air gap in conventional LED, PSS LED, and air gap in PSS LED. Under 20-mA current injections, the forward voltage were 3.40, 3.41, 3.45, and 3.46 V for conventional LED, air gap in conventional LED, PSS LED, and air gap in PSS LED, respectively. The 20-mA of light output power of conventional LED, air gap in conventional LED, PSS LED, and air gap in PSS LED were 3.06, 3.99, 4.72, and 5.29 mW, respectively.

Furthermore, we obtained the internal quantum efficiency (IQE) and light extraction efficiency (LEE). The air gap in PSS LED exhibited larger IQE contrast to other LEDs because of the improved quality of lateral growth-induced crystal. Finally, we verified the LEE between the result of experiment and simulation by Trace Pro optical simulation software.

第一章
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