摘要 本研究主要在探討如何利用二維光子晶體提升氮化鎵二極體發光效率。論文中描述提升發光效率機制有二個：一為利用表面週期性結構造成布拉格散射，以減少全內反射情形發生；第二個則是利用光子晶體能隙將傳導模態導引出來，以提升外部量子效率。除此之外，當製作光子晶體時對材料的破壞會造成實際發光面積減少與非輻射複合效應增加。將此兩項效應對總發光效率的影響作討論，以及分析利用共振腔結構提升自發性輻射機率對總發光效率之影響。從上述分析結果建立一套簡易模擬模型描述光子晶體發光二極體之發光效率性質。 Abstract In this research, we study the light extraction characteristics in photonic crystal slab structures and report the enhancement results. There are two mechanisms for improved LED output power, the first is using the Bragg scattering to enhance the output efficiency by photonic crystal surface patterned and it can avoid the internal reflection probability to occur. The second mechanism is permitting the guided mode to the escape the LED slab by the photonic crystal band gap structure. Besides it, we consider the reduced emitting area and non-radiative recombination effect when photonic crystal structure inset the LED device. We also consider the resonant structure which induced the Purcell effect, and it can enhance the spontaneous emission rate. Finally, we set up a model that can describe the light characteristics in the photonic crystal LED structure.
