半極化面{10-11}氮化銦鎵/氮化鎵奈米金字塔發光二極體之製作及特性研究

Abstract

在本論文中，我們介紹高性能綠光發光二極體用選區成長技術將半極化面{10-11}氮化鎵奈米金字塔成長於藍寶石基板上。 從穿透式電子顯微鏡(transmission electron microscopy, TEM)影像 中發現選區成長技術可以減少半極化面{10-11}多重量子阱內的穿透錯位密度。而且，從變功率光激發螢光(Photoluminescence, PL)量測可以看出半極化面多重量子阱的內建電場較小、內部量子效率較高。另外，時間解析光激發螢光(Time resolved Photoluminescence, TRPL)量測顯示半極化面{10-11}多重量子阱的輻射複合時間遠小於極化面(0001)多重量子阱。這些分析結果可以歸納出因為使用半極化面{10-11}多重量子阱而確實能夠減緩量子阱中的量子侷限史塔克效應(Quantum confined Stark effect, QCSE)。 最後，我們將做成元件的綠光、黃綠光、橘光發光二極體用電激發螢光(Electroluminescence, EL)量測分析出L-I-V曲線。此外，我們用空間解析陰極射線激發螢光(Cathodoluminescence, CL)量測做變電流大小電激發螢光(Electroluminescence, EL)量測的光譜分析討論。

In this study, we presented high performance green emission semipolar {10-11} GaN-based nanopyramid light emitting diodes (LEDs) grown on c-plane sapphire substrate by selective area epitaxy (SAE). The transmission electron microscopy (TEM) images suggest that the SAE can suppress the threading dislocation density in the semipolar {10-11} multiple quantum well (MQWs). Besides, from power dependent PL measurement, the internal electric field (IEF) of semipolar MQWs was reduced, and the internal quantum efficiency (IQE) was improved. Moreover, time-resolved PL (TRPL) measurement shows the radiative recombination lifetime of semipolar MQWs was shorter than that of c-plane MQWs. These results could strongly confirm the reduction of quantum confined Stark effect (QCSE) by using semipolar MQWs. Finally, the L-I-V curves of green, olivine and orange emission nanopyramid LEDs were investigated by electroluminescence (EL) measurement. And the EL peak shift and emission behavior could be referred to the spatial distribution of nanopyramid, which was investigated by by cathodoluminescence (CL) measurement.