非極性a面氮化鎵缺陷型光子晶體共振腔特性之研究

Abstract

在本篇論文中，我們成功製作出高效率高品質因子a面氮化鎵缺陷型光子晶體共振腔，並研究其光學特性。傳統成長在c面的氮化鎵量子井因為存在著量子侷限效應，使得量子井的復合效率降低。為了改善量子侷限效應的影響，我們將使用a面氮化鎵量子井來改善此問題，並設計薄膜結構的缺陷型光子晶體，使用電子束微影以及聚焦離子束製作出高效率高品質因子的共振腔，並且比較與分析製作在傳統c面以及a面之氮化鎵缺陷型光子晶體共振腔的差異。 低溫77K下，針對a面缺陷型光子晶體共振腔量測光激螢光頻譜，觀察到單一模態出現在419.3nm，其品質因子高達2×10^3以及極化率為51.3%，相較於c面缺陷型光子晶體的極化率高了8%。並在發現隨著注入載子的增加，共振模態的波長沒有藍移的現象。證實了在a面氮化鎵上製作光子晶體，大幅降低量子侷限效應的影響。

In this thesis, the high efficiency and high quality factor a-plane GaN-based photonic crystal (PC) L7 defect cavities were demonstrated and analyzed. The conventional c-plane quantum wells suffered from quantum confined Stark effect (QCSE), decreasing the recombination efficiency of the quantum wells. In order to solve this issue of QCSE, nonpolar a-plane GaN-based PC L7 defect cavities were proposed and fabricated using e-beam lithography and focused-ion beam milling. The optical characteristics of GaN-based PC L7 defect cavities on conventional c-plane and a-plane were compared and discussed. The a-plane and c-plane PC L7 defect cavities were measured using micro-photoluminescence at 77K. One dominated resonant mode was observed at 419.3nm with a quality factor of 2×10^3 in the a-plane PC L7 defect cavities. The degree of polarization of the a-plane PC L7 defect cavities was estimated to be 51.3%, which was 8% higher than that of the c-plane device. The resonant mode was almost invariant with increasing the injection carriers in a-plane PC L7 defect cavities, indicating that the a-plane PC L7 defect cavities are free of quantum confined Stark effect.