氮化銦鎵/氮化鎵奈米線之光學特性及能隙調變之研究

Abstract

本論文主要是討論氮化銦鎵/氮化鎵奈米線的光學特性及受應力時能隙變化的情形。根據變激發功率光激螢光和時間解析光譜觀察，我們發現奈米線中並不存在應變造成的壓電場。透過模擬結果的比對，推測其應力釋放乃是透過奈米線中的缺陷態及介面擴散效應達成。經由變溫光激螢光及時間解析光譜的分析，奈米線中存在著類量子點的侷限態中心，並主導著載子複合的情況。另外，當外加應力於奈米線時，其長軸的應變量將主導能隙變化的情況。透過應變於奈米線中分佈的關係，可推得能隙變化量隨著中心到端點將呈現遞減的情況。

The optical properties and bandgap tunning of InGaN/GaN nanwires were studied. According to the power-dependent and time-resolved PL, we can not observe that the strain-induced piezoelectric field existed in nanowires. Compared with the simulation results, we suggested that the strain released through the defects and interdiffusion effect in nanowires. From temperature dependent PL and TRPL，the few quantum-like localization centers existed in nanowires and the carrier recombination process was dominated by them. Additionally, the external stress is also supplied on the nanowires and the variation of bandgap was dominated by the long-axis of nanowires. The variation of bandgap is decreasing from the center to the top of nanowires and it is also due to the strain distribution in nanowires.