本論文主要研究在氮化鎵發光二極體上成長奈米金屬粒子，使量子井(Quantum well)與表面電漿子(Surface Plasmon)耦合，提升元件內部量子效率，觀察在光激發與電激發下的光電特性，並提出一種特殊的氮化鎵發光二極體結構，稱為擴散輔助(Diffusion-Assisted)發光二極體，該結構的量子井位於元件的表層，以載子擴散的機制使注入的載子擴散至主動層中，達到載子複合放光的目的，透過能帶模擬的方式闡明該載子注入機制的可行性，並實際製作元件進行光電特性量測，最後也將侷域性表面電漿共振(Localized Surface Plasmon Resonance, LSPR)結合典型p-i-n氮化鎵發光二極體元件之中，觀察並討論該元件的光電特性。

本實驗利用電子束蒸鍍機(E-beam Evaporator)在氮化鎵發光二極磊晶片上蒸鍍不同厚度的銀金屬薄膜，並以不同的退火條件，來實現低成本且製程簡易的奈米銀粒子，利用光激螢光(Photoluminescence, PL)光譜量測觀察到加上奈米銀粒子後的相對光強度明顯的提升，並透過時間解析光激螢光量測(Time-resolved photoluminescence, TRPL)觀察載子的生命週期，加上奈米銀粒子後載子生命週期明顯的變短，以此證明表面電漿子與量子井之間的耦合關係。在擴散輔助發光二極體研究中，我們利用二維的能帶模擬軟體，觀察在施加外部偏壓下能帶彎曲的變化、電子於元件中的分佈情形、電洞於元件中的分佈情形、輻射複合情況，多方面的闡述此擴散機制的細節與可行性，實際製作擴散輔助發光二極體元件，在電致發光量測(Electroluminescence, EL)中並未觀察到量子井的訊號峰，僅觀察到氮化鎵的材料訊號，推測p型氮化鎵濃度過低，使電流路徑直接經最短路徑傳遞至n型氮化鎵的電極處，使大多數的載子皆於氮化鎵的p - n接面中複合。最後我們將典型的p-i-n氮化鎵發光二極體蝕刻至多重量子井裸露於元件表層，並在該區域製作奈米銀粒子，在電致發光光譜中可以觀察到相對光強度有略為的提升，該光強度提升幅度不如預期，可歸因於表層奈米銀粒子造成遮光影響了整體光強度的提升，及侷域性表面電漿共振穿透深度僅能與3至4對量子井耦合，對於整體光強度的提升效果有限，以及該元件電流散佈較差造成的結果。

In this study, Ag nanoparticles were grown on GaN-based light-emitting diodes wafer to enhance internal quantum efficiency (IQE) by coupling quantum well (QW) with localized surface plasmons (LSP). In the PL spectrum, the PL intensity has increased significantly. A special GaN-based LED structure is proposed, called diffusion-assisted light-emitting diode. The single quantum well (SQW) of this structure is located at the surface of the device. The injected carriers are transported to the active layer through the carrier diffusion mechanism. The feasibility of this carrier injection mechanism is explained by the two-dimensional energy band simulation. However, because of the poor quality of the epitaxy structure, the results like electroluminescence (EL) spectrum are not as expected. Besides, we also grew Ag nanoparticles on conventional GaN-based p-i-n light-emitting diodes. In the EL spectrum, the EL intensity enhancement of the device that grows Ag nanoparticles can be observed.

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