金屬反射層對發光二極體發光強度增強及光型調製之研究

Enhancement of Lumination and on Modification of Light Pattern of InGaN Light-emitting Diodes by Metallic Reflector

顏嘉緯(Jia-Wei Yan)

指導教授 ： 陳啟昌 ； 李建階

國立中央大學/理學院/光電科學研究所/碩士(2008年)

摘要

本論文主要是研究表面電漿效應增加氮化銦鎵發光二極體(LED)的發光強度及修正光型的效果，以及探討在發光層與金屬反射層介面間的透明導電層銦錫氧化物(indium tin oxide；ITO)對介面有效折射率之調製，以提昇表面電漿之耦合效率。在實驗上，先經由發光元件表面上金屬薄膜(t=15~100nm)、及金屬奈微米週期結構(p=0.2~8?m)反射層的設計與製作。然後利用光激發螢光(photoluminescence，PL)及角度解析光激發螢光(Angle-Resolved photoluminescence，ARPL) 量測系統來量測其具有金屬薄膜與金屬奈微米週期結構下的發光光譜和光場分佈。分析其量測結果，當ITO(80nm)介於發光層與金屬薄膜(t=50nm)、或金屬奈微米週期結構之間時，在ITO(80nm)/Ag film(t=50nm)的樣品在發光元件總發光強度具有44.8%的發光強度提升，以及在ITO(t=80nm)/Ag grating(t=50nm, p=5μm)的樣品在發光元件總發光強度具有最佳的光強度且提升52.5%。而且此發光元件的光型隨著金屬厚度的增加有明顯集中於法線方向，具有指向性的趨勢。

關鍵字

氮化鎵 ； 表面電漿 ； 發光二極體

並列摘要

In this thesis, we study the surface plasmon effect on enhancement of lumination and on modification of light pattern of InGaN Light-emitting diodes (LEDs), and we discuss the effect of indium tin oxide (ITO) between active layer and metallic reflector on enhancing the coupling efficiency of surface plasmon. In the experiment, we design and fabricate silver film (t=15~100nm) or silver gratings with periodic structures (0.2~8?m) onto the InGaN light emitter and photoluminescence (PL) and angle-resolved photoluminescence (ARPL) techniques are used to record the spectra of different structures. We also characterize another type of reflector, inserting ITO between InGaN and Ag film or Ag gratings. From our experimental result, ITO (80nm)/Ag(50nm) film and ITO (80nm)/Ag(50nm) with grating period of 5?m exhibit significant enhancement about 44.8% and 52.5%, respectively. Furthermore, the light pattern of InGaN light emitter will converge toward the normal direction by increasing the thickness of silver.

並列關鍵字

GaN ； LED ； Surface Plasmon

參考文獻

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