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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/94368

    Title: 新型圖樣化基板應用於氮化鎵發光二極體效率提升之研究
    Other Titles: Study of the novel patterned sapphire substrate applied for enhancing the efficiency of the GaN-based light-emitting diodes
    Authors: 羅瑛蕙;Lo, Ying-Hui
    Contributors: 淡江大學化學工程與材料工程學系碩士班
    許世杰;Hsu, Shih-Chieh
    Keywords: 發光二極體;圖樣化藍寶石基板;漸變折射層;氮化矽;光萃取效率;Light-Emitting Diode;Patterned Sapphire Substrate;Reflective Index-gradient;Silicon Nitride;Light Extraction Efficiency
    Date: 2013
    Issue Date: 2014-01-23 14:29:00 (UTC+8)
    Abstract: 本實驗乃利用Si3N4來取代SiO2作為漸變折射層材料(Reflective Index-gradient Material)並結合圖樣化藍寶石基板(Patterned Sapphire Substrate, PSS)技術來製備新型圖樣化基板應用於氮化鎵發光二極體(GaN-based LED)作效率提升之探討。此技術主要是藉由氮化鎵的水平式成長來降低缺陷密度並以漸變折射層及圖樣化基板來提升光萃取效率。從模擬結果可得知,相較於PSS-LED,使用了Si3N4作為漸變折射層的發光二極體其光萃取效率約提升62.7%。由TEM圖可觀察到貫穿差排(Threading Dislocation)出現於基板溝渠處,而圖樣化基板上方則因為水平式磊晶生成了疊層缺陷(Stacking Fault)以及磊晶縫合時所形成的單一貫穿差排,實驗結果也證實了氮化鎵確實是以水平式的方式作磊晶。
    此外,經由實驗發現因為Si3N4粗糙表面導致氮化鎵經水平式成長後於氮化鎵與圖樣化基板間存在著氣體孔洞,根據模擬結果發現氣體孔洞的存在會影響到元件的發光效率。分別以Snell’s Law以及不同點光源的位置作分析可獲得四個不同結構之發光二極體其光萃取效率大小分別為PSN-LED > PSA-LED > PSO-LED > PSS-LED。
    We use silicon nitride (Si3N4) to replace silicon dioxide (SiO2) as the reflective index-gradient material to fabricate GaN-based patterned sapphire substrate light-emitting diodes. It can not only reduce the threading dislocations densities but also enhance the light extraction efficiency (LEE). From the simulation results, the light extraction efficiency enhance approximate 62.7% higher than the PSS-LED. The TEM images show the threading dislocations exist on the trench region and stacking faults produce on the top of the pattern because of the GaN growth laterally. And also we found one threading dislocation which induced from coalescence of GaN thin film on the pattern region only. These evidences prove that the GaN film indeed was grown laterally.
    After re-growing, we observed the air voids exist on the top of the textured Si3N4 layer which were due to the GaN epitaxial lateral overgrowth. According to the simulation result, it reveals that the air voids will affect the final luminous efficiency. The luminous efficiency ranking of the four different LEDs is PSN-LED > PSA-LED > PSO-LED > PSS-LED.
    Appears in Collections:[化學工程與材料工程學系暨研究所] 學位論文

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