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研究生: 童建凱
Chien-Kai Tung
論文名稱: 具氧化鋅奈米柱之發光二極體製作
Fabrication of light-emitting diode with ZnO nanorod arrays
指導教授: 楊啓榮
Yang, Chii-Rong
學位類別: 碩士
Master
系所名稱: 機電工程學系
Department of Mechatronic Engineering
論文出版年: 2010
畢業學年度: 98
語文別: 中文
論文頁數: 123
中文關鍵詞: 氧化鋅奈米線發光二極體水熱法P型氮化鎵P型氧化鋅
英文關鍵詞: ZnO nanowrie, light-emitting diode, hydrothermal method, P-GaN, P-ZnO
論文種類: 學術論文
相關次數: 點閱:265下載:33
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  • 發光二極體被視為未來主要的照明光源,高功率發光二極體於技術上屢有突破,但現階段發光效率的不足,使發光二極體無法取代傳統光源作為照明燈源的主流,故發光二極體發光效率的提升,是目前技術發展的重點之一。過去的研究指出,將奈米線應用於發光二極體的結構製作,能有效提升其發光強度;而在各式成長奈米線的方法中,水熱法製備之奈米線具有高品質順向成長與製程簡易的優點,故本論文將採用此法成長氧化鋅奈米線,並以射頻濺鍍法沉積N型氧化鋅鋁薄膜,P型材料則選用氧化鋅與氮化鎵薄膜結構,藉以製備其氧化鋅奈米線之發光二極體,並進行其發光特性之研究。
    在奈米線的部份,藉由水熱法成功製備氧化鋅奈米線,氧化鋅奈米線摻雜鋁部分,鑑於製程步驟與參數和文獻有所不同,故摻雜效果不彰,需以更多的參數進行測試。熱處理氧化鋅奈米線方面,可發現因缺陷產生的綠光波段強度明顯降低,並且對於降低阻值與能障有很大幫助。
    P型氧化鋅部份,使用摻雜P2O5氧化鋅靶材,在具有氧化鋅緩衝層之藍寶石基板上,加熱至700 C,藉由氬/氧流量比例為1:3,沉積氧化鋅磷薄膜,並在氧氣的氣氛下冷卻。隨後氧化鋅磷薄膜經由RTA處理,有可能製備出P型氧化鋅薄膜。目前在RTA持溫溫度900 C,持溫5分鐘之處理下,已製備出局部P型氧化鋅薄膜,其載子濃度為8.7921018 cm-3,移動率為0.793 cm2 / V-s,電阻率為0.8953 -cm。實驗的結果推測可能是試片電性轉換不完全所致。未來將考慮以共濺鍍或熱擴散的方式,繼續P型氧化鋅薄膜之試驗。
    發光二極體部份,目前已於P型氮化鎵(鎂摻雜,載子濃度約為1017 cm-3)薄膜上,成功製備氧化鋅奈米線/N型氧化鋅鋁薄膜結構,並完成發光二極體之晶粒製作,其尺寸為300 m 300 m。在約大於15 V的操作電壓下,以長工作距離顯微鏡可觀察到,發光二極體晶粒的部份區域放射出藍光,且發光強度隨著電壓增加而變大。但初期製作之串聯電阻極高,且電流分布不均,在改善電極形狀後,可以有效增加電流分布的範圍,並且經過製程順序的調整,能有效改善因快速熱退火處理對鋁電極產生的不良影響,讓發光區域增加。未來將以快速熱退火進行後處理,並檢測其電極是否形成歐姆接觸,以期提升性能,進而檢測其發光頻譜等特性。

    Light emitting diode (LED) is considered as the major next-generation luminescence technology, but nowadays insufficient light efficiency of high power LED limits its application for illumination lighting. Some research group have developed nanowrie-inserted LED structure, and the EL intensity shows that the novel LED structure can improve light efficiency effectively. ZnO nanowires grown by hydrothermal method have excellent properties such as single crystal, vertical alignment, broad area growth and simple process. Thus in this study hydrothermal method is adopted to fabricate ZnO nanowires, N-type material of LED is aluminum-doped ZnO film (AZO) deposited by RF sputtering, and P-type materials are ZnO and Mg-doped GaN film. Finally, the characteristics of N-type AZO/ZnO nanowire/P-type ZnO or P-type GaN structure LED will be studied.
    The ZnO nanowries grown by hydrothermal method are successful. The outcomes of Al doped ZnO nanowires are not well because the method was different to references. It needs to try more parameters. The thermal treatment of ZnO nanowires can reduce the green light emission which cause by defects. It’s effect on reducing resistance and energy barrier.
    P2O5 doped ZnO targets are used to deposit P-type ZnO film by O2/Ar flow rate is 3. Using sapphire with ZnO buffer layer, heating to 700 C, cooling with O2 ambiance after ZnO deposited, following by RTA treatment, might produce the p-type ZnO film. The as-grown film then treated follow by rapid thermal annealing at 900 C for 5 minutes had produced to partial p-type ZnO film. The carrier concentration is 8.7921018 cm-3. The mobility is 0.793 cm2 / V-s. The resistivity is 0.8953 -cm. The result might be the electric property transformed incompletely. The co-sputter technique will be used to fabricated P-type ZnO film continuously.
    For LED study, ZnO nanowrie/N-type AZO film have been fabricated on Mg-doped P-GaN film (carrier concentration is about 1017 cm-3), the size of LED die is 300 m  300 m. Blue emission is observed from partial area of LED die through long-distance microscope when forward-bias is above 15 V, and voltage raise leads to increasing of light intensity. After changing the electrode’s shape, it can improve the current distribution of LED to increase the lighting area. In the next step, current-voltage relation and electroluminescence (EL) spectrum will be examined.

    摘要....................................................I 總目錄..................................................V 圖目錄..................................................VII 表目錄..................................................XII 第一章 序論............................................1 1.1 前言 ..............................................1 1.2 發光二極體之簡介.....................................4 1.2.1 發光二極體之原理 .............................4 1.2.2 發光二極體之結構..............................5 1.2.3 發光二極體之發光效率...........................7 1.3 氧化鋅材料..........................................13 1.3.1 氧化鋅之材料特性..............................13 1.3.2 氧化鋅之發光機制..............................14 1.3.2.1 紫外光放射.................................14 1.3.2.2 綠光放射..................................15 第二章 文獻回顧..........................................19 2.1 氧化鋅奈米線/奈米柱發光二極體之製作......................19 2.1.1 有機金屬化學氣相沉積法.........................19 2.1.2 化學氣相沉積法................................22 2.1.3 氣相傳輸法...................................23 2.1.4 電化學沉積法.................................23 2.1.5 水熱法......................................25 2.2 P型氧化鋅薄膜之製作..................................49 2.3 研究動機與目的......................................55 第三章 實驗設計與規劃.....................................56 3.1 氧化鋅奈米線之改質...................................56 3.1.1 氧化鋅奈米線摻雜鋁之製備.......................56 3.1.2 氧化鋅奈米線之熱處理..........................57 3.2 元件設計...........................................59 3.2.1 發光二極體結構之設計..........................59 3.2.2 光罩設計....................................61 3.3 實驗規劃與製程......................................65 3.3.1 同質結構氧化鋅奈米線發光二極體之製作.............65 3.2.2 異質結構氧化鋅奈米線發光二極體之製作.............67 3.4 實驗設備..........................................74 第四章 實驗結果與討論....................................84 4.1 氧化鋅奈米線之改質..................................84 4.1.1 氧化鋅奈米線摻雜鋁之SEM分析...................84 4.1.2 氧化鋅奈米線摻雜鋁之EDS分析...................85 4.1.3 氧化鋅奈米線熱處理之PL分析....................86 4.2 P型氧化鋅薄膜之製備.................................91 4.2.1 氧化鋅磷薄膜濺鍍參數.........................91 4.2.2 RTA參數測試................................93 4.2.3 氧化鋅緩衝層................................94 4.3 n-AZO/ZnO NWs/p-GaN異質結構LED之製作...............104 4.3.1 LED之製作與檢測.............................104 4.3.2 LED性能之改善...............................111 第五章 結論與未來展望.................................117 5.1 結論.............................................117 5.2 未來展望..........................................119 參考文獻...............................................120

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