Synthesis of Silicon Oxide Nanowires with Copper as Catalyst

為了得到更精簡更經濟的製程生產氧化矽奈米線，本研究在審慎的考量下採用銅金屬做為其奈米線成長觸媒，並在1000oC，1%H2/N2的氣氛下，成本s備出高排列規則性的氧化矽奈米線陣列，其平均直徑約40nm，長度約數微米。在實驗參數的研究上，對於反應溫度，時間，氣氛、基材與銅觸媒量都有研究，並提出成長機制模型。且在奈米線成長機制上，對於氣液固成長機制與氧化物輔助機制做了詳細的討論，再加上本研究的實驗結果歸納出兩者間的差異，其中最重要的是強調在有合適觸媒的情況下，反應傾向於由氣液固成長機制而非氧化物輔助機制。且在氧化矽奈米線陣列的光致發光研究上，發現其在波長250nm的激發光下，會在2.8eV (440 nm)至4.0 eV (310 nm)之間產生放射光。In order to obtain a simpler and cheaper process to produce silicon oxide nanowires, copper metal was adapt as catalyst for nanowire growing under deliberate consideration, and highly orientated silicon oxide nanowires array with 40nm diameter in average and several micrometer in length was produced at 1000oC under 1% H2/N2 atmosphere. For experimental parameters research, we studied reaction temperature, reaction time, atmosphere, base material and mount of copper catalyst, and modeled the growth mechanism. In addition, we had a detail discussion on gas-liquid-solid mechanism and oxide-assisted mechanism in nanowires growth mechanism, and within our experimental result we finally concluded the differences between this two mechanisms. In these differences, the most important one is that within proper catalyst, the reaction preferred gas-liquid-solid mechanism to oxide-assisted mechanism. Moreover, in the photoluminescence study of silicon oxide nanowires array, we found that it would emit strong light between 2.8 eV (440 nm) to 4.0 eV (310 nm) under the excitation of 250nm wavelength light.摘要 I Abstract II 目錄 III 圖目錄 V 表目錄 XII 第一章 緒論 1 第二章 理論與文獻回顧 3 2-1 氧化矽奈米線的製備方式 3 2-1-1 高溫氣化法 3 2-1-2 雷射消融法 9 2-1-3 化學氣相沈積法 11 2-1-4 模版法 13 2-2 奈米線合成機制 18 2-2-1 VLS mechanism 19 2-2-2 O-A mechanism 22 2-2-3 VLS mechanism與O-A mechanism的比較 24 2-3 光致發光簡介 30 2-3-1 冷光簡介 30 2-3-2 本質(intrinsic)與非本質(extrinsic)冷光 31 2-3-3 光的吸收與放射 36 2-4 氧化矽的PL性質 40 2-4-1 氧化矽的PL研究 40 2-4-2 SiONWs之PL研究 44 第三章 實驗方法 48 3-1 實驗藥品 48 3-2 實驗步驟 49 3-2-1 氧化鋁板上SiONWs的合成 49 3-2-2 銅箔上SiONWs的合成 51 3-2-3 SiONWs的特性分析 51 第四章 實驗結果與討論 53 4-1 Al-SiONWs的製備與PL光譜分析 53 4-2 銅金屬及反應溫度對Al-SiONWs生長的影響 58 4-3 Cu-SiONWs的製備與PL光譜分析 62 4-4 反應溫度與反應時間對Cu-SiONWs成長的影響 68 4-5 反應氣氛對Cu-SiONWs生長形態的影響 71 4-6 SiONWs反應機制 78 第五章 結論與建言 82 第六章 參考文獻 84 附錄A 氣液固成長法觸媒與最低合金熔點 9