以氧化鋁為緩衝層合成高成長效率之填鐵奈米碳管叢

奈米碳管近年以其優異的電磁與機械性質引起各方注目，原因在於具有鍵結上的特殊構型以及極小的尺寸，應用前景看好。填鐵奈米碳管叢是在合成碳管同時填入鐵奈米線於碳管中空處，由於過度元素(鐵、鈷、鎳)具軟磁性，因而更加彰顯材料之磁性能，目前以基板成長的填鐵碳管叢還有許多改善的空間，故以氧化鋁為緩衝層輔助合成填鐵碳管叢，本研究中以化學氣相沉積法做碳管的製備，並探討氧化鋁的使用與否在各種參數條件下的影響。為了探討合成速率與碳管叢高度，所以先固定成長時間以及填鐵來源-二茂鐵的用量，而主要研究的參數條件有:氫氣與外加碳源使用與否的影響、反應溫度、二茂鐵昇華溫度、氫氣與氬氣流量、時間參數與氫氣退火與多層碳管叢等。實驗結果發現幾乎在所有參數下有使用氧化鋁輔助成長的碳管叢，在合成效率以及填鐵狀況上都較僅使用純鐵薄膜的佳，簡言之，使用氧化鋁可突破成長高度的限制並且增加奈米鐵線的連續性，以10分鐘的合成時間可成長100 ~ 700 μm的填鐵碳管叢，成長速率最高約有1183 nm/s，而填入的鐵奈米線之連續長度可至 3.8 μm，配合因基板控制所得到較小的線徑，長徑比也可達 450，大幅增加運用空間與使用價值。而由熱重分析儀的檢測結果，碳管叢鐵含量比未使用氧化鋁的實驗高出2~3倍以上。

關鍵字

填鐵奈米碳管叢；氧化鋁；緩衝層；成長效率；長徑比

並列摘要

Carbon nanotubes have given rise to attention for its excellent magnetic and mechanical properties in recent years. The reason is that a bond in the special configuration and tiny size, and application prospects. The magnetic behavior is enhanced by means of filling iron nanowire into the hollow center of nanotube, which is as grown Fe-filled carbon nanotube forests. Synthesis of carbon nanotue by using substrate growth is have much improvement, there are still insufficient. In this study, we aim to synthesis of Fe-filled carbon nanotubes forests by CVD and using alumina as the assistance. And also study the influence at many parameters about the alumina use or not. We first fixed growth time and the amount of ferrocene, the purpose is to study the growth height and growth rate. The major changes in conditions include: reactive temperature, sublimation temperature of ferrocene, the flow rate of hydrogen and argon, time parameters, hydrogen annealing and multi-layer CNT forests. The result indicated that the growth rate of Fe-filled CNT forests by alumina-assis- ted is much better than growth by Fe film only, and no matter what growth environment. In short, the alumina buffer layer which can enhanced the growth rate of Fe-filled CNT, and increase the continuity of fe nano wires that encapsulated in CNT. The synthesis time of 10 minutes can grow 100 ~ 710 μm of height, i.e. the fastest growth rate is about 1183 nm/s. And the Fe nano wires can be uninterrupted for 3.8 μm, with the controlled smaller and uniform diameter; the aspect ratio of Fe nano wire can reach 450. The coercivity of the Fe-filled CNT forests increase with increasing aspect ratio of the Fe nanowires. And the result of TGA showed that iron content in the CNT forest which growth by alumina-assisted is two to three time more than not assisted.

並列關鍵字

Fe-filled Carbon Nanotube forests ； alumina (aluminum oxide) ； buffer layer ； growth rate ； aspect ratio

參考文獻

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[2] M. S. Dresselhaus, G. Dresselhaus, and R. Saito, “Physics of carbon nanotubes,” Carbon, Vol. 33, No. 7, pp. 883-891, 1995

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[5] A. Gohier, C.P. Ewels, T.M. Minea, M.A. Djouadi, “Carbon nanotube growth mechanism switches from tip- to base-growth with decreasing catalyst particle size,” Carbon, 46, 1331-1338, 2008

[6] Song I.K., Cho Y.S., Choi G.S., Park J.B., Kim D.J., “ The growth mode change in carbon nanotube synthesis in plasma-enhanced chemical vapor deposition,” Diamond Relat. Mater., 13 (4-8):1210–3, 2004

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以氧化鋁為緩衝層合成高成長效率之填鐵奈米碳管叢

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