Synthesis of Fe-filled CNT forest with high efficiency by using Al2O3 buffer layer
Date Issued
2010
Date
2010
Author(s)
Chiang, Yen-Yu
Abstract
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.
Subjects
Fe-filled Carbon Nanotube forests
alumina (aluminum oxide)
buffer layer
growth rate
aspect ratio
Type
thesis
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