Ammonia sensing properties of multiwalled carbon nanotubes embedded in porous alumina templates

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• 作者：Raghu Mangu ; Suresh Rajaputra ; Patricia Clore ; Dali Qian ; Rodney Andrews ; Vijay P. Singh
• 关键词：Anodic aluminum oxide ; Carbon nanotubes ; Gas sensor ; CVD
• 刊名：Materials Science and Engineering: B
• 出版年：2010
• 出版时间：25 October 2010
• 年：2010
• 卷：174
• 期：1-3
• 页码：2-8
• 全文大小：616 K

文摘

Highly ordered anodic aluminum oxide templates were fabricated by a two step anodization process. Vertically aligned multiwalled carbon nanotube (MWCNT) arrays were grown in these templates through xylene pyrolysis, without the use of a catalyst and were integrated into a resistive sensor design. An equivalent circuit model was developed to understand the operation and to propose design changes for increased sensitivity. During the xylene pyrolysis, a thin layer of amorphous carbon (5–50 nm), forms on both sides of the template as a by-product of the CVD process. This a-C layer plays a crucial role in determining baseline resistance and the sensitivity, since it affects the current path. A study was undertaken to elucidate the dependence of sensitivity on the thickness of amorphous carbon layers, by subjecting the device to post-processing step of plasma oxidation.