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Trans.
Mater. Res. Soc. Japan, 29 (8), 3639-3642 [pdf] |
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Investigation of the Nitrogen
Effect on the Carbon Nanotube Growth by Ab-initio Calculation
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Hyo-Shin Ahn,
Tae-Young Kim, Seung-Cheol Lee, Kwang-Ryeol Lee
and Doh-Yeon Kim
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We investigated the effect of
nitrogen incorporation on the carbon nanotube (CNT) growth by ab-initio
calculation. Two possible effects of nitrogen incorporation were tested in the
present work: the reduction of the strain energy for tubular graphite sheet or
the reduction of the kinetic barrier for the CNT growth. The strain energy of
tubular form of graphite decreased as the diameter of CNT increased. The strain
energy becomes negligible when the diameter of CNT was larger than 35 Å. Hence,
the effect of nitrogen incorporation to reduce the strain energy of tubular
graphite is not significant in most cases of the CNT growth. In order to
estimate the kinetic barrier for CNT growth, transition state calculations were
carried out for every step of carbon attachment. The kinetic barrier for carbon
attachment without nitrogen was estimated to be 176meV for zigzag growth edge
or 160meV for armchair edge. However, the nitrogen incorporation significantly
reduced the kinetic barriers in a certain configuration. Especially, when
nitrogen is located on the top edge of zigzag growth front, the kinetic barrier
disappeared. Enhanced growth of CNT by nitrogen incorporation was discussed in
terms of the reduction of the kinetic barrier. |
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