Conduction mechanism of the bamboo-shaped multiwalled carbon nanotubes

Temperature-dependent resistivity measurements were carried out on bamboo-shaped multiwalled carbon nanotubes (BS-MWNTs) vertically grown on cobalt catalyst deposited Al2O3/Ti substrates and iron catalysts deposited SiO2/Ti substrates at 750 - 950 degreesC by thermal chemical vapor deposition. The resistivity decreased with increasing growth temperature, and showed lower values in the case of SiO2/Ti substrates than in the case of the Al2O3/Ti substrates. A heterogeneous model, compromising quasi 1-D metal terms and the fluctuation-induced tunneling through thin barriers between metallic regions was introduced to explain the conduction mechanism. As a result, it was proposed that the important factor for the conduction mechanism of BS-MWNTs is the inter-sheet conduction by discontinuous graphitic sheets at the compartments.