Electrical transport properties of mono-dispersed single-wall carbon nanotubes formed in channels of zeolite crystal

We report the electric transport properties of mono-sized carbon nanotubes fabricated in the channels of AlPO4-5 zeolite crystals. From X-ray data, the carbon nanotubes are shown to have a diameter of similar to 5 A. Due to the large curvature, LDA calculations show the nanotubes to have a finite density-of-states at the Fermi level for all possible nanotubes consistent with the measured diameter. However. transport measurements show the temperature dependence to be non-metallic, This could be due to electron localization caused by imperfections and impurities in the nanotubes. The observed temperature dependence of zero-field conductance. In(sigma) similar to 1/root (T) over bar, supports the 1D hopping transport process. (C) 2000 Elsevier Science B.V. All rights reserved