Single-wall carbon nanotubes (SWNT) produced by HiPCP method and purified by thermal oxidation in air have been studied by impedance spectroscopy. The purity of nanotubes was estimated as 99% . The dc conductivity measurements were carried out at temperatures 77-450 K. High pressure has been generated in the diamond anvil cell (DAC) with anvils of the "rounded cone-plane" type made of synthetic carbonado-type diamonds. These anvils are good conductors, permitting measurement of the resistance of samples placed between the anvils in the DAC by using the anvils as the electrical contacts to the sample.
The activation energy of the SWNT was estimated from the temperature dependences of resistivity.Temperature dependences of HiPCO SWNT resistivity were plotted and analysed. Activation energy dependences of pressure were analysed.
This work was supported in part by grant BRHE EK-005-X1 (Ural research educational center "Advanced materials").
 V. Karachevtsev et al, Photoelectric and optic properties of fullerenes, 2002, 179.