Cotunneling and one-dimensional localization in individual disordered single-wall carbon nanotubes: Temperature dependence of the intrinsic resistance

We report on the temperature dependence of the intrinsic resistance of long individual disordered single-wall carbon nanotubes. The resistance grows dramatically as the temperature is reduced, and the functional form is consistent with an activated behavior. These results are described by a Coulomb blockade along a series of quantum dots. We occasionally observe a kink in the activated behavior that reflects the change of the activation energy as the temperature range is changed. This is attributed to charge hopping events between nonadjacent quantum dots, which is possible through cotunneling processes.