The $I-V$ characteristics and tunneling effects of several carbon nanotubes are studied by electronic transport calculations with a semiclassical approach. The electrical currents are obtained by solving master equations connecting different charge states. The charging energies and electronic structures of the nanotubes are calculated by the ab initio density-functional theory. The results show that the Coulomb blockade is closely related to the structures of systems, and that the necessary condition for the Coulomb staircase to occur is that the cathode junction is narrower than that of the anode. The Coulomb staircase, evident at lower temperatures, could be suppressed by temperature elevation.

• Received 16 August 2001

DOI:https://doi.org/10.1103/PhysRevB.66.045404