Shell Coupling Through a Single Multiwall Carbon Nanotube

Transport properties of single multiwall carbon nanotubes at high bias voltages have been investigated in vacuum by scanning the bias voltage at room temperature. The characteristics of current-voltage exhibit a rapid increase of current, which can be well understood in terms of the density of states and multi-shell coupling. The breakdown experiment shows that the inner shells also contribute to conductance and can break at the bias voltage higher than that of the outer shells. This demonstrates that multi shells participate the transport. It is also found that the breakdown occurs at the center of the MWNT, indicating that the transport is diffusive rather than ballistic.