Electrical conductance and breakdown in individual CNx multiwalled nanotubes

Doping of carbon nanotubes with nitrogen during growth strongly modifies their electronic structure through n-type doping. This provides the possibility of producing nanotubes with high conductances, independent of tube chirality. To date, electrical measurements on individual nitrogen-doped multiwalled nanotubes (CNx MWNTs) have reported surprisingly low conductances (∼0.01G0). Here the authors present high conductance (1.0±0.3G0) measurements at low bias for individual CNx MWNTs. Conductance increases linearly with voltage at a rate of 0.7±0.2G0∕V until the threshold for electrical breakdown is reached. Discrete current steps of 20±10μA are then observed.