Studies of electronic distribution in potassium-doped mats of single-walled carbon nanotubes, double-walled carbon nanotubes, and peapods

In this work, we have performed a systematic study of the electrical transport properties both the resistivity and the thermoelectric power on bundles of single-walled carbon nanotubes SWCNTs , double-walled carbon nanotubes DWCNTs , and peapods derived from the same batch of initial SWNTs during in situ doping with potassium donor . The charge transfer effects in K-doping are similar in SWNTs and DWNTs, but drastically different in C60 at SWNTs. An impurity level associated with the chain of C60 in the band gap of the tube with the Fermi level pinned near the top of the valence band, leading to the p-type behavior for the peapod. Significant charge transfer is found to occur only in the case of very low coverage of these nanostructures. © 2008 American Institute of Physics. DOI: 10.1063/1.2952049