  The effect of purification on room temperature electronic transport
properties of single-wall carbon nanotubes (SWNT) was studied by submerging
samples into liquid mercury. The conductance plots of purified SWNTs showed
plateaus, indicating weak dependence of the electrical resistance on the length
of the tube connecting the electrodes, providing evidence of quasi-ballistic
conduction in SWNTs. The electronic mean free path of the purified SWNTs
reached a few microns, which is longer than that of the as-produced SWNTs, and
which is consistent with the calculation based on the scattering by acoustic
phonons.
