Impact of charged impurity scattering in carbon nanotubes

We have measured the transport property of carbon nanotubes as a function of density of charged impurities. Length-dependent resistance measurements were used to eliminate the contribution from the contact resistance in our data. By knowing the exact density of charged impurities on nanotubes, we measure the scattering cross section of individual adsorbed charge impurity. Measurements on different nanotubes are used to reveal the effect of pseudospin conservation on electronic transport in metallic and semiconducting carbon nanotubes upon addition of long-range impurities experimentally. These findings will be outlined in this talk.