Electrostatics of individual single-walled carbon nanotubes investigated by electrostatic force microscopy.

We report an experimental study of static charge distribution in individual single-walled carbon nanotubes grown on a Si+115 nm SiO2 substrate. From these experiments, we conclude that charges are distributed uniformly along the nanotubes. We demonstrate that electrostatic force microscopy can accurately measure the amount of charges per unit length. We found that this amount is diameter dependent and in the range of 1 electron per nanometer for a 2.5 nm nanotube at a potential of -3.5 V.