  Intrinsic carrier transport properties of single-walled carbon nanotubes are
probed by two parallel methods on the same individual tubes: the contactless
dielectric force microscopy (DFM) technique and the conventional field-effect
transistor (FET) method. The dielectric responses of SWNTs are strongly
correlated with electronic transport of the corresponding FETs. The DC bias
voltage in DFM plays a role analogous to the gate voltage in FET. A microscopic
model based on the general continuity equation and numerical simulation is
built to reveal the link between intrinsic properties such as carrier
concentration and mobility and the macroscopic observable, i.e. dielectric
responses, in DFM experiments. Local transport barriers in nanotubes, which
influence the device transport behaviors, are also detected with nanometer
scale resolution.
