(Invited) Electronic Scattering in One-Dimensional Carbon Nanotubes

A quasi-ballistic, semi-metallic carbon nanotube is a nearly ideal conductor for investigating scattering in the one-dimensional (1D) limit and for comparing experiment with theoretical predictions.  Recently, we have developed high resolution Kelvin Probe force microscopy (KPFM) methods of characterizing transport in single nanotubes.  KPFM images of potential gradients uniquely reveal the bias- and temperature-dependent mechanisms of scattering in nanotube devices, and clearly discriminate between contact effects and homogenous, diffusive scattering.  Using this data, a comprehensive, quantitative model has been developed that includes intrinsic energy-relaxation processes, extrinsic interactions with the surrounding environment, and the effects of point defects.  The new results show that the literature grossly underestimates the mean free path for optical phonon emission.  Defect scattering follows a mechanism similar to Poole-Frenkel conduction but with modifications accounting for the 1D geometry.  The Poole-Frenkel mechanism, which normally applies to 2D interfaces, has never been observed in the limit of a single defect limit, and its application to point defect scattering in 1D is wholly unanticipated in the theoretical literature.  This presentation will summarize these findings and their implications for nanotube devices as sensors or digital electronics.