Characterization of carbon nanotubes using Raman excitation profiles

Abstract

Resonance Raman excitation profiles for several radial-breathing modes in carbon nanotubes have been measured using tunable lasers. It is shown that the line shapes of the excitation profiles are a powerful tool for the characterization of the nanotubes. In particular, profiles that follow theoretical predictions for a single one-dimensional singularity in the joint density of states can be assigned to armchair tubes. These assignments do not rely on the quantitative details of electronic structure calculations.