Radial breathing mode resonance Raman cross-section analysis in single-walled carbon nanotubes

Abstract

Single-walled carbon nanotubes (SWNT) samples usually consist of a mixture of several diferent SWNT species, whose diferent properties can be determined from a pair of indices (n;m), or, equivalently, from its diameter and chiral angle (dt; ). Here, we use resonance Raman spectroscopy (RRS), a technique widely used for the characterization of SWNT samples, to quantitatively determine the diameter distribution of such a sample. In order to do this, we focus on the Raman feature associated with the radial breathing mode (RBM) vibration of theSWNTs, which, given its frequency and the excitation wavelength, can be uniquely associated with a single SWNT species. Its intensity depends not only on the abundance of its related species, but also on the eciency with which the SWNT causes Raman scattering (its RBM cross-section). By combining high resolution transmission electron microscopy (HRTEM) and RRS on the same standard SWNT sample, we calibrated and determined the RBM cross-section of a wide variety of SWNT species. Thus, we propose a method for the determination of the diameter distribution of any SWNT sample with only RRS measurements.