Chirality distribution in single walled carbon nanotube films by spectroscopic ellipsometry

We report an experimental technique that determines the chirality distribution in single wall carbon nanotube (SWCNT) films. Films of CoMoCat SWCNTs and SWCNTs enriched in (6,5) chirality are considered. Classical methods like photoluminescence spectroscopy frequently give incomplete distribution. In this way, spectroscopic ellipsometry is used to determine the dielectric function of SWCNT film. The chirality abundance obtained by analysing the ellipsometric data with a tight binding model is compared with that deduced from photoluminescence excitation spectroscopy. We demonstrate that ellipsometry is an efficient tool for a complete and quantitative determination of the chirality distribution and the metallic/semiconducting ratio.