Résumé
In the past, by combining resonant Raman spectroscopy and electron diffraction experiments on suspended (free-standing) individual chiral and achiral single-walled carbon nanotubes (SWNTs) we have been able to determine unambiguously the in-air and room-temperature main features of their Raman spectrum. On the base of these results, Raman criteria were defined allowing the identification of SWNTs from their Raman features only [1]. In this communication we present these criteria and we show their efficiency to assign the structure of individual carbon nanotubes [2]. Extrinsic factors that can confuse the assignment of the tubes from their Raman spectra are discussed. The Raman features are discussed with regards to theoretical predictions. Recently, by using a new-experimental set-up which combines imaging and Raman spectroscopy, a lot of Raman data were measured on free-standing nanotubes: individual SWNTs, individual SWNT bundles, individual MWNTs and individual MWNT bundles. The dependence of the Raman features of these nanotubes as a function of their structure is discussed.