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