Résumé
By combining resonant Raman spectroscopy, high resolution transmission electron spectroscopy (HRTEM) and electron diffraction experiments on individual free-standing carbon nanotubes, we have been able to determine unambiguously the intrinsic features of their phonons. In this communication we review the results obtained from these combined experiments on single-walled (SWNT)and double-walled (DWNT) carbon nanotubes. The features of the Raman-active modes of SWNT and DWNT as a function of their structure is discussed and compared with recent theoretical predictions.