Raman modes in index-identified individual single-walled and multi-walled carbon nanotubes

• Main Author: Levshov, Dmitry
• Language: English
• Published: Université Montpellier II - Sciences et Techniques du Languedoc 2013
• Subjects: [PHYS:COND:CM_GEN] Physics/Condensed Matter/Other; [PHYS:COND:CM_GEN] Physique/Matière Condensée/Autre; Raman spectroscopy; Carbon nanotube; Electron diffraction
• Online Access: http://tel.archives-ouvertes.fr/tel-01023001; http://tel.archives-ouvertes.fr/docs/01/02/30/01/PDF/37508_LEVSHOV_2013_archivage-1_cor.pdf

The main objective of this work is the fundamental physical study of individual isolated carbon nanostructures in order to address their intrinsic vibrational and optical properties and also to estimate and quantify the environmental effects. For these purposes, we synthesized individual single- and multi-walled carbon nanotubes by chemical vapour deposition method on dedicated substrates. The main aspect of the work involves the combined use of different experimental probes on the same individual nanostructures. We performed a complete structure analysis by electron diffraction and high-resolution electron microscopy and the measurement of the Raman spectra on these individual nanostructures. Several important environmental effects were evidenced for the first time, e.g. the effect of mechanical coupling (van-der-Waals interaction) between the layers of double-walled carbon nanotubes leading to the change in the low-frequency Raman modes and the optical resonance conditions. Moreover the behaviour of high-frequency modes of double-walled tubes was also analysed and described. As a result of this work several experimental criteria for structure diagnostics of multi-walled carbon nanotubes were proposed.