Raman spectroscopy of carbon nanotubes

The basic concepts of the geometrical, electronic and vibrational (phononic) structures of carbon nanotubes (CNTs), as well as the van Hove singularities appearing in their electronic Density of States are here presented, together with a description of the main bands of their Resonant Raman spectra. In particular, the following bands are reported: 1) the Radial Breathing Modes (RBM), typical of Single Wall Carbon Nanotubes, from which information about their diameter and quirality is extracted; 2) the tangencial G band, whose spectral profile reveals the semiconductor or metallic character of the nanotubes; and 3) the D (Disorder induced) and G' (D overtone) bands. From the dispersive behaviour of the last two bands, it is possible to extract information about the fine structure of the valence and conduction bands of the CNTs. Moreover, such bands act as sensors of residual strains in composites based on CNTs. Some aspects of the Raman spectroscopy of carbon nanotubes, to be developed in the near future, are also indicated.