14 January 2000 Ž . Chemical Physics Letters 316 2000 186–190 www.elsevier.nlrlocatercplett Resonant Raman study of the structure and electronic properties of single-wall carbon nanotubes Laurent Alvarez a , Ariete Righi a , Tony Guillard b , Stephane Rols a,c , ´ Eric Anglaret a, ) , Daniel Laplaze a , Jean-Louis Sauvajol a a Groupe de Dynamique des Phases Condensees, UMR CNRS 5581, UniÕersite Montpellier II, 34095 Montpellier Cedex 5, France ´ ´ b IMP-CNRS Odeillo, UPR CNRS 8521, 66125 Font-Romeu, France c Institut Laue-LangeÕin, 38042 Grenoble, France Received 3 August 1999; in final form 21 October 1999 Abstract Ž . We investigate the laser-energy dependence of the Raman profile of single-wall carbon nanotube SWNT samples with various distributions of diameters. We show that resonant Raman is an efficient tool for the study of the structure and electronic properties of SWNT. The tube diameter distribution is derived from the comparison between the experimental Ž . frequencies of the radial A breathing mode range RBM and the calculated RBM frequency of SWNT bundles. Metallic 1g or semi-conducting tubes are identified in the light of calculations of allowed optical transitions. The assignments are Ž . confirmed by the observation absence of a Breit–Wigner–Fano-like lineshape for the tangential graphite-like modes of Ž . metallic semiconducting nanotubes. q 2000 Elsevier Science B.V. All rights reserved. 1. Introduction w x The optimization of production techniques 1–4 allows the synthesis of large quantities of single-wall Ž . carbon nanotubes SWNT . This has generated an important number of studies on these promising sys- tems both for application in electronics and for basic Ž . wx science in one-dimensional 1D structures 5. SWNTs are observed usually to self-assemble into Ž . bundles of 30–500 tubes on a two-dimensional 2D w x triangular lattice 1–3,6 . They are predicted to be metallic or semiconducting, depending on their di- wx ameter and chiral angle 7 . Many Raman spec- ) Corresponding author. Fax: q33-4-67144637; e-mail: eric@gdpc.univ-montp2.fr troscopy studies have been run in order to character- ize nanotubes and to test theoretical predictions about w x their electronic and vibrational properties 8–12 . Raman scattering by SWNT has been experimentally shown to be a resonant process associated with Ž . allowed optical transitions AOT between spikes in w x the 1D electronic density of states 13 which fall in the visible and near-infrared range. The energies of w x the AOT have been measured 14 or calculated in w x the zone-folding scheme by several groups 7,13,15 and found to depend both on the diameter and metallic or semiconducting character of the tubes. w x Kataura et al. 15 recently extended the calculations to a large series of tubes with various diameters and helicities. In Fig. 1 are pictured the ranges of ener- gies where resonance is expected to occur theoreti- 0009-2614r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. Ž . PII: S0009-2614 99 01291-9