Raman Spectra from One Carbon Nanotube M. S. DRESSELHAUS a,b , A. JORIO b , A. G. SOUZA FILHO b,d , G. DRESSELHAUS c , R. SAITO e , and M. A. PIMENTA f a Dept. of Electrical Engineering and Computer Science, b Dept. of Physics, c Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA; d Dept. de F´ ısica, Univ. Federal do Cear´a, Fortaleza - CE, 60455-760 Brazil; e Department of Electronic Engineering, University of Electro-Communications, Chofu, 182-8585 Tokyo, Japan; f Dept. de F´ ısica, Univ. Federal de Minas Gerais, Belo Horizonte - MG, 30123-970 Brazil. The use of Raman spectroscopy as a characterization tool for individual single wall carbon nanotubes is briefly reviewed. New physical phenomena occurring at the single nanotube level are discussed, with special emphasis given to the use of resonance Raman scattering for the structural determination of (n, m) for individual nanotubes, based on diameter and chirality dependent phenomena associated with the radial breathing mode, the G-band and the G ′ -band features. Examples are given to show how single nanotube spectroscopy provides insight into the use of Raman spectroscopy for the characterization of nanotube bundles and for the study of new physical phenomena occurring at the single nanotube level. Keywords: carbon nanotubes, Raman spectroscopy, Raman characterization, radial breath- ing mode, D-band, double resonance, dispersive phonon modes. INTRODUCTION The ability to carry out Raman scattering studies at the single nanotube level and to use such spectra to identify the (n, m) structural indices for an individual nanotube opens up many new possibilities for the discovery of new physical phenomena never seen before in any system, for understanding how the Raman spectra from single wall carbon nanotube (SWNT) bundles are related to the constituent SWNTs in the bundle, and for using the Raman characterization technique to carry out studies of other physical properties of SWNTs of known (n, m) values at the single nanotube level. The use of Raman spectroscopy for determining nanotube diameters and for distinguishing between metallic and semiconducting SWNTs is well known from measurements on SWNT bundles [1]. In the present review, we focus on the wealth of additional information provided by spectroscopy at the single nanotube level. The (n, m) integers are conventionally used to specify the number of unit vectors a 1 and a 2 in the graphene honeycomb structure that constitute the chiral vector (or roll-up vector)  C h = na 1 + ma 2 corresponding to the nanotube circumference [2]. Once (n, m) is known, the nanotube diameter d t and chirality, or the orientation of the carbon hexagons with respect to the nanotube axis, can be specified [2]. Raman spectra of the radial breathing mode, whereby each carbon atom in the nanotube vibrates in phase in the radial direction, give a direct measure of d t , because the radial breathing mode frequency ω RBM , is given by the relation ω RBM = α/d t , where α is found to be 248 cm −1 nm, based Mat. Res. Soc. Symp. Proc. Vol. 706 © 2002 Materials Research Society Z7.1.1 https://doi.org/10.1557/PROC-706-Z7.1.1 Downloaded from https://www.cambridge.org/core. IP address: 54.70.40.11, on 24 May 2019 at 18:46:35, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms.