Indexing of individual single-walled carbon nanotubes from Raman spectroscopy

Abstract

From combined Raman spectroscopy and electron diffraction studies on several freestanding single-walled carbon nanotubes (SWNTs), we define Raman criteria which correlate the main features of the Raman spectrum (radial breathing mode and G modes) and the optical transition energies with the structure of the SWNT under investigation. On this basis, we discuss the possibilities to determine the (n,m) indices of an individual SWNT from a single wavelength Raman experiment. We show the efficiency of this approach in assigning the (n,m) structure of different individual nanotubes including all types of achiral SWNTs. Finally, the limits and the accuracy of the method are discussed

Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes

“…The Raman spectrum in the G-band region displays longitudinal optical and transverse optical optical phonon modes at 1,591.5 and 1,576.5 cm À 1 , respectively (Fig. 2c), whose narrow spectral widths and frequency difference confirm a single 2 nm in diameter semiconducting nanotube is investigated 22,25 . Similar results were obtained for a second semiconducting type I nanotube of diameter d ¼ 1.83 nm, identified as a (14,13) SWNT ( Fig.…”

“…Their diameters, d (nm), were extracted from the frequencies of their radial breathing modes (RBMs) using the relation o RBM (cm À 1 ) ¼ 204/d þ 27 for suspended nanotubes 21,22 . Their chiral indices were subsequently identified by comparing the optical resonances with the spectral position and spacing of the different excitonic transitions predicted by Kataura plots [23][24][25] (for more details see Supplementary Note 1 and Supplementary Table S1). …”

Horizontally-aligned carbon nanotubes arrays and their interactions with liquid crystal molecules: Physical characteristics and display applications

“…These peaks are attributed to TO mode (G − line) and LO mode (G + line) SWNTs, respectively. 5,28 The lorentzian shape of the fitting curves indicate that the as-grown h-al-SWNT arrays consist mainly of semi-conducting nanotubes. The inset in Figure 3(b) displays a polar plot of the Raman intensity of the G band for various angles between the polarization of the incident laser light and the nanotube axis ; the spectra were recorded in the VV configuration.…”

Non-adiabatic phonon dispersion of metallic single-walled carbon nanotubes

“…For a long time, the intense high-frequency Raman G band has not been used for such purposes except for identification of the nanotubes as metallic or semiconducting [6]. The recent theoretical predictions of the G band frequency in the adiabatic approximation [7] and with dynamic corrections [8,9], have made it possible to use the experimental data from this band to support the nanotube characterization [10]. The behavior of the G band with varying temperature [11], strain [12], and charge doping [13] provides additional important information about the nanotubes under different conditions.…”

“…Raman data for isolated, well-identified nanotubes, are still quite rare. Combined electron diffraction and Raman scattering methods allowed the identification of freestanding S nanotubes on a metallic grid with indices, diameters, G -and G + bands, as follows: (12, 8) [10]. In Raman and Rayleigh scattering experiments on nanotubes grown across a wide slit [21] the G -band of the metallic nanotube (12, 3) with d = 1.08 nm was observed at 1540 cm -1 .…”