Characterization of carbon nanotubes using Raman excitation profiles

Canonico, M.; Adams, G. B.; Poweleit, C. D.; Menéndez, José; Page, J. B.; Harris, Gary; Meulen, H.P. van der; Calleja, J.M.; Rubió, J.

doi:10.1103/physrevb.65.201402

Cited by 31 publications

(46 citation statements)

References 36 publications

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“…For a band-to-band transition, assuming a parabolic shape of the valence and conduction bands, the following simplified expression of the Raman intensity has been derived [22,35]:…”

Section: Resultsmentioning

confidence: 99%

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

et al. 2016

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We examine the excitonic nature of the E 33 optical transition of the individual free-standing index-identified (23,7) single-walled carbon nanotube by means of the measurements of its radial-breathing-mode and G-mode Raman excitation profiles. We confirm that it is impossible to determine unambiguously the nature of its E 33 optical transition (excitonic vs band to band) based only on the excitation profiles. Nevertheless, by combining Raman scattering, Rayleigh scattering, and optical absorption measurements on strictly the same individual (23,7) single-walled carbon nanotube, we show that the absorption, Rayleigh spectra, and Raman excitation profiles of the longitudinal and transverse G modes are best fitted by considering the nature of the E 33 transition as excitonic. The fit of the three sets of data gives close values of the transition energy E 33 and damping parameter 33 . This comparison shows that the fit of the Raman excitation profiles provides with good accuracy the energy and damping parameter of the excitonic optical transitions in single-walled carbon nanotubes.

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“…For a band-to-band transition, assuming a parabolic shape of the valence and conduction bands, the following simplified expression of the Raman intensity has been derived [22,35]:…”

Section: Resultsmentioning

confidence: 99%

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

et al. 2016

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“…In contrast to the luminescence results, which reported a maximum intensity for close-to-armchair tubes and no emission from zig-zag tubes, we clearly observed zig-zag or close-to-zigzag tubes as well. The (13,0), (11,0), and the (10,0) tube show that zig-zag tubes are present in the sample. These tubes as well as the (14,1) tube were not observed by photoluminescence.…”

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confidence: 92%

“…An elegant approach is to record Raman resonance profiles [10,11,12,13], with maximum intensity close to the real transitions in the electronic band structure. Resonance profiles from nanotubes in solution were first reported by Strano et al [14]; their (n 1 , n 2 ) assignment to the transition energies was based on the RBM frequency to tube diameter relationship of Ref.…”

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Chirality Distribution and Transition Energies of Carbon Nanotubes

et al. 2004

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From resonant Raman scattering on isolated nanotubes we obtained the optical transition energies, the radial breathing mode frequency and Raman intensity of both metallic and semiconducting tubes. We unambiguously assigned the chiral index (n1, n2) of ≈ 50 nanotubes based solely on a third-neighbor tight-binding Kataura plot and find ωRBM = (214.4±2) cm −1 nm/d+(18.7±2) cm −1 . In contrast to luminescence experiments we observe all chiralities including zig-zag tubes. The Raman intensities have a systematic chiral-angle dependence confirming recent ab-initio calculations.PACS numbers: 78.67. Ch, 78.30.Na The successful preparation of single-walled carbon nanotubes in solution where the tubes are prevented from rebundling has opened a new direction in carbon nanotube research [1,2,3,4]. Strong luminescence by direct recombination from the band gap was detected in these isolated tubes, whereas in nanotube bundles no luminescence is observed. The electronic structure of carbon nanotubes and the optical transition energies vary strongly with their chiral index (n 1 , n 2 ) [5]. Because the synthesis of nanotubes with a predefined chiral index has not been achieved so far, luminescence experiments were carried out on tube ensembles with unknown composition of chiral angles. Several attempts to assign the chiral index (n 1 , n 2 ) to the experimentally observed luminescence peaks were reported [2,4,6,7]. With a unique assignment, one could validate and possibly revise theoretical models of the electronic band structure. Moreover, such an assignment would allow to characterize the tubes after their production and to control their separation [8].Bachilo et al. suggested an (n 1 , n 2 ) assignment of the first and second transition energies in semiconducting tubes [2]. Their assignment is based on pattern recognition between experiment and theory in a plot of the second transition (excitation energy) versus the first transition (emission energy) [9]. The patterns, however, were not unique, and the frequency of the radial breathing mode (RBM) was used to find an anchoring element that singles out one of the assignments. Surprisingly, zig-zag tubes were not detected in these luminescence experiments. Bachilo et al. concluded that the concentration of tubes with chiral angles close to the zig-zag direction was very low in the sample [2].The electronic transition energies of metallic nanotubes cannot be detected by luminescence experiments. An elegant approach is to record Raman resonance profiles [10,11,12,13], with maximum intensity close to the real transitions in the electronic band structure. Resonance profiles from nanotubes in solution were first reported by Strano et al. [14]; their (n 1 , n 2 ) assignment to the transition energies was based on the RBM frequency to tube diameter relationship of Ref. [2]. The resonance profiles of the so-assigned RBM peaks were then used to find an empirical expression for the transition energies in metallic tubes.In this paper we present the transition energies of both metallic a...

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“…1(b) shows the raw 2D spectral data map after subtracting a linear background. The anti-Stokes (AS, left) and Stokes (S, middle) resonances are both clearly observed, and their intensity maxima are shifted in excitation energy by the RBM phonon energy due to the resonant enhancement for both the incoming and scattered light [20][21][22]. The two-phonon RBM peak is much weaker and shifted to higher excitation energy due to the two-phonon resonant enhancement of scattered light.…”

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Optical Determination of Electron-Phonon Coupling in Carbon Nanotubes

et al. 2007

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We report on an optical method to directly measure electron-phonon coupling in carbon nanotubes by correlating the first and second harmonic of the resonant Raman excitation profile. The method is applicable to 1D and 0D systems and is not limited to materials that exhibit photoluminescence. Experimental results for electron-phonon coupling with the radial breathing mode in 5 different nanotubes show coupling strengths from 3-11 meV, depending on chirality. The results are in good agreement with the chirality and diameter dependence calculated by Goupalov et al. PACS: 73.63.Fg, 63.22.+m The intrinsic coupling between the electronic and atomic degrees of freedom is fundamental to many transport and optical properties of condensed matter. Here we examine carbon nanotubes, a prototypical one-dimensional (1D) system under intense study for both fundamental physical properties and potential applications as transistors, sensors and optoelectronic devices. The electron-phonon (e-ph) coupling in carbon nanotubes (CNTs) is a key coupling parameter in the electronic band structure, controls Raman scattering [1], heat and electron conductivity [2], and sets an upper limit to ballistic transport [3,4]. In polar semiconductors, multi-phonon replicas in luminescence have been used to measure the Fröhlich e-ph coupling with longitudinal optical (LO) phonons in good agreement with theory [5,6]. In low dimensional systems, the electron and phonon confinement complicates the situation, with conflicting experimental results [7][8][9][10], and requiring model-dependent interpretation to extract the e-ph interaction. E-ph interactions in CNTs are due to the deformation-potential interaction, generally weaker than Fröhlich interaction in polar materials. Nonetheless, evidence of e-ph coupling in CNTs are observed in photoluminescence phonon replicas [11], the Kohn anomaly manifested in the phonon dispersion and line-widths in metallic nanotubes [12] and temperature dependence of optical transition energies [13,14]. However, direct measurements of e-ph coupling in CNTs are lacking.

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Characterization of carbon nanotubes using Raman excitation profiles

Cited by 31 publications

References 36 publications

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

Chirality Distribution and Transition Energies of Carbon Nanotubes

Optical Determination of Electron-Phonon Coupling in Carbon Nanotubes

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