Logo der Universität Wien

Optical and phonon properties of index-identified double-walled carbon nanotubes

Levshov, Dmitry (Southern Federal University, Rostov-on-Don, RUS); Tran, Huy Nam (Laboratoire Charles Coulomb, University of Montpellier, Montpellier, FRA); Michel, Thierry (Laboratoire Charles Coulomb, University of Montpellier, Montpellier , FRA); Popov, Valentin (University of Sofia, Faculty of Physics, Sofia, BGR); Blancon, Jean-Christophe (Institut Lumière et Matière, University of Lyon, Villeurbanne , FRA); Arenal, Raul (Instituto de Nanociencia de Aragón, Zaragoza, ESP); Zahab, Ahmed Azmi (Laboratoire Charles Coulomb, University of Montpellier, Montpellier, FRA); Yuzyuk, Yuri (Southern Federal University, Rostov-on-Don, RUS); Sauvajol, Jean-Louis (Laboratoire Charles Coulomb, University of Montpellier, Montpellier, FRA); Paillet, Matthieu (Laboratoire Charles Coulomb, University of Montpellier, Montpellier , FRA)

In this communication, we report on the study of intrinsic Raman features of radial breathing-like modes (RBLM) and tangential modes (G modes), as well as of optical properties of individual, spatially isolated, suspended (environment-free) doublewalled carbon nanotubes (DWNTs) by combination of High-resolution electron microscopy, Electron Diffraction, Resonant Raman spectroscopy, Rayleigh spectroscopy and Optical absorption. We demonstrate that these features can only be understood in a coherent way by considering the mechanical and electronic coupling between two concentric layers of the DWNTs. These couplings determine the conditions of observation of the modes in the Raman spectra and affect the frequencies of the RBLM [1,2] and G modes [3,4]. We focus in particular on the dependence of G modes as a function of the structural parameters of index-identified DWNTs with different electronic configurations. We find a clear downshift of the inner-layer G modes with respect to the corresponding G modes in equivalent single-walled nanotubes, when the interlayer distance is larger than the nominal van der Waals distance of about 0.34 nm [3]. This experimental behavior is understood by considering the effects of the relaxation of the layers and the interlayer interaction between the relaxed layers [5], both effects contributing to the negative pressure felt by the inner and outer layers.

[1] D. L. acknowledge financial support of Russian Science Foundation (Grant 15-12-10004)

[2] D. Levshov et al, Nano Lett. 2011. Vol. 11, N11. P. 4800–4804.

[3] D. Levshov et al, J. Nanophotonics. 2016. Vol. 10, N1. P. 012502.

[4] Levshov et al, J. Phys. Chem. C. 2015. Vol. 119, 40. P. 23196–23202.

[5] H.N. Tran, Raman scattering and optical spectroscopies of individual pristine and functionalized carbon nanotubes // PhD, University of Montpellier, 2016. V. N. Popov, (unpublished results).

NT16 Organizing Committee | Boltzmanngasse 5 | 1090 Vienna | Contact us