Infrared active phonons in single-walled carbon nanotubes

Infrared-active phonons in carbon nanotubes

“…[6][7][8] Clearly, our data and the ab initio calculations are opposite to the results of Kulh- ͒ are found. The experimental downshift of radial and tangential modes when the diameter increases 8 is opposite to the predictions of the ab initio calculations.…”

“…For instance, two modes located around 873 and 1597 cm −1 have been reported in Ref. 6. These modes are upshifted with respect to the A 2u ͑868 cm −1 ͒ and E 1u ͑1590 cm −1 ͒ ir-active modes of graphite.…”

“…These modes are upshifted with respect to the A 2u ͑868 cm −1 ͒ and E 1u ͑1590 cm −1 ͒ ir-active modes of graphite. 6,10 By contrast, in other investigations performed on functionalized SWCNTs 7 or industrially produced SWCNTs, 8 both ir-bands are downshifted by comparison to the related infrared-active modes in graphite. In Ref.…”

“…[5][6][7][8][9] Most of the observations and conclusions of these previous studies are sometimes opposite. For instance, two modes located around 873 and 1597 cm −1 have been reported in Ref.…”

Variable range hopping and/or phonon-assisted tunneling mechanism of electronic transport in polymers and carbon nanotubes

“…As seen in Table 1, among the set of parameters used for the calculation of PhAT rate W (E T ) dependences, the carriers' effective mass is known from literary sources, while the depth of the centre T and, in some cases, electric field strength can be assessed applying the data from the experiment. We want to note that there exist a grand variety of vibration modes in the energy range, for example, in the carbon nanotube case, from about 1 to 200 meV [58], [67][68][69][70], and thus the phonons of various energies may take part in the tunneling process. However, at low temperatures only phonons of small energy can be effective because a population of phonons of higher energy would be negligible.…”