Terahertz Spectroscopy of Single-Walled Carbon Nanotubes in a Polymer Film: Observation of Low-Frequency Phonons

Kumar, Sunil and Kamaraju, N and Karthikeyan, B and Tondusson, M and Freysz, E and Sood, AK (2010) Terahertz Spectroscopy of Single-Walled Carbon Nanotubes in a Polymer Film: Observation of Low-Frequency Phonons. In: Journal of Physical Chemistry C, 114 (29). pp. 12446-12450.

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Abstract

We investigate the dielectric response of single-walled carbon nanotubes dispersed in poly(vinyl alcohol) matrix by using terahertz time domain spectroscopy. Frequency-dependent real and imaginary parts of the complex dielectric function are measured experimentally in the terahertz regime. The low-frequency phonons of carbon nanotubes, though predicted theoretically, are directly observed for the first time at frequencies 0.26, 0.60, and 0.85 THz. Further, a broad resonance is observed at 1.15 THz associated with the longitudinal acoustic mode of vibration of straight-chain segments of the long polymeric molecules in the film. The latter is observed at 1.24 THz for a pristine polymer film and has been used to derive the size of crystalline lamellae in the film.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry C
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	11 Aug 2010 06:19
Last Modified:	19 Sep 2010 06:13
URI:	http://eprints.iisc.ac.in/id/eprint/31215

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