Terahertz Time Domain Spectroscopy to Detect Low-Frequency Vibrations of Double-Walled Carbon Nanotubes

Kumar, Sunil and Kamaraju, Natrajan and Moravsky, Alexander and Loutfy, R. O. and Tondusson, Marc and Freysz, Eric and Sood, Ajay Kumar (2010) Terahertz Time Domain Spectroscopy to Detect Low-Frequency Vibrations of Double-Walled Carbon Nanotubes. In: European Journal of Inorganic Chemistry (27). pp. 4363-4366.

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Abstract

We have measured the frequency-dependent real index of refraction and extinction coefficient (and hence the complex dielectric function) of a free-standing double-walled carbon nanotube film of thickness 200 nm by using terahertz time domain spectroscopy in the frequency range 0.1 to 2.5 THz. The real index of refraction and extinction coefficient have very high values of approximately 52 and 35, respectively, at 0.1 THz, which decrease at higher frequencies. Two low-frequency phonon modes of the carbon nanotubes at 0.45 and 0.75 THz were clearly observed for the first time in the real and imaginary parts of the complex dielectric function along with a broad resonance centred at around 1.45 THz, the latter being similar to that in single-walled carbon nanotubes assigned to electronic excitations. Our experiments bring out a possible application of double-walled carbon nanotube films as a neutral density filter in the THz range.

Item Type:	Journal Article
Publication:	European Journal of Inorganic Chemistry
Publisher:	John Wiley and Sons
Additional Information:	Copyright of this article belongs to John Wiley and Sons.
Keywords:	Carbon; Nanotubes; Time-resolved spectroscopy; Dielectric function; Low-frequency phonons
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	08 Nov 2010 08:33
Last Modified:	28 Nov 2018 15:14
URI:	http://eprints.iisc.ac.in/id/eprint/33670

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