Medium-range order in pyrolyzed carbon films: Structural evidence related to metal-insulator transition

Meenakshi, V and Subramanyam, SV (2002) Medium-range order in pyrolyzed carbon films: Structural evidence related to metal-insulator transition. In: Journal of Applied Physics, 92 (3). pp. 1372-1379.

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Abstract

Structural properties of carbon films prepared by the pyrolysis of tetra chloro phthalic anhydride are investigated in an attempt to correlate it with the metal-insulator transition observed earlier as a function of deposition temperature, from electrical transport studies. Anomalous features are observed which evolve as the pyrolysis temperature is varied from 700 to 900°C. This includes prepeaks in the x-ray diffraction pattern in the region less than 1 ${\AA}^{-1}$ providing evidence for medium range order, and a broad shoulder around 1200 $cm^{-1}$ in the Raman spectra, which are seen in addition to the usually observed peaks in amorphous carbon films. A simple model is proposed according to which presence of "polymeric domains" containing chains of carbon atoms with single and double bond alternation (-C=C-), in a predominantly aromatic ring structure, could give rise to the anomalous features.

Item Type:	Journal Article
Publication:	Journal of Applied Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright for this article belongs to American Institute of Physics (AIP).
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	21 Nov 2007
Last Modified:	19 Sep 2010 04:17
URI:	http://eprints.iisc.ac.in/id/eprint/2545

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