Raman spectroscopy studies of carbide derived carbons

The Raman spectra of a number of carbide derived carbons (CDCs) synthesised from TiC at 700, 800, 900, 1000, 1100 and 1200 degrees C and from VC, WC, TaC, NbC, HfC and ZrC made at 1000 degrees C have been recorded using laser excitation wavelengths of 514 and 785 nm. The spectra show two main features, the D- and G-peaks situated around 1350 cm(-1) and 1600 cm(-1), respectively. The peak positions, their intensities (I-D/I-G) and full width at half maximum (FWHM), as well as their wavelength dependent dispersion, were used to obtain information about the degree of disorder in CDCs. The increasing ordering with synthesis temperature was confirmed by lower FWHM values obtained from CDCs made at higher synthesis temperatures. However, this parameter was not very sensitive to variation in ordering in CDCs made at 1000 degrees C from different carbides. The I-D/I-G was used for determination of the in-plane correlation length, which has shown to be independent of synthesis temperature and more sensitive to the choice of the precursor carbide. However, the changes in in-plane correlation length were small and barely accounted for the size of one sixfold ring. (C) 2008 Elsevier Ltd. All rights reserved.