RAMAN-SPECTRA OF CARBON-BASED MATERIALS EXCITED AT 1064 NM

This paper reports the Raman spectra, obtained by using an excitation laser at 1064 nm, of carbon-based materials characterised by different microstructural properties and structural perfection. The use of a NIR excitation evidences new aspects of Raman activity in carbons. The E(2g) mode at 1582 cm(-1) in HOPG does not show dispersion to 1064 nm. On the other hand, in polycrystalline graphites the dependence on the exciting wavelength seems to be extended to all the bands, with the only exception of those arising from the k = 0 selection rule in the graphitic lattice. A new description of two characteristic bands of disordered carbons, the D band and its overtone, is presented.