Vibration modes of carbon in hydrogenated amorphous carbon modified with copper

Activation in IR absorption of quasi-Raman vibration modes of graphene planes was studied in a-C:H modified with copper; these modes are forbidden in the absence of copper. Parameters of the quasi-Raman bands G and D in optical absorption in the region of carbon-carbon mode vibrational frequencies and the parameters of true Raman bands are compared in the Raman spectra of pure a-C:H and in that modified with copper. It is stated that the close coincidence of the frequencies of the true Raman bands in a-C:H and quasi-Raman bands in a-C:H(Cu) indicates that the interaction of copper atoms with the carbon matrix leaves the graphene rings practically intact and can be regarded as intercalation. To identify the observed quasi-Raman and the satellite bands, correlations between their parameters are considered. The sizes of graphite-like clusters and their dependence on the copper content in the film were evaluated from the ratios between the integrated intensities of D and G bands.