Multiphonon replicas in Raman spectra and conductivity properties of carbon films with different concentrations of sp1-bonds

The method of ion-plasma pulse-arc sputtering of graphite in a methane atmosphere has been employed to produce carbon films with different rate of sp1-bonds having a significant impact on the electrical conductivity of those films. Raman spectroscopy showed that the line near 2040 cm−1, corresponding to the oscillation of long carbon chains with sp1-hybridization, became more prominent with increase of methane concentration in the vacuum deposition chamber. The obtained spectra revealed multiphonon replicas of the 2040 cm−1 line that is evidently associated with the presence of defects in carbon chains.