Relationship between composition and position of Raman and IR peaks in amorphous carbon alloys

Proper analysis of the Raman (and IR) spectra of amorphous carbon nitride-based alloys can give information on the carbon and nitrogen distributions in the material. In fact, a correlation exists between the relative carbon content in such films and the center of the G-band, and on this basis we have drawn a ‘rule of thumb’ allowing us to obtain an estimate of the carbon content from the Raman spectra. The information achievable by comparative analysis of the Raman and the IR features is discussed in the light of the presence of atoms having different electronegativities. The crucial role played by the dipolar field created locally by nitrogenated groups is also thoroughly discussed.