Infrared spectra of amorphous carbon based materials

The IR absorption in amorphous carbon and carbon nitride films is discussed in terms of a phenomenological model based on similar absorptions occurring in doped polyconjugated polymers. It is proposed that the strong IR absorption band observed in the 1800-900 cm− 1 region arises from changes in the electronic structure in the micro-domains of the sp2 clusters due to long and short range charge fluxes. These charge fluxes are enhanced by the increase in the Csp2 fraction and/or the increase in the nitrogen content (with the subsequent formation of sp2 and sp1 sites) since both induce clustering of the sp2 phase and delocalization of π electrons.