Stoichiometry and infrared absorption of amorphous a-C1−xNx:H carbon nitride films

Abstract

Stoichiometry, bonding configurations and structural properties of plasma-deposited hydrogen-rich amorphous carbon nitride a-C1−xNx:H (0<x<0.20) films have been investigated using infrared and Raman vibrational spectroscopies, along with x-ray photoemission spectroscopy at the C and N K-edges. With increasing N incorporation in a-C1−xNx:H, the total H content decreases slightly and C–H vibrations are progressively replaced by N–H vibrations. The dominant bonding configuration is C=N throughout the composition range, although C=N and C–N saturate above 10 N at. %, and C≡N configurations steadily increase throughout the stoichiometry range. A strong conjugation of imine (C=N) and nitrile (C≡N) groups with aromatic rings is evidenced while the Raman signature of the sp2 C phase indicates an increase in the D to G peak intensity ratio, related to some ordering of the sp2 clustered phase.