Hydrogen induced changes on the electronic structure of carbon nitride films

The effect of hydrogen on the electronic structure of amorphous carbon-nitrogen alloys (a-CN,) prepared by ion beam assisted (IBAD) deposition was studied by photoelectron spectroscopy. The effect of H on the local bonding structure of C and N atoms was inferred from the changes of the C Is and N Is core-level and the top of valence band spectra. The core-level spectrum of H free films are constituted of two N Is peaks identified as N bonded to sp(3) C and N bonded to sp(2) C, respectively. On increasing H content, the peak area ratio A(sp(3))/A(sp(2)) decreases and a new component associated with NH bonds emerges at 399.1 eV. Simultaneously, new features are observed at the top of the valence band. Besides the increasing NH absorption band (3350 cm(-1)), infrared spectra suggest a modification of the former disordered aromatic rings to a more Linear configuration. All the experimental information indicate that H promotes a polymeric-like structure. (C) 1998 Elsevier Science B.V. All rights reserved.