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) depositi on was studied by photoelectron spectroscopy. The effect of H on the l ocal 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. T he core-level spectrum of H free films are constituted of two N Is pea ks identified as N bonded to sp(3) C and N bonded to sp(2) C, respecti vely. On increasing H content, the peak area ratio A(sp(3))/A(sp(2)) d ecreases and a new component associated with NH bonds emerges at 399.1 eV. Simultaneously, new features are observed at the top of the valen ce band. Besides the increasing NH absorption band (3350 cm(-1)), infr ared 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 Elsevie r Science B.V. All rights reserved.