PULSED LASER DEPOSITION OF DIAMOND-LIKE HYDROGENATED AMORPHOUS-CARBON FILMS

Diamondlike hydrogenated amorphous carbon films have been deposited for the first time by pulsed ruby laser deposition (PLD) from pyrolytic graphite in hydrogen partial pressure. A hint in the IR absorption spectrum at 2920 cm -1 provides an evidence for the incorporation of hydrogen in the film. Raman scattering (RS) measurements display a large downward shift in the position of the intense G line to 1500 cm-1, whereas the relatively weak D line is observed near 1350 cm-1 along with a strong enhancement in RS near 1210 and 800 cm-1. These features are attributed to an increased proportion of tetrahedral (sp3) character in the amorphous carbon network due to formation of hydrogen-related complexes. Additional support for this proposal is sought from the enhanced band gap of the PLD a-C:H films compared to those of unhydrogenated PLD a-C films.