Graphitization of amorphous diamond-like carbon films by laser irradiation

Amorphous diamond-like hydrogenated carbon, or a-C:H, films were deposited on Si wafers by means of direct ion beam deposition from acetylene or from a gaseous mixture of acetylene and hydrogen. The samples were irradiated by the second harmonic (λ = 532 nm) of a Q-switched YAG:Nd laser. The effect of laser irradiation was studied with Raman and infrared spectroscopy and spectroscopic ellipsometry. Changes in the optical spectra of samples of various H content were investigated depending on laser intensity. Experimental data were interpreted taking into account the structural transformations of a-C:H films.