Carbon nitride films prepared by excimer laser ablation

The preparation of carbon nitride films by laser ablation of graphite in ammonia atmosphere is reported. Experiments were performed at room temperature under different NH3 total pressures using an ArF excimer laser (193 nm). The films were deposited on silicon and metal substrates from the ablated carbon radicals and the species generated by the ammonia photodissociation under the laser VUV photons. Profilometry and ellipsometry show an evolution of the growth rate and refractive index. Energy dispersive X-ray and Fourier transform infrared spectroscopies reveal a gradual incorporation of nitrogen in the films for increasing ammonia concentration. Furthermore, infrared spectra show the presence of C=N and C-N groups and the incorporation of hydrogen bonded to carbon and nitrogen. These observations were corroborated by Raman spectroscopy and hydrogen effusion.