Structure and properties of a-C:N films prepared by pulsed excimer laser deposition

We present results on the synthesis of a-C:N films deposited by pulsed excimer laser ablation of graphite in a nitrogen gas ambient. Analysis with RBS and forward recoil spectrometry show that the films are hydrogen-free and nitrogen can be incorporated up to 40% by varying the nitrogen gas pressure. Electron microscopy has identified these films to be amorphous. Raman spectroscopy, infrared spectroscopy, and electron energy loss spectroscopy have revealed carbon-nitrogen bonding structures. Compared to a-diamond films prepared by the same technique, the C:N films still possess the properties of high mechanical hardness, chemically inertness and good wear resistance, but incorporation of nitrogen into the films generally degrades their diamond-like properties. The results suggest that nitrogen doping effect is resulted in the films under the present process, instead of carbon-nitrogen compound formation.