Characterization of nanocrystalline diamond films implanted with nitrogen ions

Nanocrystalline diamond films, prepared by a microwave plasma-enhanced CVD, were implanted using 110-keV nitrogen ions under fluence ranging from 10(1 6)-10(17) ions cm(-2). AFM, XRD, XPS and Raman spectroscopy were used to an alyze the changes in surface structure and chemical state of the films befo re and after implantation. Results show that high-fluence nitrogen ions imp lanted in the nanocrystalline diamond film cause a decline in diamond cryst allinity and a swelling of the crystal lattice; the cubic-shaped diamond gr ains in the film transform into similar roundish-shaped grains due to the s puttering effect of implanted nitrogen ions. Nitrogen-ion implantation chan ges the surface chemical state of the nanocrystalline diamond film. After h igh-fluence implantation, the surface of the film is completely covered by a layer of oxygen-containing groups. This phenomenon plays an importance ro le in the reduction of the adhesive friction between an Al2O3 ball and the nanocrystalline diamond film. (C) 2001 Elsevier Science B.V. All rights res erved.