Nanostructuring of C:Ni nanocomposite films using ion-beam assisted ion-beam co-sputtering

The effect of the assisting low energy ion beam on the structure of nanocomposite thin films is studied for the carbon:nickel system. The parameter range for the ion beam assisted deposition (IBAD) comprised (i) growth temperatures from room temperature to 500°C, (ii) assisting Ar ion energies from 50 eV to 140 eV, and (iii) nickel concentrations from 5 at.% to 40 at.%. Atomic composition of the films was determined by ion beam analysis. The phase structure of the C:Ni thin films was analysed by Raman spectroscopy and X-Ray diffraction. Scanning electron microscopy was applied for surface analysis, and high resolution transmission electron microscopy was used for microstructure determination. The growth of C:Ni nanocomposites without ion assistance is controlled by the phase separation under kinetic constraints of surface and volume diffusion and the film growth rate. In contrast, ordered nanostructures are formed upon utilizing the energy and momentum input of the assisting ion beam. They consist of nanocolumns with varying tilt angles in relation to the film surface, compositionally modulated surface ripples or three-dimensionally ordered nanopatterns throughout the entire thin film thickness. The correlation between IBAD parameters (temperature, ion energy and flux) and nanocomposite morphological and microstructural features (phase structure, tilting angle, and periodicity) will be presented.