Structural control of carbon nickel nano-composite thin films without substrate heating

• Metal–carbon films were grown at room temperature by ionised sputter deposition.
• We demonstrate growth of nickel nanoparticles surrounded by ordered graphitic layers.
• Substrate biasing can be used to control the phase and ordering of these structures.
• Structural control without heating allows growth on temperature sensitive substrates.

A variety of characterization techniques have been employed to study the growth and structure of carbon nickel thin films fabricated by ionised magnetron sputter deposition. A two target magnetron system is used along with an RF powered coil to create a secondary plasma, with a DC bias applied at the substrate. By varying the substrate bias it is possible to control the flux and energy of the depositing species and therefore the resulting film microstructure. Films typically consist of nickel-based nano-particles within a carbon matrix. It has been observed that a change between the metastable hexagonal structure of nickel and the stable face centred cubic phase can be induced. This change in metal crystallinity is accompanied by a change in carbon ordering. The ability to control the film structure and morphology without the need for post-deposition heat treatments opens up the possibility of depositing a range of structures onto temperature sensitive substrates such as polymers.