Raman spectroscopy study of the carbon structure of a-C:(H, Cu) and a-C:(H, Co) composite films

The main changes induced in the Raman spectrum of a -C:H films in the 1200-to 1700-cm −1 frequency region by modification with Cu and Co are ascertained. A comparison of the results obtained with the available data on various carbon structures reveals that the introduction of metals in concentrations comparable to the carbon content stimulates growth and ordering of graphite-like nanoclusters in the sp 2 carbon bonding system. It is found that, while similar structural rearrangements occur under thermal annealing of both a -C:H and composite a -C:(H, Cu) and a -C:(H, Co) films, the presence of metals interferes with thermally stimulated graphitization. The size of the graphite-like nanoclusters in annealed and unannealed films of all types is estimated, and Co is shown to produce a more efficient graphitizing effect than Cu.