Microstructure and optical properties of cobalt–carbon nanocomposites prepared by RF-sputtering

Cobalt/carbon nanocomposite coating (Co NPs @ a-C: H), which consist of cobalt nanoparticles buried in hydrogenated amorphous carbon are prepared by RF-sputtering and RF-plasma enhanced chemical vapor deposition on silicon substrates. In these processes, the coatings are produced from a cobalt sputtered target and acetylene reactant gas. The crystalline structure and surface topography of the deposited films are characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The AFM shows that the average size distribution depends on the deposition conditions and RMS varies from 3.5 up to 6 nm. The XRD analyses indicate the presence of cobalt nanostructure as centered face cubic phase and its oxide, but with no evidence of carbide structure. The energy-dispersive X-ray spectroscopy analysis was used to identify the elements composition in the films and the ultraviolet–visible spectrophotometry is used to study surface plasmon resonance bands of Co nanoparticles.