Growth of monodispersed cobalt nanoparticles on 6H–SiC(0001) honeycomb template

We demonstrated an effective way of controlling the size dispersion of surface adsorbed nanoclusters by utilizing a reconstructed template with regular periodic porosity in the nanoscale range. Monodispersed cobalt (Co) nanoclusters of 3 nm sizes have been grown on the reconstructed 6H–SiC(0001) surface by electron-beam evaporation on the C-terminated 6∛×6∛R30° template at room temperature. In situ scanning tunneling microscopy was used to study the nucleation process of the Co nanoclusters on this template. We found that the average cluster size remains constant for different Co coverage, and the cluster density is linearly dependent on the coverage. The monodispersion of the cluster size is suggested to be due to the physical confinement of the Co clusters by the porous honeycomb structure of the SiC reconstructed surface. X-ray photoelectron spectroscopy reveals that the carbon-rich hexagon template prevents cobalt silicide formation up to an annealing temperature of 1150 °C.