Self-organized growth of Ni nanoparticles on a cobalt-oxide thin film induced by a buried misfit dislocation network

We report on a clear tendency toward organized growth, at room temperature, of Ni nanoislands deposited on a CoO(001) nanopatterned surface. The 9.2 nm square surface patterning consists in a periodic displacement field induced at the surface by an underlying interfacial dislocations network that is buried at the interface between the 5 nm thick CoO(001) thin film and the Ag(001) substrate. Grazing incidence small and wide angle x-ray scattering (GISAXS and GIXD) performed in situ, during growth, reveal that the nucleation of Ni particles is driven by the underlaying dislocation distribution. The tendency for organization is confirmed by scanning tunneling microscopy (STM), which also reveals a quite narrow size distribution of the Ni nanoparticles around 5 nm width and 0.6 nm height.