Rayleigh-instability-driven simultaneous morphological and compositional transformation from Co nanowires to CoO octahedra

Arrays of regularly distributed CoO nano-octahedra are obtained by annealing Co nanowires at high temperatures. Both the size and the separation distance of the nano-octahedra can be controlled by tuning the annealing temperature. These self-assembled linear arrays of CoO nanocrystals result from the synergetic combination of the morphological transformation due to the intrinsic Rayleigh instability and the phase transformation due to the cobalt oxidation. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3518470]