Ordering of monodisperse Ni nanoclusters by templating on high-temperature reconstructed alpha-Al2O3(0001).

We demonstrate that the characteristic [Formula in text] reconstructed surface of alpha-alumina (Al(2)O(3)) acts as a nanotemplate for the growth of well-ordered monodisperse arrays of Ni nanoclusters. Due to the insulating nature of the substrate we use dynamic scanning force microscopy operated in the non-contact mode (NC-AFM) to characterize the nanotemplate, to examine the size and distribution of metallic clusters on the surface and to investigate their position with respect to the surface atomic structure. The present NC-AFM results for the interaction of Ni with alpha-Al(2)O(3) are supported by density functional theory (DFT) calculations. The ability of alpha-Al(2)O(3)(0001) to act as a nanotemplate is attributed to a spatially modulated affinity towards the accommodation of Ni into the top layer by substituting the surface Al atoms at certain sites on the [Formula in text] reconstructed surface formed by high-temperature annealing. The insulating template, demonstrated for Al(2)O(3), may be a generally attractive system for the study of nanostructures which need to be isolated from a conducting bulk.