Scanning tunnelling microscopy was used to study the Ostwald ripening of 2-dimensional Cu islands on Cu (001). The ripening mechanisms were characterized by considering the time dependence of the sizes of individual islands. The unexpected result, for a simple metal surface, was that the flow of atoms from one island to another was limited by the attachment-detachment kinetics at the island edges. In order to explain this result, it was proposed that the transport of atoms between islands occurred via vacancy rather than adatom diffusion.

Surface Self-Diffusion by Vacancy Motion: Island Ripening on Cu (001) J.B.Hannon, C.Klünker, M.Giesen, H.Ibach, N.C.Bartelt, J.C.Hamilton: Physical Review Letters, 1997, 79[13], 2506-9