Controlled epitaxial growth of Cu and Ni islands on oxygen-preadsorbed Cu(100) surfaces

Abstract

Growth of Cu and Ni islands was studied on the two oxygen-preadsorbed Cu(100) surfaces, a Cu(100) surface covered with nanometer size c(2×2)–O domains and a reconstructed (2 2 × 2 )R45°Cu(100)–O surface. Preadsorbed oxygen on Cu(100) migrates onto the epitaxially grown metal islands. Homoepitaxial growth of Cu on a nanometer-size c(2×2)–O Cu(100) surface forms monolayered rectangular Cu islands which grow in the [010] and [001] directions, where the island takes an anisotropic (2 2 × 2 )R45°–O structure. In contrast, Ni atoms grow in no specific orientation on the nanometer-size c(2×2)–O Cu(100) surface and the Ni islands take a c(2×2)–O structure. Contrary to this, Ni atoms deposited on the reconstructed (2 2 × 2 )R45°Cu(100)–O surface undergo specific nucleation along the Ni rows paved in Cu-missed troughs on the (2 2 × 2 )R45°Cu(100)–O surface and Ni wire of nanometer width grows along the [001] or [010] direction. The shape of epitaxial islands may be governed in an energetically feasible fashion influenced by the adsorption of oxygen, but the nanometer-width Ni wire is the result of the kinetic feasibility of the specific nucleation.