The evolution of CO adsorption on Cu(111) as studied with bare and CO-functionalized scanning tunneling tips

CO adlayers on Cu(111) are studied using scanning tunneling microscopy with special attention to the role of functionalized tips prepared by vertical manipulation An attractive adsorbate-adsorbate interaction is found already at ultra-low coverage using lateral manipulation. Increasing the coverage leads to island formation facilitated by a lowering of the diffusion barrie r. At 1/3 ML coverage the root 3 x root 3R30 degrees phase can be visualize d clearly with GO-functionalized tips. Images obtained at CO saturation exh ibit a 4 x 4 supercell of the adlayer as the basis structural element. (C) 1999 Elsevier Science B.V. All rights reserved.