Step edge growth of Co nanoislands on Cu(111) surface

Abstract

Step edge growth of Co nanoislands on Cu(111) surface have been investigated by scanning tunneling microscopy (STM). The cobalt atoms cluster at the upper step edges and form bilayer islands of 2nm in diameter (about nine Co atoms in width) initially during the initial stage of Co deposition. This result is in accordance with the total energy calculations within density functional theory. Besides, the size and amount of nanoislands increase with increasing coverage. The average number of Co atoms contained in one island increases with a rate of 375 atoms per monolayer (ML). The statistics data on the STM images indicate that the cobalt nanoislands preferentially grow at the upper step edge during the first stage of Co deposition, then toward terrace, and finally, the growth rate of islands in edge is almost the same as that in terrace for Co thickness above 0.78–1.42 ML.