| Abstract: | By using scanning tunnelling microscopy and spectroscopy we have studied condensation of Cu and Ag on Si(111)7×7 between room temperature and 130°C in the submonolayer and monolayer range. For submonolayer coverage, both metals develop regular clusters on top of the inner adatoms of 7×7 unit cell halves, which we assign to the initial nuclei of metal condensation. The metal film growth continues by adding further metal atoms to these clusters until one half of the 7×7 unit cell is covered completely with a triangular 2-D metal island. For a coverage of three monolayers neither Cu nor Ag grows in a layer-by-layer mode. Characteristic differences observed for both metals may be explained by the more reactive nature of Cu. |
