Reconstruction determined submonolayer growth of Ag on Si(1 1 1)-(7×7) surface

The submonolayer growth of Ag on Si(1 1 1)-(7×7) surface at temperatures from 420 to 540 K was studied. Island densities, size distributions and average number of Ag atoms per occupied half-unit cell (HUC) of 7×7 reconstruction were investigated. At higher coverage large 2D islands with jagged shapes were observed. A scenario of the growth was outlined, based on the assumptions of existence of saturated Ag islands on the surface which cannot overgrow HUC boundaries by adatom capture. Such a model explains morphology of the large islands as well as the presence of the large amount of small islands formed inside HUCs. The capacity of a single HUC was found to be ≈18 Ag atoms and the capacity of HUCs covered by the large islands was found to be ≈31 Ag atoms on average.