RECONSTRUCTION-DETERMINED GROWTH OF SILVER ON SILICON(111)-(7x7)

摘要

The heteroepitaxial growth of Ag on Si(111)-(7x7) is strongly affected by the surface reconstruction, which introduces additional constraints into the motion of deposited atoms. To characterize the processes and parameters crucial for growth, we study Ag/Si(111)-(7x7) heteroepi-taxy from nucleation up to coverages of a few monolayers. The experimental results obtained by scanning tunneling microscopy are interpreted using a coarse-grained kinetic Monte Carlo model. The attempt frequency and the barrier to hopping of a single Ag atom between half-unit cells (HUCs) are estimated. From our experiments and simulations we infer the existence of a non-thermal post-deposition mobility of Ag atoms and a stable configuration of 6 Ag atoms in a HUC. The morphology of the wetting layer and the three-dimensional island density during further Stranski-Krastanov growth at various temperatures are discussed.