Growth of Iridium and Silver on Ge(111) Studied by STM

We have used scanning tunneling microscopy (STM) to characterize the growth of iridium and silver onto Ge(111) as a function of coverage and annealing temperature. Ir was deposited onto the Ge(111) c(2x8) surface at different coverages less than 1ML. The Ir forms islands with a ($\surd $3x$\surd $3)R30\r{ } phase and island size increasing with increasing annealing temperature. Stranski-Krastanov growth was observed at most coverages. Ag deposited onto the Ge(111) c(2x8) surface and annealed at 450K forms both a (4x4) phase and a (3x1) phase. The Ge(111) surface reorganizes to a (2x2) phase after deposition of both Ir and Ag. High resolution images have been obtained allowing direct observation of the different phases.