INITIAL-STAGE OF THE ELECTRODEPOSITION OF AG ON AU(100) OBSERVED BY IN-SITU ATOMIC-FORCE MICROSCOPY

We have investigated atomic structures as well as growth morphologies of thin Ag films on Au(100) under acidic solutions by an in-situ AFM. In the UPD region, the pseudomorphic (1 x 1)-Ag layer for a first mono layer is formed through the c(root 2 x 5 root 2)R45 degrees-Ag structu re (coverage, theta=0.6) in both HClO4 and H2SO4 solutions. In the bul k deposition region, the Ag films are formed by an ideal layer-by-laye r growth mode (Frank-Van der Merwe mode) even at a high deposition rat e (similar to 7.2 ML/min), which suggests that the surface diffusion p rocess of Ag adatoms is extremely rapid. Noteworthy is that the prefer ential Ag deposition at regions with higher step densities or imperfec tions resulted in the extremely flat Ag films.