ATOMIC STRUCTURES AND GROWTH MECHANISMS OF ELECTRODEPOSITED AG AND TEFILMS AS DISCERNED BY ATOMIC-FORCE MICROSCOPY

We have investigated atomic structures as well as growth morphologies of electrodeposited thin Ag and Te films on Au(100) under an aqueous s ulfuric acid solution. The extremely flat Ag films were formed by an i deal Frank-van der Merwe mode even at a high deposition rate [similar to 7.2 monolayer (ML)/min], which suggests that the surface diffusion process of Ag adatoms is extremely rapid. In the underpotentially depo sited Te on Au(100), the (root 2x root 2)R45 degrees-Te structure (cov erage, theta=0.5) for a first monolayer was formed through the (2X2)-T e structure (theta=0.25) under an aqueous H2SO4 solution. In contrast with the Ag films, the bulk deposited Te films were formed by a Strans ki-Krastanov mode even at a low deposition rate (similar to 0.5 ML/min ), which suggests that the surface diffusion process of Te adatoms is extremely slow. The Te(1010) films (>80 ML) were grown on Au(100) thro ugh the c(root 2x3 root 2)R45 degrees (20-30 ML) and (root 2x root 2)R 45 degrees-Te(<10 ML) structures. (C) 1996 American Vacuum Society.