Abstract
The evolution of Cu crystal surfaces in an aqueous perchloric acid solution at both null (j=0) and constant anodic apparent current density (j=6 mu A cm(-2)) at room temperature was followed by in situ scanning tunneling microscopy sequential imaging. For j=0, the Cu surface turns out to be highly dynamic as terrace growth, step displacement, and smoothening of small pits can be observed. These processes lead to a small decrease in the value of the root-mean-square roughness (xi). On the other hand, for j=6 mu A cm(-2), an inhomogeneous attack proceeds with a marked increase in xi. In this case, while some surface domains become progressively rough others develop nm-sized etched pits that turn the interface unstable. The evolution of the Cu topography under the experimental conditions of this work was simulated using a Monte Carlo algorithm based on a dissolution model in which surface processes are influenced by inhomogeneity stabilizing cavities.