2D Nucleation and Growth Phenomena in UPD of Cd on Ag(111) and Ag(100)

摘要

Two-dimensional (2D) nucleation and growth processes are observed in both the overpotential deposition (OPD) and the underpotential deposition (UPD) of metals. In the first case 2D nucleation and propagation of separate monolayers are involved in the electrochemical growth of quasi-perfect (screw dislocation free) crystal faces. This crystal growth mechanism has been elegantly demonstrated by Evgeni Budevski and his coworkers in the famous experiments performed on screw dislocation free Ag single crystal faces (1-3). In the case of UPD of metals 2D nucleation and growth phenomena are involved in the formation of condensed metal monolayers on foreign single crystal substrates (3,4). Therefore, the understanding of these phenomena is of great importance for the application of UPD processes for modification of surfaces with ultrathin films and heterostructures.