Potential-controlled step flow to 3D step decoration transition: Ni electrodeposition on Ag(111)

A novel growth effect, the potential-controlled transition from 2D step-few growth (-0.69 V-Ag/AgCl) to (i) selective growth of 3D admetal islands at substrate steps (-0.73 V) and (ii) 3D island growth on-steps and substrate terraces (-0.85 V), is demonstrated for Ni electrodeposition on Ag(lll). The nucleation and growth process apparently proceeds via direct deposition from the solution at step sites and can be rationalized by a kinetically controlled multilayer growth process, where the higher layer nucleation rate increases more with overpotential than does the 2D growth rate.