An in Situ Stm Study of Cu and Ni Electrodeposition

Publisher Website
Google Scholar
Abstract
An STM study has been initiated to investigate the various processes associated with electrodeposition of Cu-Ni multilayers on Cu (100). The substrates were prepared by electropolishing in phosphoric acid followed by immersion in 10 mmol/l HCl. A (√2×√) R°45 adlattice of oxidatively adsorbed chlorine is formed under these conditions. The adlayer stabilizes the surface steps in the 〈100〉 direction which corresponds to the close packed direction of the chloride adlattice. In dilute mmo1/1 solutions of cuprous ion, reduction occurs under mass transport control with the electrocrystallization reaction proceeding by step flow in the 〈100〉 direction. At more negative potentials chloride is reductively desorbed. Coincident with desorption the highly kinked metal steps become frizzy and move towards adopting the close packed 〈110〉 orientation of the metal lattice. Preliminary experiments on heteroepitaxial nickel deposition reveal regions where electrocrystallization on Cu(100) occurs via step flow in the 〈110〉 direction.