A self-terminating rapid electrodeposition process for controlled growth of platinum (Pt) monolayer films from a K(2)PtCl(4)-NaCl electrolyte has been developed that is tantamount to wet atomic layer deposition. Despite the deposition overpotential being in excess of 1 volt, Pt deposition was quenched at potentials just negative of proton reduction by an alteration of the double-layer structure induced by a saturated surface coverage of underpotential deposited H (H(upd)). The surface was reactivated for further Pt deposition by stepping the potential to more positive values, where H(upd) is oxidized and fresh sites for the adsorption of PtCl(4)(2-) become available. Periodic pulsing of the potential enables sequential deposition of two-dimensional Pt layers to fabricate films of desired thickness, relevant to a range of advanced technologies.

In situ stress measurements were made during copper electrodeposition onto ͑111͒-textured Au from acidic sulfate electrolyte using the wafer curvature method. In the Cu underpotential deposition region, the intermediate (ͱ3 ϫ ͱ3)R30°Cu-sulfate honeycomb structure creates a surface stress that is tensile when compared to that of the sulfate-adsorbed electrode at positive potentials or the complete (1 ϫ 1) Cu monolayer at more negative potentials. This behavior is consistent with surface-induced charge redistribution models that appear in the literature. During the bulk deposition of Cu, there is a rapid increase in tensile stress during the first 20 nm of growth that we attribute to nuclei coalescence and grain boundary formation. The magnitude of the tensile stress as well as the film thickness at which the maximum stress occurs are both dependent upon the electrode potential due to its influence on the nucleation density. When the films are continuous, the total stress is the superposition of the coalescence-induced tensile stress and a compressive stress which we attribute to the incorporation of mobile adatoms on the surface into the grain boundaries. The tensile stress component dominates thin films deposited at high overpotential, whereas thick films deposited at low overpotential have a net compressive stress. When deposition is interrupted both tensile and compressive components of the stress relax somewhat but are quickly reestablished when deposition is resumed. The development of the growth stress that we describe here is very similar to that which has been reported for Cu deposition from the vapor phase.

The measurement of current and voltage fluctuations on the same electrochemical cell allows the evaluation of a quantity R n known as noise resistance, which has been proposed as an indication of the corrosion resistance of the material under study. The theoretical basis for the relationship between R n and the electrode impedance Z is developed, taking into account the various measurement schemes currently in use. Parameters such as cell geometry, solution resistance, and electrodes with different kinetics are considered. It is shown that, in general, the modulus of the electrode impedance can be derived by measuring the power spectral densities (PSD) of the voltage and current noises. The circumstances in which R n is equal to the polarization resistance of the electrode are also discussed.