Ag/Cu (0 0 1) electrodeposition: beyond the classical nucleation theory (original) (raw)
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Atomistic investigation of the Kolmogorov–Johnson–Mehl–Avrami law in electrodeposition process
Journal of Electroanalytical Chemistry, 2004
The electrosorption of Ag onto single-crystal copper (0 0 1) electrodes is studied by Monte Carlo (MC) simulations. An effective Ising model is employed with energetic parameters derived from N-body tight-binding interatomic potentials. Due to the attractive interactions between adsorbate atoms, the equilibrium isotherms present a first-order phase transition at sufficiently low temperatures. Using a dynamic MC algorithm, we study the kinetics of adsorption following sudden potential steps between the low and high branches of the isotherm. We compare these kinetics to those obtained within a mean-field approximation. The MC kinetics are dominated by nucleation and growth processes and are well described by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. We show how some improvements of the classical nucleation theory allow us to derive the physical quantities appearing in this equation, such as the nucleation and the growth rate, from the energetic parameters of the atomistic model.
Kinetic Monte Carlo simulation of electrodeposition of polycrystalline Cu
Electrochemistry Communications, 2009
ABSTRACT A two-dimensional cross-sectional poly-lattice kinetic Monte Carlo (2DCSP-KMC) model has been developed for simulation of the electrodeposition of polycrystalline copper on either a copper or gold substrate. The model has proved capable of capturing the effects of the deposition parameters, including the applied electrode potential, the concentration of Cu2+ ions and the temperature on the resultant deposit microstructure, the evolution of the grain density, the grain size, the variance of grain size and the grain boundary misorientation distribution. Three unit shapes namely the funnellike, columnar and pyramidal shapes, resulting from the competition between the growth of a grain and its neighbouring grains, are abstracted from a variety of morphology of individual grains to describe the effects of the deposition parameters on the deposit microstructure. The fundamentals of the dependence of these effects on substrate have been discussed and ascribed to the competition amongst the possible KMC events at each KMC step.
Model Calculations for Copper Clusters on Gold Electrodes
Using the embedded-atom method, the structure of small copper clusters on Au(111) electrodes has been investigated both by static and dynamic calculations. By varying the size of roughly circular clusters, the edge energy per atom is obtained; it agrees quite well with estimates based on experimental results. Small three-dimensional clusters tend to have the shape of a pyramid, whose sides are oriented in the directions of small surface energy. The presence of a cluster is found to distort the underlying lattice of adsorbed copper atoms.
Dynamical growth behavior of copper clusters during electrodeposition
Applied Physics Letters, 2010
Ultrahigh resolution full-field transmission x-ray microscopy enabled us to observe detailed phenomena during the potentiostatic copper electrodeposition on polycrystalline gold. We detected two coexisting cluster populations with different sizes. Their growth behaviors are different, with a shape transitions only occurring for large clusters. These differences influence the micromorphology and general properties of the overlayer.
Monte Carlo Simulation of Electrodeposition of Copper: A Multistep Free Energy Calculation
J. Phys. Chem. B, 2008
Simulation of copper electrodeposition on an initially flat surface by a classic two-step electron transfer sequence accompanied by surface diffusion was carried out by a three-dimensional ͑3-D͒ kinetic Monte Carlo model linked to a 1-D ͑continuum͒ finite difference model. The evolution of deposit roughness was simulated numerically and compared, through use of scaling parameters, with experimental data obtained by atomic force microscopy from deposits formed under constant potential in aqueous solutions of 0.5 M Cu 2 SO 4 and 1.0 M H 2 SO 4. The model was used to carry out parametric investigations on the effect of adsorption, surface diffusion, and lattice incorporation, all of which were found to exert an influence on the evolution of surface roughness.
Physical Review B, 1999
The soft deposition of copper and gold clusters on the Cu͑001͒ surface is studied by constant energy molecular-dynamics simulations. The atomic interactions are mimicked by a many-body potential based on the tight-binding model. The influence of cluster size, substrate temperature, and incident kinetic energy ͑in the low-energy limit͒ is analyzed. Some of the simulations are extended up to a few hundred picoseconds and within this simulation time the cluster flattens and partially spreads over the surface, and the degree of spreading depends on the above variables. The influence of surface steps has also been studied and the deposited atoms seem to have a strong affinity for step-edge sites. ͓S0163-1829͑99͒14227-9͔
Diffusion of Ag dimer on Cu (110) by dissociation-reassociation and concerted jump processes
2012 14th International Conference on Transparent Optical Networks (ICTON), 2012
In this work we investigate the diffusion of Ag dimer on Cu(110) surface by molecular dynamics simulation based on semi-empirical many-body potentials derived from the embedded atom method. The dissociationreassociation process is predicted to be dominant in static regime and this is confirmed by the dynamic investigation. A good agreement is found between static activation barrier and dynamic potential barrier.
Model calculations for copper clusters on Au(111) surfaces
Journal of Electroanalytical Chemistry, 2002
Using the embedded-atom method, the structure of small copper clusters on Au(111) electrodes has been investigated both by static and dynamic calculations. By varying the size of roughly circular clusters, the edge energy per atom is obtained; it agrees quite well with estimates based on experimental results. Small three-dimensional clusters tend to have the shape of a pyramid, whose sides are oriented in the directions of small surface energy. The presence of a cluster is found to distort the underlying lattice of adsorbed copper atoms.
A hybrid multiscale kinetic Monte Carlo method for simulation of copper electrodeposition
Journal of Computational Physics, 2008
A hybrid multiscale kinetic Monte Carlo (HMKMC) method for speeding up the simulation of copper electrodeposition is presented. The fast diffusion events are simulated deterministically with a heterogeneous diffusion model which considers site-blocking effects of additives. Chemical reactions are simulated by an accelerated (tau-leaping) method for discrete stochastic simulation which adaptively selects exact discrete stochastic simulation for the appropriate reaction whenever that is necessary. The HMKMC method is seen to be accurate and highly efficient.
Growth patterns in electrodeposition
Physica A: Statistical Mechanics and its Applications, 1999
In that short review of growth processes in electrodeposition, we aim at discussing the relevant physical and chemical mechanisms which are likely to influence the dynamics of these growth processes and the morphology of the electrodeposits obtained in thin gap geometries. Electrodeposition has been early recognized as a paradigm experiment for reproducing diffusion-limited aggregation (DLA) morphologies as produced by the model of Witten and Sanders. The obvious similitude between DLA clusters and thin gap electrodeposits for some parameter values opened some fundamental issues about the correspondence of these experimental systems with DLA processes. We want to address in this paper the greater complexity of an electrodeposition process, in particular as fax as the interfacial chemical and electrochemical kinetics is concerned. Our discussion is illustrated by an experimental analysis of copper electrodeposition in thin gap cells, based on interferometric, spectroscopic and optical inspection of both the deposit morphology and its composition and of the concentration fields around the deposit. Supported by these experimental investigations of copper electrodeposition in thin gap cells, we show that chemistry based argumentations are unescapable to explain the observed dynamical processes.