Electrodeposition growth mechanisms

Although the mechanisms discussed above are still topics of debate, it is now firmly established that the electrodeposition of conducting polymers proceeds via some kind of nucleation and phase-growth mechanism, akin to the electrodeposition of metals.56,72-74 Both cyclic voltammetry and potential step techniques have been widely used to investigate these processes, and the electrochemical observations have been supported by various types of spectroscopy62,75-78 and microscopy.78-80... 

G6mez H, Henriquez R, Schrebler R, Cordova R, Ramirez D, Riveros G, Dalchiele EA (2005) Electrodeposition of CdTe thin films onto n-Si(lOO) nucleation and growth mechanisms. Electrochim Acta 50 1299-1305... 

Tanabe and Kamasaki (52) observed the nucleation growth mechanism in the deposition of Au on Fe(OOl) and Fe(l 10) single crystals. The population of nuclei (TDCs) of Au electrodeposited in the initial stages of deposition was 3 X 10 cm . In further deposition, micro-TDCs were connected one to another forming a network structure. Stable coherent deposits of Au were formed when the surface coverage was about 80%. 

Trejo etal. [225, 226] have also investigated the influence of several ethoxylated additives (ethyleneglycol and PEG polymers of different molecular weights) on the nucleation, growth mechanism, and morphology of zinc electrodeposited on GG from an acidic chloride bath. Results have shown that the presence of additives modifies the nucleation process and determines the properties of the deposits. 

Properties of thin layers of lead electrodeposited on vitreous carbon have been found identical with that of metallic lead [304]. Therefore Pb and Pb02 coated reticulated vitreous carbon (RVC) electrodes [185] can be applied as electrodes in lead-acid batteries, as reviewed in [305]. The deposition of lead on carbon is through the diffusion-controlled process with instantaneous or progressive nucleation, for high and low Pb + concentration, respectively, and three-dimensional growth mechanism. The number of nucleation sites increases with deposition overpotential, as shown for vitreous [306] and glassy carbon [307] electrodes. The concentration dependence of the nucleation... 

Electrodeposition on boron-doped diamond has pointed to progressive growth mechanism, as confirmed by chronoam-perometric transients and ex situ AFM images [ 312]. At lower concentrations, lead ions are deposited directly on the diamond substrate, while at higher concentrations, deposits overlap and further deposition occurs on lead. At higher temperatures, the size of the nuclei is bigger. 

Schrebler et al. studied the nucleation and growth mechanisms for Re deposition on polyerystalline Au electrodes, from a bath containing 0.75 mM perrhenic acid and 0.1 M sodium sulfate at pH = 2. The potentiostatic step technique was simultaneously employed with measurements of mass changes in an electrochemical quartz-crystal microbalance. The mass vs. time transients were fitted with equations deduced from the current versus time relationships of the conventional nucleation and growth models. It was concluded that electrodeposition of Re started with progressive nucleation and two-dimensional growth, followed by two other contributions ... 

It was proposed by Andricacos et al This mechanism considers one-additive system. It is noted in Ref. 47 (Ch. 10, Sections 10.4 and 10.5) that in general, adsorption of additives (inhibitor) at the cathode affects the kinetics and growth mechanism of electrodeposition. The surface coverage of the additive (inhibitor), 0, is a function of the diffusion controlled rates of the adsorption-desorption processes. In the differential-inhibition mechanism it is assumed that a very wide range of additive fluxes over the micro-profile (vias and trenches) exists, that is, extremely low flux in deep interior comers, low flux at the bottom center, moderate flux at the sidewalls, and high flux at shoulders. 

The growth mechanism of in situ deposited films proposed by Stejskal and coworkers210 has similarities to that described earlier for electrodeposited PAn. It is important to note that the in situ method produces both a surface coating as well as the normal powdery precipitate from the bulk of the solution. It is proposed by... 

In the E/C synthesis, the first step in which metal nanocrystals are deposited on the substrate is critical. The semiconductor particles grow from the metal particles on a particle-by-particle basis (i.e. each metal particle is chemically transformed to the corresponding semiconductor). The size and size distribution, therefore, in the first step determine the final size of the semiconductor particles. For that reason, it is important to achieve an understanding of the growth mechanism of the metal nanocrystal deposition. Penner and associates studied the electrodeposition of various metal nanoparticles (Ag, Pt, Zn, Cu, Cd) mainly onto basal plane-oriented graphite and also onto Si electrodes [6-11]. The depositions were carried out from dilute aqueous solutions of metal ions using a potentiostatic pulse regime. A short (typically tens of ms) potential pulse was applied followed by open[Pg.174]

This creates nucleation sites randomly distributed on the electrode surface (Pt, ITO, Au, etc.). Then, the nucleus size increases and the nuclei coalesce. In the first stage of the nucleation process, the contribution of a two-dimensional nucleation is important, indicating that the polymeric deposit initiates by the formation of a two-dimensional film. At longer times, upper structures appear which corroborates a three-dimensional growth. This 2D and 3D nucleation and growth mechanism (NGM) of PTh and PPy has been extensively studied by different techniques [22-24] and presents similarities with the electrodeposition of metals [25, 26]. As a result, thin films (<1 pm) are compact and smooth in morphology (due to a two-... 

Jovic VD, Maksimovic VM, Pavlovic MG, Popov KI (2006) Morphology, internal structure and growth mechanism of electrodeposited Ni and Co powders. J Solid State Electrochem... 

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