Electrodeposition definition

Cu9ln4 and Cu2Se. They performed electrodeposition potentiostatically at room temperature on Ti or Ni rotating disk electrodes from acidic, citrate-buffered solutions. It was shown that the formation of crystalline definite compounds is correlated with a slow surface process, which induced a plateau on the polarization curves. The use of citrate ions was found to shift the copper deposition potential in the negative direction, lower the plateau current, and slow down the interfacial reactions. 

Electrochemistry provides routes to directly prepare nanostructures both delocalized in a random or organized way and localized at predefined surface sites with adjustable aspect ratios. Purity, monodispersity, ligation, and other chemical properties and treatments are definitely important in most cases. By delocalized electrodeposition it is possible to decorate large areas of metal or semiconductor surfaces with structures of a narrow size distribution stable nuclei-clusters can be... 

The electrodeposition of an alloy requires, by definition, the codeposition of two or more metals. In other words, their ions must be present in an electrolyte that provides a cathode film, where the individual deposition potentials can be made to be close or even the same. Figure ll.l depicts typical polarization curves, that is, deposition... 

The current density can, as a rule, be controlled by the plater. It determines the CE and/or whether deposition will take place at all. The definition of current density in terms of electrodeposition as given above yields an average figure of little use in most cases. A more accurate, useful, and immediate definition is given as... 

The region near the electrode where the concentration of a species differs from that of its bulk value is referred to as the diffusion layer. The boundary between that region and the bulk of the bath is, naturally, not sharp. By definition, however, the region in which the concentration of a particular species differs from its bulk concentration by 1% is the diffusion layer. Figure 18.5 depicts the metal ion concentration near a cathode during electrodeposition. 

InSb is a direct semiconductor, and quantum dots of InSb, made under ultra-high vacuum conditions, have already been successfully studied for laser appHcations [32]. Quantum dots are widely under investigation nowadays and this is a rapidly growing research field. Definite electrodeposition from ionic Hquids would be an important contribution. 

O Brien. 1235 Ohmic drop, 811, 1089, 1108 Ohmic resistance, 1175 Ohm s law, 1127. 1172 Open circuit cell, 1350 Open circuit decay method, 1412 Order of electrodic reaction, definition 1187. 1188 cathodic reaction, 1188 anodic reaction, 1188 Organic adsorption. 968. 978. 1339 additives, electrodeposition, 1339 aliphatic molecules, 978, 979 and the almost-null current test. 971 aromatic compounds, 979 charge transfer reaction, 969, 970 chemical potential, 975 as corrosion inhibitors, 968, 1192 electrode properties and, 979 electrolyte properties and, 979 forces involved in, 971, 972 977, 978 free energy, 971 functional groups in, 979 heterogeneity of the electrode, 983, 1195 hydrocarbon chains, 978, 979 hydrogen coadsorption and, 1340 hydrophilicity and, 982 importance, 968 and industrial processes, 968 irreversible. 969. 970 isotherms and, 982, 983... 

Semiconductors (cont.) equilibrium in. 1076 exponential law, 1081 germanium as, properties, 1076 hole movement 1076 impedance of, 1136 importance of, 785 limiting current 1088 n-, in thermal reactions, 1086 n-pjunction, 1073, 1081 p- in thermal reactions. 1086 photoactivity of, 1089 photoelec trochemistiy, 1073 photos timulated electrodeposition on. 1345 potential variation with distance in, 1082 silicon as, properties, 1076 surface states. 1086 symmetry factor in, 1082 thermal reactions, definition, 1088 Sen, 1495... 

Stanski, electrodeposition, 1301,1303 Standard hydrogen electrode, 1108 see also hydrogen electrode potential, definition, 840, 1060, 1061 Steady state, 1147, 1212 current, 1248... 

Transfer reaction, electrodeposition. 1310 Transients, 1119, 1401, 1417, 1422 definition, 850 diffusion current, 1404 electrode surface area using, 1403... 

Variants of preparation have been proposed [135, 248] including sintering [391] or co-electrodeposition of the precursors [138, 407], and aluminization of the surface of Ni at high temperature whose nature has a definite effect on the resulting electrocatalytic activity [408]. The main features of Raney Ni have been evaluated, including the pore size distribution and the real surface area [93, 135]. It has been found that the composition of the precursor alloys and their particle size have important influence on the adsorption properties of the resulting Raney metal, hence on its electrocatalytic properties [409]. 

Tellurium is a constituent common to several definite compounds having semiconducting properties which can be obtained by electrolytic deposition (e.g. CdTe, ZnTe,...). The low solubility of tellurium oxide in acidic aqueous solutions explains why its kinetics of electrodeposition, in the binary of tertiary alloys involved, is mainly controlled by mass transport. 

Electrodeposition could be a pseudo-S-L type process, although definitive proof is lacking. The element to be ionized, uranium [16] or plutonium [17], is coelec-trodeposited with a platinum metal layer, then covered with an additional layer of platinum. The U or Pu is believed to be electrodeposited as an oxide, and platinum is electrodeposited as the metal. Hence there is thought to be a U or Pu oxide buried in the metal matrix. When this deposit is heated, after a sufficient length of time atomic cations of U or Pu begin to sublime from the surface without measurable metal oxide ions. Metal oxide ions should be readily observable if they are present in the matrix. Thermodynamic calculations indicate that the hot platinum matrix will not reduce the U and Pu oxides to the metallic state, and yet the observed species are atomic ions and not oxide molecular ions. 

On the other hand when electrolyzing an aqueous solution of zinc sulphate we observe not only deposition of zinc at the cathode but also liberation of a certain amount of hydrogen so that the yield of zinc is less than would correspond to 100 p. c. current efficiency. When, however, the equivalents of deposited zinc and liberated hydrogen are added together, the current efficiency is 100 per cent. Nevertheless when speaking of current efficiency we always bear in mind a definite production, electrodeposition of zinc for instance, while the quantity of current required for the liberation of the hydrogen is considered to be a loss. 

According to the definition of Brenner [43], it has become common to classify electrolytic metal deposition from nonaqueous electrolytes according to two groups, i. e., aqueous and nonaqueous . The aqueous group comprises all electrolyte systems from which metals or metallic alloys are deposited that can also be deposited from aqueous solutions. The nonaqueous group includes systems from which metals or metal alloys can be electrodeposited that cannot be plated from aqueous electrolytes. 

Dendritic deposits grow under mass transport-controlled electrodeposition conditions. These conditions involve low concentration of electrolyte and high current density. A dendrite is a skeleton of a monocrystal consisting of stem and branches. The shapes of the dendrites are mainly determined by the directions of preferred growth in the lattice. The simplest dendrites consist of the stem and primary branches. The primary branches may develop secondary and tertiary branches. The angles between the stem and the branches, or between different branches, assume certain definite values in accordance with the space lattice. Thus, dendrites can be two dimensional (2D) or three dimensional (3D). 

Figure 1 Definition of superfilling based on rate of copper electrodeposition along the feature sidewall. 

The stoichiometry of the film depends upon the solute concentration, the pH of the electrolyte, electrolysis current density, and deposition time. A careful analysis of the electrodeposition potential curve appears to be the best way to determine the ideal experimental conditions for the preparation of various definite compounds like CuInSe2 by electrolyhc co-deposition. 

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