Electrodeposition parameters

Electrodeposition is a unique, versatile technique for fabrication of metal oxide, polymer, and composite electrodes for electrochemical supercapacitors. Composition, crystal structure, and morphology of the deposits can be easily manipulated by adjusting the electrodeposition parameters to achieve improved capacitive behavior. Current progress, however, is far from the commercial expectations for electrochemical supercapacitors. 

Table 1.2 Chemical composition and electrodeposition parameters for each layer of the Cu/ Sn/Cu/Zn precursor. Potentials are given with respect to the AgjAgCl reference electrode.

Hamlaoui Y, Tifouti L, RemazeiUes C, Pedraza F. Cathodic electrodeposition of cerium based oxides on carbon steel from concentrated cerium nitrate. Part II Influence of electrodeposition parameters and of the addition of PEG. Mater. Chem. Phys. 2010 120 172-180. DOI 10.1016/j.matchemphys.2009.10.042. 

The electrodeposition of Cr in acidic chloroaluminates was investigated in [24]. The authors report that the Cr content in the AlCr deposit can vary from 0 to 94 mol %, depending on the deposition parameters. The deposit consists both of Cr-rich and Al-rich solid solutions as well as intermetallic compounds. An interesting feature of these deposits is their high-temperature oxidation resistance, the layers seeming to withstand temperatures of up to 800 °C, so coatings with such an alloy could have interesting applications. 

The anionic composition of the cathodic product is not the only parameter that can be controlled through electrolysis conditions. Grinevitch et al. [559] reported on the investigation of the co-deposition of tantalum and niobium during the electrolysis of fluoride - chloride melts. Appropriate electrodeposition conditions were found that enable to obtain either pure niobium or alloys. 

Given the thermodynamic properties of a system, judicious variation of the different plating parameters to assist in manufacturing the desired electrodeposit should be based on an accurate kinetic model. Engelken and Van Doren [6, 7] proposed... 

If the electrolysis parameters (precursor concentrations, pH, temperature, cur-rent/potential, substrate) be defined in a precise manner, a self-regulated growth of the compound can be established, and highly (111 )-oriented zinc blende (ZB) deposits up to several p,m thickness are obtained at potentials lying at the anodic limit of the diffusion range (Fig. 3.3) [60]. Currently, the typical method of cathodic electrodeposition has been developed to yield quite compact and coherent, polycrystalline, ZB n-CdSe films of well-defined stoichiometry. The intensity of the preferred ZB(f 11) orientation obtained with as-deposited CdSe/Ni samples has been quite high [61]. 

Similarly, the (111) GaAs substrate could be used to achieve epitaxial growth of zinc blende CdSe by electrodeposition from the standard acidic aqueous solution [7]. It was shown that the large lattice mismatch between CdSe and GaAs (7.4%) is accommodated mainly by interfacial dislocations and results in the formation of a high density of twins or stacking faults in the CdSe structure. Epitaxy declined rapidly on increasing the layer thickness or when the experimental parameters were not optimal. 

Photovoltaic response parameters for electrodeposited (polycrystalline) CdTe thin film electrodes in sulfide-polysulfide or alkaline sodium telluride PEC have been reported, primarily with no reference to the stability of the cells [100], In view of the instability of CdTe in aqueous solutions, Bhattacharya and Rajeshwar [101] employed two methods for the characterization of their electrodeposited CdTe-based PEC. In the first one, a coating of Pb02 (-100 nm thick) was deposited on the CdTe film surface by electroless deposition, and the coated films... 

Gutierrez MT, Salvador P (1987) Photoelectrochemical characterization and optimization of a liquid-junction photovoltaic cell based on electrodeposited CdSe thin films Influence of anneaUng and photoetching on the physical parameters determining the cell performance. Sol Energy Mater 15 99-113... 

To deposit Au structures, a Au probe is approached to the surface until a positive feedback is observed. This is due to the regeneration of Cl species on the substrate while Au is deposited from AUCI4 according to the reverse reaction, leading to an increase in the local concentration of Cl. The microelectrode is then left at this position above the substrate for a certain time, after which it is withdrawn from the surface. The potential of the substrate, the electrolyte, and the pH were found to be the most significant parameters determining in determining the rate of Au electrodeposition and its structure (Amman and Mandler, 2001). 

Electrodeposition of metal onto structured objects, such as circuits, is controlled in part by a template. At the same time, the deposit must fill all the recesses uniformly and seamlessly, the texture and crystal structure must fall within tolerances, and the quality of the features must be sustained over a large workpiece. The distribution of material within recesses or onto widely separated portions of the workpiece is subject to a limited number of macroscopic control-parameters such as applied potential and plating bath composition. Success therefore depends on exploitation of the natural pathways of the process. The spontaneous and unconstrained development of structure must be taken into consideration in the production of highly organized and functional patterns. 

Bulk Ag-Al alloys, containing up to 12 a/o Al, were electrodeposited from melt containing benzene as a co-solvent. Examination by x-ray diffraction (XRD) indicated that the low-Al deposits were single-phase fee Ag solid solutions whereas those approaching 12 a/o were two-phase, fee Ag and hep i>-Ag2Al. The composition at which ti-Ag2Al first nucleates was not determined. The maximum solubility of aluminum in fee silver is about 20.4 a/o at 450 °C [20] and is reduced to about 7 a/o at room temperature. One would expect the lattice parameter of the fee phase to decrease only slightly when aluminum alloys substitutionally with silver because the... 

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