Electrodeposition Of Thin Films Research Articles

An analysis of the temperature-induced supersaturation effects on structure and properties of sono-electrodeposited copper thin films

The mechanism of electrodeposition of copper thin film on aluminum has been studied under the influence of power ultrasound using cyclic voltammetry. The deposited thin films were characterized by X-ray diffraction, scanning electron microscopy and atomic force microscopy. Films are crystalline in structure. The spherical copper domains of the deposits without sonication have been converted to mushroom structures in the presence of ultrasound. Properties, including thermal and mechanical are further analyzed using differential scanning calorimeter and nano-indentation. There is a significant change in the variation of thermal stability for films that were deposited at different bath temperatures. The observed hardness values are closely conforming to the reported data available in the open literature. Further the soft films are found to have good wear properties.

Films of Highly Disperse Electrodeposited Poly(N‐vinylcarbazole)–Graphene Oxide Nanocomposites

AbstractThe electrodeposition of polymer nanocomposite thin films of PVK–GO is demonstrated. Highly exfoliated and stable graphene oxide (GO) solutions are prepared by incorporating poly(N‐vinylcarbazole) (PVK) through mixing. Enhanced stability up to 30 d is observed in both aqueous and organic solvents. TGA, XRD, FTIR, and UV‐vis measurements confirm nanocomposite formation. CV enables electrodeposition of the films. The presence of GO on the PVK–GO surface is confirmed by the appearance of the C=O and OH stretching vibrations, attributed to the carboxylic and hydroxyl groups of GO. AFM measurements show homogeneous and well‐defined film morphology.

Electrodeposition of thin films and nanowires Ni–Fe alloys, study of their magnetic susceptibility

Electrodeposition of thin films and nanowires Ni–Fe alloys is presented. For the thin films, we have studied the impact of various electrolytic conditions (magnetic induction, pH, and substrate) on the composition and magnetic susceptibility. Whatever the electrolytic conditions, the evolution of the composition versus the polarization exhibited first a decrease of the Ni content within the deposit followed by an increase. However, at constant polarization, the obtained values were different. Concerning the evolution of the magnetic susceptibility versus the composition, it is known that it decreases with the enhancement of the Ni percentage. The reason is that the susceptibility of iron is higher than that of Ni. It can also observe a sharp rupture in the evolution of magnetic susceptibility, which appeared near the Invar composition (Ni36Fe64). Our results show that the electrolytic conditions do not affect the position of the rupture point for the thin films but modify the susceptibility values. For the nanowires, a polycarbonate membrane has been used as a template. The structural characteristics of wires were examined using X-ray diffraction. According to the composition and as described in the literature for the electrodeposited thin films, a change between the body-centered cubic structure and face-centered cubic structure was obtained for the nanowires. However, for the nanowires this modification appeared for a lower Ni content than for this in thin films. Finally, a comparison of their magnetic susceptibility with thin films exhibited a shift toward the lower Ni contents for the rupture point.

Electrochemical preparation of thin rhenium-tellurium coatings from chloride-borate electrolyte

The kinetics and mechanism of cathode electrodeposition of thin Re-Te films from a chloride-borate electrolyte containing NH4ReO4, TeO2, HCl, and H3BO3 were studied. The region of potentials in which rhenium is electrodeposited together with tellurium was determined by cyclic voltammetry. The combined electrodeposition of rhenium and tellurium occurred with minor depolarization due to the energy liberated during the formation of the Re-Te alloy.

Effect of pH and Temperature on the Electrodeposition of Co-Mn Oxide Thin Films

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Electrodeposition of CoNiMo thin films using glycine as additive: anomalous and induced codeposition

The present study focuses on the behavior of the CoNiMo mixed anomalous/induced codeposition process, using glycine as a probe to influence the coverage of adsorbed intermediates. In order to facilitate the investigation of a wide variation of parameters the electrodeposition of the alloy films was performed using a rotating cylinder Hull cell. Alloy composition, current efficiency and partial currents of each metal were analyzed. The partial current densities and hence alloy composition was affected by the amount of glycine in the electrolyte: increasing glycine enhanced both cobalt and molybdenum deposition rates and hindered nickel deposition. It is suggested that the glycine facilitates the adsorption of M(I) adsorbed intermediates that control the anomalous and induced codeposition behavior. The current efficiency ranged from 30 up to 75% and was only slightly affected by glycine at high applied current densities. Films with a tridimensional porous structure were obtained applying current densities higher than 200 mA cm −2, formed as a consequence of the large hydrogen evolution side reaction, presenting conditions for a novel Mo-alloy electrode structure.

Formic Acid Oxidation on Pt100−xPbx Thin Films Electrodeposited on Au

Electrocatalytic formic acid oxidation is examined on electrodeposited Pt100−xPbx thin films grown on textured Au(111). Metastable fcc Pt100-xPbx (0 < x atom % < 50) films exhibit significantly enhanced catalysis for formic acid oxidation relative to Pt films of similar roughness. At − 0.15 V SCE an enhancement factor in excess of 100 is evident between Pt83Pb17 and Pt films of similar roughness. Electrodeposition of near stoichiometric PtPb thin films yields a smooth compact surface that exhibits enhanced electrocatalytic activity relative to a Pt electrode. X-ray diffraction reveals a P63/mmc intermetallic phase while TEM indicates the formation of fcc Pt100-xPbx lattice with dimensions almost lattice matched to Au(111) and/or Pt3Pb. After considering the surface roughness, the electrocatalytic activity of the compact PtPb and rough metastable fcc phase are similar in magnitude. Durability was examined by chronoamperometry and cyclic voltammetry. The Pb-rich and PtPb films are substantially dealloyed particularly at higher potentials. The dealloyed structure still exhibits significant electrocatalytic behavior that is presumably related to Pb upd on available Pt surface sites.

Controlled Potential Electrodeposition and Characterization of ZnTe Thin Films on Indium Tin Oxides

Electrodeposition of ZnTe thin films by controlled potential method from aqueous solutions on ITO were done to investigate characteristics suitable as a window material in solar cells technology. The influence deposition of potential towards the Zn:Te ratio and the crystallinity are discussed. The electrodeposited films were investigated by using X-Ray Diffraction and Energy Dispersive Analysis of X-Ray. The Te content decreases at higher deposition potentials.

Electrodeposition of antimony telluride thin films from acidic nitrate-tartrate baths

Electrochemical quartz crystal microbalance (EQCM) and rotating disk electrode (RDE) techniques were utilized to systematically investigate the electrodeposition of Sb x Te 1− x (0.1 < x < 0.8). In addition, the effect of applied potential and agitation were correlated to the film composition, crystal structure, and morphology. Although the film composition was independent of the agitation rate, the deposition rate, current efficiency, crystallinity and phase of Sb x Te 1− x were all strongly influenced by it. The deposition rate monotonically increased with increases in the rotation rate because of the faster diffusion rate of HTeO 2 + ions to the cathode. Amorphous thin films were electrodeposited in the absence of agitation, whereas polycrystalline Sb 2Te 3 with elemental Sb and Te were co-deposited at a higher agitation independent of the applied deposition potential.

(Research Award of the Energy and Technology Division) (Photo)Electrochemistry in the Service of Solar Energy Conversion

The paper is a short summary of the lecture delivered for the 2011 Research Award of the Energy Technology Division. The main expertise field of my group is materials science and (photo)electrochemistry for energy conversion and storage. The motivations that oriented my research are described, spanning from photoelectrochemistry of single crystal semiconductors, p-n photoelectroelectrochemical cells for solar hydrogen generation, to the photoetching of semiconductors, electrochemical processing of silicon surface including porous silicon, electrodeposition of polycrystalline semiconductor thin films and monocrystalline nanowires and development of Eta (extremely thin absorber) solar cells.

Electrodeposition of nanocrystalline CdSe thin films from dimethyl sulfoxide solution: Nucleation and growth mechanism, structural and optical studies

Cadmium selenide (CdSe) nanocrystalline semiconductor thin films have been synthesized by electrodeposition at controlled potential based in the electrochemical reduction process of molecular selenium in dimethyl sulfoxide (DMSO) solution. The nucleation and growth mechanism of this process has been studied. The XRD pattern shows a characteristic polycrystalline hexagonal wurtzite structure with a slight (1 0 1 0) crystallographic preferred orientation. The crystallite size of nanocrystalline CdSe thin films can be simply controlled by the electrodeposition potential. A quantum size effect is deduced from the correlation between the band gap energy and the crystallite size.

In situ grazing-incidence X-ray diffraction during electrodeposition of birnessite thin films: Identification of solid precursors

A special electrochemical flow-cell allowing in situ grazing-incidence X-ray diffraction during electrodeposition of thin films has been successfully developed. This original setup is very simple and permits characterisations by reflection onto large surfaces by using an X-ray transparent window used also as a counter electrode. This cell was tested by studying the electrodeposition of birnessite thin films as a function of background electrolytes. In Na 2SO 4 solution, buserite was identified as the only in situ solid precursor. Its dehydration into birnessite was monitoring in real time and was complete in few minutes. In K 2SO 4 aerated solution, birnessite was electrodeposited directly as very small crystals. This demonstrates the usefulness of this electrochemical flow-cell for characterising compounds during electrochemical measurements.

Potentiostatic electrodeposition of cuprous oxide thin films for photovoltaic applications

Potentiostatic deposition of Cu 2O thin films on glass substrates coated with F-doped SnO 2 from an alkaline electrolyte solution (pH 12.5) containing copper (II) sulfate and lactic acid was studied for fabrication of a Cu 2O/Al-doped ZnO (AZO) heterojunction solar cell. The band gap of the electrodeposited Cu 2O films was determined by photoelectrochemical measurements to be around 1.9 eV irrespective of the applied potentials. The solar cells with a glass/FTO/Cu 2O/AZO structure were fabricated by sputtering an AZO film onto the Cu 2O film followed by deposition of an Al contact by vacuum evaporation. The highest efficiency of 0.603% was obtained with a Cu 2O film deposited at −0.6 V (vs. Ag/AgCl). This was attributed to better compactness and purity of the Cu 2O film than those of the Cu 2O films deposited at other potentials.

Electrochemical reduction of O2 in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid containing Zn2+ cations: deposition of non-polar oriented ZnO nanocrystalline films

The influence of the Zn(2+) concentration and temperature on the electrochemical reduction of O(2) in a solution of zinc bis(trifluoromethanesulfonyl)imide (Zn(TFSI)(2)) salt in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR(14)TFSI) ionic liquid is presented. ZnO nanocrystalline films were then electrodeposited, under enhanced O(2) reduction, at temperatures in the 75-150 °C range. Their morphology, chemical composition, structural and optical properties were analyzed. In contrast to the polar-oriented ZnO usually obtained from aqueous and conventional solvent based electrolytes, nanocrystalline films oriented along non-polar directions, (11 ̅10) and (11 ̅20), were obtained from this ionic liquid electrolyte. A significant content of carbon was detected in the films, pointing to the active participation and crucial effect of pyrrolidinium cation (and/or byproducts) during the electrodeposition. The films showed semiconducting behavior with an optical gap between 3.43 and 3.53 eV as measured by optical transmittance. Their room temperature photoluminescence spectra exhibited two different bands centered at ∼3.4 and ∼2.2 eV. The intensity ratio between both bands was found to depend on the deposition temperature. This work demonstrates the great potential of ionic liquids based electrolytes for the electrodeposition of ZnO nanocrystalline thin films with innovative microstructural and optoelectronic properties.

Electrical and optical characteristics of Au/PbS/n-6H–SiC structures prepared by electrodeposition of PbS thin film on n-type 6H–SiC substrate

To realize Schottky barrier height (SBH) modification in the Au/n-6H–SiC Schottky diodes, lead sulfide (PbS) thin films were grown on n-6H–SiC by electrodeposition method. At first, XRD experiments were performed to investigate the crystal structure of the PbS film electrodeposited on n-6H–SiC. It has been deduced from the diffraction profile that the PbS thin film has a crystal structure more strongly oriented along the [2 0 0] direction. An optical energy band gap value of 1.42 eV for the PbS film was obtained from its optical absorption spectra. Then, we have prepared Au/PbS/n-6H–SiC Schottky barrier diodes (SBDs) with interface layer and reference Au/n-6H–SiC/Ni SBDs. The SBH enhancement has been succeeded by the PbS interlayer, influencing the space charge region of the SiC. The SBH values of 1.03 and 0.97 eV for the samples with and without the interfacial PbS layer were obtained from the forward bias current–voltage ( I– V) characteristics. The SBH increase in the Au/PbS/n-6H–SiC SBD with the interfacial PbS layer has been attributed to the fact that the interface states contain a net negative interface charge in metal/n-type semiconductor contact due to the presence of the interfacial PbS layer.

Effects of Potassium on the Supramolecular Structure and Electronic Properties of Eumelanin Thin Films

The role of potassium in the formation of synthetic eumelanin aggregates is investigated by atomic force microscopy and soft-X-ray spectroscopy. Control over the thin film granularity is achieved by using K salts, in both drop casting and electrodeposition of eumelanin thin films. Further control over orientation is made possible by a suitable choice of the substrate: evidence of self-assembly is found for thin films deposited on gold. Finally, it is shown that the potassium content affects not only the samples morphology, but also the low-lying states in the valence band, where a transfer of spectral weight across the HOMO-LUMO gap is observed, disclosing possible applications of this multifunctional biomacromolecule.

Electrodeposition and growth mechanism of SnSe thin films

Tin selenide (SnSe) thin films were electrochemically deposited onto Au(111) substrates from an aqueous solution containing SnCl2, Na2SeO3, and EDTA at room temperature (25°C). The electrochemical behaviors and the codeposition potentials of Sn and Se were explored by cyclic voltammetry. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and UV–vis absorption spectroscopy were employed to characterize the thin films. When the electrodeposition potential increased, the Se content in the films decreased. It was found that the stoichiometric SnSe thin films could be obtained at −0.50V. The as-deposited films were crystallized in the preferential orientation along the (111) plane. The morphologies of SnSe films could be changed from spherical grains to platelet-like particles as the deposition potential increases. The SEM investigations show that the film growth proceeds via nucleation, growth of film layer and formation of needle-like particles on the overlayer of the film. The optical absorption study showed the film has direct transition with band gap energy of 1.3eV.

Electrodeposition of low-stress NiFe thin films from a highly acidic electrolyte

Physical properties, such as surface morphology, microstructure, and stress, were investigated for electrodeposited NiFe soft magnetic thin films synthesized from a highly acidic electrolyte. The characteristics of the anomalous NiFe electrodeposition diminished when the temperature of the electrolyte increased. The FCC structure was the dominant microstructure of the NiFe alloys until the Fe content was increased to ~ 40%. The film stress was maximal when the composition was 60Ni40Fe. The coercivity of the NiFe alloy thin film decreased to 10 Oe when the composition was 80Ni20Fe. The stress and coercivity of NiFe thin films were highly related to the variation of the alloy composition, which caused a change in the grain size.

Effect of potential on the early stages of nucleation and growth during cobalt electrocrystallization in sulfate medium onto FTO surface

The electrodeposition of Co thin films onto a fluorine-doped tin oxide (FTO)-coated conducting glass substrate from sulfate solutions was investigated using cyclic voltammetry, and chronoamperometry measurements. The Scharifker and Hills model was used to analyze current transients. At relatively low overpotentials, the Co deposition can be described by a model involving instantaneous nucleation on active sites and diffusion-controlled 3D growth. The values of kinetic parameters, number density of active sites N∞, and diffusion coefficient D for Co2+ ions are also calculated.

ChemInform Abstract: One-Step Electrodeposition of Cu2-xSe and CuInSe2 Thin Films by the Induced Co-deposition Mechanism.

ChemInform Abstract: One-Step Electrodeposition of Cu2-xSe and CuInSe2 Thin Films by the Induced Co-deposition Mechanism.