Powder profile studies in electrodeposited cuprous oxide films

Thin films of copper oxide have been electrodeposited cathodically on copper substrates at room temperature. The deposited films have been characterized by X-ray diffraction and scanning electron microscopy. XRD showed the formation of crystalline cuprous oxide (Cu₂O). The XRD peaks are found to be shifted towards lower angle with narrowing of the profiles and the lattice parameter increases with annealing temperature. Scanning electron micrographs showed the formation of localized grain growth region which may be due to the non-uniform deposition of the films. The X-ray diffraction line broadening analysis of the as deposited as well as annealed films have been studied in order to evaluate the microstructural parameters which characterize the microstructural changes. The microstructural parameters like coherent domain size, RMS microstrain and dislocation density have been calculated using Warren-Averbach (Fourier) for multiple order, integral breadth (single and multiple line) and Williamson–Hall plot. The results of analysis obtained by different methods have been compared. The coherent domain size and RMS strain are not found to change appreciably with the increase of film thickness (4–13 μm). The optimum pH value of the electrolytic solution to deposit the films is found to lie in the range 9.2–9.3 where the strain variation is small compared to other pH values. The values of crystallite size and strains obtained by Warren–Averbach method and integral breadth method are comparable. However, Williamson–Hall plot overestimates the values of these two parameters. It is found that the crystallite size increases and RMS strain decreases with the increase of annealing temperature. The dislocation density is also found to decrease with annealing temperature.     

Characterization and degradation testing of nickel pigmented anodic alumina solar selective absorber films produced by alternate and reverse periodic plating technique

Nickel pigmented anodic alumina solar selective absorber films have been prepared using alternate and reverse periodic plating technique. The films show favorable characteristics, high absorptance (α?=?0.97), low emissivity (??=?0.16), for the use as solar selective absorber materials. The effect of the alternate and reverse periodic plating parameters on the optical and films microstructural properties has been studied. Optical and structural properties of the films are investigated using X-ray diffraction, TEM, SEM, EDS, UV/VIS/near IR. These investigations reveal that the nickel particles in alumina pores are spherical with average crystals size ranged from approximately 150–300?Å. The optical characteristics of the films with the preparation conditions are compared. The stability of the films to high temperatures and humidity has been tested. The results from these tests show that the reverse periodic plated films are more sensitive to degradation process mainly nickel oxidation.     

Electrical conductivity of CaZr0.9Y0.1O3−δ films deposited from liquid solutions

CaZr_0.9Y_0.1O_3−δ (CZY) films were fabricated by chemical solution deposition (CSD) from ethanol-based liquid solutions. The films were deposited on single crystals of yttria-stabilized zirconia (YSZ) in (100), (110) and (111) crystallographic orientations. The structural, mechanical and electrical properties of the films have been studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and nanoindentation and impedance spectroscopy methods. XRD and SEM results have shown that the films were polycrystalline. Effect of the substrate orientation on the microstructural, mechanical and electrical properties of CZY films has been examined. The films deposited on (110)-substrates consist of the largest grains; show the highest values of hardness and electrical conductivity. Conductivity of CZY film on (110)-substrates increases with rise in humidity which proves proton transport in the films.     

Hydrogen storage of nanocrystalline Mg–Ni alloy processed by equal-channel angular pressing and cold rolling

Ball-milled nanocrystalline Mg₂Ni powders were subjected to intense plastic straining by cold rolling or equal-channel angular pressing. Morphological and microstructural evolution during these processes has been investigated by scanning electron-microscopy and X-ray diffraction line profile analysis, respectively. Complementary hydrogen absorption experiments in a Sieverts' type apparatus revealed that there exists some correlation between the micro- and nanostructure and hydrogen storage properties of the severely deformed materials.     

Characterization of tin doped indium oxide films prepared by electron beam evaporation

Tin doped indium oxide (ITO) films have been prepared by electron beam evaporation of hot pressed powder of 90% In₂O₃10% SnO₂ by weight. The parameters varied for optimization of film properties have been the substrate temperature and the partial pressure of the oxygen added. Properties which have been studied for characterization are the resistivity, Hall effect, transmittance and optical band gap. The structural studies have been made by X-ray diffraction and transmission electron microscopy. D.c. resistivity in the range 10⁻³−10⁻⁴ Ω cm and visible transmittance in excess of 90% have been obtained for the films, with proper parametric adjustments. A 〈111〉 texture has been generally exhibited by the ITO films, using X-ray diffraction. This has been corroborated by electron diffraction studies.     

Preparation and characterization of chemically deposited CuInS2 thin films

The structural and electrical properties of thin films of CuInS₂ prepared by the chemical deposition technique are described. The composition of the polycrystalline films produced deviate from the ideal composition as shown by energy dispersive X-ray spectrometer (EDS) analysis. Transmission electron diffraction (TED) and X-ray powder analyses showed that the films were single phase with chalcopyrite structure. The films were p-type and the resistivities were in the range of 0.1 to 10 μ cm. Influence of deposition parameters on the surface morphology was observed by SEM.     

Characterization of CdTe thin film—dependence of structural and optical properties on temperature and thickness

The X-ray diffraction analysis of vacuum-evaporated cadmium telluride (CdTe) films reveals that the structure of the films is polycrystalline in nature for the samples prepared at higher substrate temperatures. The crystallite size (D), dislocation density (δ) and strain () were calculated. The composition analysis was made by the energy dispersive X-ray analysis. It confirmed the equal distribution of Cd and Te elements in the CdTe films. The fundamental optical parameters like band gap and extinction coefficient are calculated from the transmission spectra. The possible optical transition in these films is found to be direct and allowed. The charge transport phenomenon appears to be space charge limited conduction. Various electrical parameters were determined from the I–V analysis.     

Analytical characterization of cadmium cyanamide in CdS thin films and bulk precipitates produced from CBD process in pilot plant

CdS thin films and bulk precipitates were obtained by chemical bath deposition (CBD) in a well-closed reactor. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, thermal analysis, elemental analysis and leaching have been used to characterize solids and thin films. It has been shown that the proportion of cadmium cyanamide in solids may vary from about 50% to 2% according to physicochemical conditions in solution (time after CBD, ammonia concentration) and that CdO results from CdCN₂ after air annealing of thin films. This last step also increases the crystallinity of the films.     

Structural, compositional, and optical properties of electrochemically deposited stoichiometric CdSe thin films from non-aqueous bath

In the recent years, cadmium chalcogenide compounds have been extensively investigated because of their potential applications in solar energy conversion. Thin films of CdSe have been deposited onto the stainless steel and fluorine doped tin oxide (FTO) coated glass substrates using simple and inexpensive electrodeposition technique. The non-aqueous solvent ethylene glycol (CH₂OHCH₂OH) containing precursors of Cd and Se with ethylenediaminetetraacetic acid (EDTA) tetra sodium salt as a complexing agent is used to obtain stoichiometric deposits. Deposition potential was estimated from polarization curves and other preparative parameters such as bath temperature and concentration of solution were optimized. X-ray diffraction (XRD) analysis reveals that the films are polycrystalline with cubic structure. PEC study shows the CdSe films are photoactive. Optical absorption study shows the presence of direct transition with band gap energy 1.72 eV. The energy dispersive analysis by X-rays (EDAX) reveals that the substrate is well covered with large number of grains indicating compact structure. The average ratio of the atomic percentage of Cd:Se is 50.31:49.69, showing that the deposited films are almost stoichiometric.     

Formation of CuInSe2 and Cu(In,Ga)Se2 films by electrodeposition and vacuum annealing treatment

Polycrystalline thin films of CuInSe₂ and Cu(In,Ga)Se₂ (CIGS) were grown on both polished Mo substrates and Mo-coated glass substrates by one-step electrodeposition. All the as-deposited films have been annealed in vacuum at 450°C for a short time to improve the crystalline properties. The films have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The results indicate that the crystallization of the films was greatly improved after annealing. Further more, a CIGS film with 23 at% Ga was obtained.     

Growth and characterization of ZnO thin films prepared by electrodeposition technique

ZnO thin films were deposited on either indium tin oxide-coated glass or copper substrate by the electrodeposition process, using zinc chloride and flowing air as precursors. The effect of pH on the structural and morphological ZnO films was studied and the optimum deposition conditions have been outlined. The kinetics of the growth of the films have been investigated. We note that the rate of deposition of ZnO in an acidic solution was larger than in a basic solution. The structure of the films was studied using X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The surface morphology and thickness of the films were determined using scanning electron microscopy. The X-ray diffraction analysis shows that the films are polycrystalline with hexagonal crystal structure (zincite) at pH 4. The optical transmittance of ZnO decreases with varying film thickness. The optical energy bandgap was found to be 3.26 eV.     

Photoactive iron pyrite films for photoelectrochemical (PEC) cells

Photoactive iron pyrite (FeS₂) films have been grown by sulfurization of sprayed iron oxide films. The structural properties were studied using X-ray diffraction. The films showed good crystallinity with grain size ≈500 Å. These films have been used as photoanode in photoelectrochemical cells.     

Production and Characteristics of (ZnSe)<Subscript>0.1</Subscript>(SnSe)<Subscript>0.9</Subscript> Films for Use in Thin Film Solar Cells

(ZnSe)_x(SnSe)_1–x films have been produced using chemical molecular beam deposition (CMBD) from an ZnSe and SnSe compound with a stoichiometric composition at a substrate temperature of 500°С. The structural, morphological, and electrophysical properties of (ZnSe)_0.1 (SnSe)_0.9 films are studied. The size of film grains is 5–6 μm. The results of X-ray diffraction analysis of specimens have revealed that the films have a crystalline (orthorhombic) structure. The structural parameters of the produced films are presented. The electrical conductivity of the films measured using the Van der Pauw method varies within 15–0.6 Ω cm^–1.     

Optical and photoelectrical properties of Bi2S3 thin films obtained by spray pyrolysis technique

Polycrystalline films of Bi₂S₃ compound have been prepared, at substrate temperature of 570 K, from Bismuth chloride (BiCl₃) and Thiourea (CS (NH₂)₂) solutions. The structural characterisation has been carried out by the X-ray diffraction analysis (XRD). Study of optical properties shows that Bi₂S₃ compound has an allowed indirect transition at 1.43 eV energy. The photoelectrical parameters (diffusion length and lifetime) have been determined from the study of the photoconductivity.     

Structural and electrical properties of magnetron sputtered Ti(ON) thin films: The case of TiN doped in situ with oxygen

Incorporation of oxygen into TiN lattice results in formation of titanium oxynitrides, TiO_xN_y that have become particularly interesting for photocatalytic applications. Elaboration as well as characterization of TiN and in situ oxygen-doped thin films is the subject of this paper. Thin films, 250-320 nm in thickness, have been deposited by dc-pulsed magnetron reactive sputtering from Ti target under controllable gas flows of Ar, N₂ and O₂. Optical monitoring of Ti plasma emission line at λ = 500 nm has been implemented in order to stabilize the sputtering rate. Scanning electron microscopy (SEM), X-ray diffraction in grazing incidence (GIXRD), micro-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), optical spectrophotometry and four-point probe electrical resistivity measurements have been performed in order to follow evolution of film physical parameters as a function of the oxygen flow rate ηO₂ at which the films were deposited. The relationship between ηO₂ expressed in standard cubic centimetres per minute, sccm and the nitrogen/oxygen content in thin films has been established by means of the analysis of the XPS spectra. GIXRD studies indicate that incorporation of oxygen results in a progressive loss of preferential orientation in 〈1 1 1〉 direction, a change in the grain size from 16 nm for TiN to about 3 nm for films deposited at ηO₂=1.32 sccm and a decrease in the lattice constant. A systematic shift of all X-ray diffraction (XRD) lines towards higher diffraction angles is consistent with substitution of oxygen for nitrogen. Micro-Raman investigations indicate amorphisation of thin films upon oxidation. Binding energies determined from fitting of the XPS results concerning the N1s and Ti2p lines give evidence of the presence of TiO_xN_y compound. Red-shift of the plasma reflectance edge upon TiN oxidation is correlated with a decreased carrier concentration. Metal-semiconductor transition can be expected on the basis of the electrical conductivity decrease and development of the fundamental absorption across the forbidden band of TiO₂ upon increase in the oxygen flow rate. Additional absorption feature in the visible range, being a consequence of coexistence of free-electron and interband absorption within almost the same spectral range (λ = 400-600 nm) seems to be very promising for photocatalytic applications of titanium oxynitride thin films.     

Preparation and characterization of copper indium diselenide films by electroless deposition

The preparation of copper indium diselenide (CIS) films by electroless deposition technique is reported. The films have been deposited on molybdenum substrates. The deposition bath consisted of aqueous solutions of copper chloride, indium chloride, selenous acid and lithium chloride. The pH of the bath was adjusted to 2.2 by adding dilute HCl. The Mo substrate was short-circuited with the aluminum counter electrode for the electroless deposition. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), inductively coupled plasma spectroscopy (ICP), Auger electron spectroscopy (AES) and optical spectroscopy. The results indicate that reasonable quality CIS films can be grown by simple electroless deposition process followed by recrystallization in selenium atmosphere.     

Influence of CdCl2 treatment on structural and optical properties of vacuum evaporated CdTe thin films

In this article we have discussed the structural, optical properties of vacuum evaporated CdTe thin films before and after CdCl₂ treatment. The CdTe thin films were prepared by vacuum evaporation. Films were prepared under the vacuum of 10⁻⁶ Torr. The structural studies have been performed by the X-ray diffraction (XRD) technique. The XRD analysis of vacuum evaporated CdTe films reveals that the structure of films is polycrystalline in nature. However, the crystallinity has been improved after the CdCl₂ treatment as shown by an increase of the diffraction peak intensities. This is due to the enhancement in the atomic mobility of CdTe. The optical properties of the CdTe thin films have been studied by the spectrophotometer in the 300–800 nm wavelength range. It is observed that the optical band gap energy is highly dependent on CdCl₂ treatments. The optical transitions in these films are found to be direct and allowed.     

Preparation and properties of a Cu---In alloy precursor for CuInSe2 films

We describe a new nonaqueous method to electrodeposit Cu---In alloy precursor for n-CuInSe₂ films. The structural and compositional analysis of the Cu---In alloy carried out by X-ray diffraction and X-ray photoelectron spectroscopy have also been discussed. The stoichiometry of the films has been found to be influenced by the deposition potential. It is shown that a Cu---In alloy precursor with bulk Cu/In ratio of 1.00 can be electrodeposited at a potential of −1.05 V (versus Pt). Flash annealing of the stacked Cu---In alloy/Se layers has been used to prepare CuInSe₂ films. It is shown that the flashed n-CuInSe₂ films have a chalcopyrite structure with strongly oriented (112) U planes.     

Effect of substrate temperature on the structure and optical properties of CdTe thin film

The present work deals with the preparation, structure and optical characterization of cadmium telluride (CdTe) thin films. These films are formed by vacuum evaporation on the well-cleaned glass substrates. The compositional analyses are made by energy dispersive analysis by X-ray. The thicknesses of the samples are measured by multiple beam interferometry. The samples are prepared at different substrate temperatures. The X-ray diffraction has been employed to study the structure of the film. The structures of the samples are found to be crystalline and the crystallite size increases with the increase of substrate temperature. The d-spacing and lattice parameters of the samples are calculated and the results are also discussed. Optical characteristics of the CdTe samples have been analyzed using spectrophotometer in the wavelength range of 400–800 nm. The transmittance is found to decrease with the increase of film thickness. The transmittance falls steeply with decreasing wavelength. It reveals that CdTe films are having considerable absorption throughout the wavelength region (400–800 nm). The optical band gap energy has been evaluated from the plot of α² vs. hν. Two possible direct transitions have been observed for all the CdTe films in visible region. The observed allowed transition may be attributed due to the spin orbit splitting of the valence band.     

Preparation and study of structural and optical properties of CSVT deposited CuInSe2 thin films

A simple close-spaced vapour transport (CSVT) system has been designed and fabricated. Copper indium diselenide (CuInSe₂) thin films of wide range of thickness (4000–60000 Å) have been prepared using the fabricated CSVT system at source temperatures 713, 758 and 843 K. A detailed study on the deposition temperature has been made and the temperature profile along with the reaction kinetics is reported. The composition of the chemical constituents of the films has been determined by energy dispersive X-ray analysis. The structural characterization of the as-deposited CuInSe₂ films of various thicknesses has been carried out by X-ray diffraction method. The diffractogram revealed that the CuInSe₂ films are polycrystalline in nature with chalcopyrite structure. The structural parameters such as lattice constants, axial ratio, tetragonal distortion, crystallite size, dislocation density and strain have been evaluated and the results are discussed. The surface morphology of the as-deposited CuInSe₂ thin films has been studied using scanning electron microscope. The transmittance characteristics of the CuInSe₂ films have been studied using double beam spectrophotometer in the wavelength range 4000–15000 Å and the optical constants n and k are evaluated. The absorption coefficient has been found to be very high and is of the order of 10⁵–10⁶ m⁻¹. CuInSe₂ films are found to have a direct allowed transition and the optical band gap is found to be in the range 0.85–1.05 eV.