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CdS nanocrystalline thin films were synthesized by chemical bath deposition for different deposition times (10–75 min) and the semiconducting and photo-electrochemical properties were investigated. The results indicate that the deposition rate decreases with the deposition time, due to the depletion of Cd2+ and S2− ions near the glass subtract. The structure is characterized by X-ray diffraction; the films crystallize in a cubic blende structure with (111) as a preferential orientation and the crystallite size varies between 13 and 35 nm. The surface morphology, studied by atomic force microscopy, indicates that the growth process occurs through ion by ion mechanism because of the stability of the complex Cd(NH3)4 (~7), the small deposition rate corroborates this result. The UV visible spectra of the films indicate a high transparency (80%). The transmittance data analysis give a variable forbidden band (2.2–2.4 eV), closely related to the deposition time and agree with the disorder range (230–500 meV). The capacitance–voltage measurement exhibits a linear behavior, characteristic of n type conduction, from which a flat band potential of −0.92 VSCE is determined. The Nyquist plot shows a semicircle assigned to the bulk contribution (=2.5 Ω cm2); the center is located below the real axis (−10°), ascribed to a constant phase element (CPE). A fill factor (FF) of 0.37 and energy conversion of 0.38% are obtained under visible illumination. As application, eosin solution (15 ppm) i oxidized under visible light; the best activity is obtained at pH ~6.3. 80% of eosin disappears after 1 h of exposition and the kinetic obeys to a first order model with a rate constant of 4.5 × 10−2 min−1.

Zn-doped CdS layers, with various percentage ratios [Formula: see text] (= [Zn[Formula: see text]]/[Cd[Formula: see text]]%) were grown on glass substrates by chemical bath deposition (CBD). The effect of Zn-doping on different properties of CdS is studied by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, atomic force microscopy, energy dispersive X-ray analysis and UV-visible diffuse reflectance. The XRD patterns indicated polycrystalline films with (111) orientation and the insertion of Zn does not change the crystallinity of CdS. The Raman spectra show one major peak centered around 300[Formula: see text]cm[Formula: see text] assigned to the first-order longitudinal optic (LO) phonon modes of CdS. The surface morphology visualized by AFM and SEM analysis showed the influence of the Zn-doping on the morphology of the films, the surface roughness is found to decrease from 16.5 to 8.9[Formula: see text]nm with augmenting the ratio [Formula: see text] from 0 to 6%. In regard to the SEM analysis, the increase of [Formula: see text] yielded a lower porosity of the film and voids, and the films become more homogeneous. The EDAX spectra confirmed the existence of Zn in the doped samples. The bandgap decreases from 2.44 to 2.37[Formula: see text]eV, while the transmittance increases from 76 to 86% with augmenting the ratio [Formula: see text].

The influence of the thickness on the optical, structural and morphological properties of CdS thin films elaborated by chemical bath deposition is studied. The deposition time varies between 15 and 75 min and the optical measurements show that the films have high optical transmission (85%). The band gap presents a maximum of 2.44 eV for a deposition time of 30 min which corresponds to a lower disorder. The deposition rate ( n type conductivity with a flat band potential of −0.95 V SCE and an electron density of 1.43×10 25 m −3 . The Nyquist plot shows the predominant contribution of the grain boundaries; the data are modeled to an equivalent circuit with a constant phase element. As application, orange II is oxidized via radicals and the best photoactivity is obtained at pH~7. 68% of orange II disappears in ~1 h under solar light (AM 1). The oxidation follows a zero order kinetic with a rate constant of 0.11 mol L −1 min −1 .

A study of electrical transport in CdS thin films is reported. We have observed, for the first time, that CdS thin film conductivity obeys the Meyer–Neldel rule (MNR). This was deduced from linking the conductivity pre-exponential factor to the activation energy variation. CdS films were deposited by chemical bath deposition at different solution temperatures in order to vary the electrical activation energy of the films. A correlation between the MNR rule and the disorder in the film network is highlighted. The multi-trapping process in the band tail-localized states governs the conductivity in CdS films. This explains the MNR observation in CdS films. The variation of the electrical conductivity pre-exponential factor and activation energy are correlated to the disorder in the film network; this was explained in terms of polaron formation and phonon–electron coupling with disorder.

Cubic cadmium sulphide (CdS) thin films with (111) preferential orientation were prepared by chemical bath deposition (CBD) technique, using the reaction between NH 4 OH, CdSO 4 and CS(NH 2 ) 2 . The films properties have been investigated as a function of bath temperature and deposition time. Structural properties of the obtained films were studied by X-ray diffraction analysis. The structural parameters such as crystallite size have been evaluated. The transmission spectra, recorded in the UV visible range reveal a relatively high transmission coefficient (70%) in the obtained films. The transmittance data analysis indicates that the optical band gap is closely related to the deposition conditions, a direct band gap ranging from 2.0 eV to 2.34 eV was deduced. The electrical characterization shows that CdS films' dark conductivities can be controlled either by the deposition time or the bath temperature.

The present work deals with the preparation and characterization of cadmium sulfur (CdS) thin films. These films are prepared by chemical bath deposition on the well cleaned glass substrates. The thickness of the samples was measured by using profilometer DEKTAK, structural and optical properties were studied by X-ray diffraction analysis, and UV-visible spectrophotometry. The optical properties of the films have been investigated as a function of temperature. The band gap energy and Urbach energy were also investigated as a function of temperature. From the transmittance data analysis the direct band gap ranges from 2.21 eV to 2.34 eV. A dependence of band gap on temperature has been observed and the possible raisons are discussed. Transmission spectra indicates a high transmission coefficient (75 %). Structural analysis revealed that the films showed cubic structure, and the crystallite size decreased at a higher deposition temperature.

In this work we report the structural, optical and electrical properties of CdS thin films prepared by chemical bath deposition (CBD) under the effect of solution temperatures. The solution temperatures used vary between 55 and 75 °C. The XRD patterns show that the films have a hexagonal phase with a preferential (002) orientation. The structural parameters such as the grain size, dislocation density and strain are calculated. The transmission spectra, recorded in the UV visible range, reveal a high transmission coefficient (85%) of the prepared films and an optical band gap values of 2 – 2.4 eV. The electrical measurements show that the dark conductivity values increase from 10−7 to 10−4 (Ω.cm)−1 at higher temperature (Ts > 65°C). It is found that the photoconductivity of the deposited films is two to five decades larger than the dark conductivity, and the photoconductivity to the dark conductivity ratio obtained at 3000 Lx vary from 102 to 105. From these results we inferred that the elaborated CdS thin films exhibit good properties intended for solar cell window layers.

This work deals with the preparation of cadmium sulfide (CdS) thin films by chemical bath deposition. The influence of the solution temperature is investigated in this study. We suggest that activation energy of the deposition rate measurement can be a tool for determining the nature of the deposition mechanism. We found that at low solution temperature, the growth mechanism proceeds via the ion by ion process, and found the corresponding activation energy equal to 0.06 eV. However, at higher solution temperature, the film deposition became via the cluster by cluster process, the growth rate activation energy is equal to 0.48 eV. The films' structural and optical properties were studied by x-ray diffraction analysis and UV–visible spectrophotometry. Structural analysis revealed that the deposited films have a cubic structure, and the crystallite size decreases with increasing deposition temperature. The transmission spectra of the film, in the visible range, show a high transmission coefficient (70%). The transmittance data analysis indicates that the optical band gap is closely related to the solution temperature. From this analysis, a direct band gap ranging from 2.21 to 2.34 eV was deduced. From the electrical characterization we inferred that CdS films are n-type and their dark conductivities reduced with increasing bath solution temperature. From the photoconductivity measurements we concluded that films deposited at low temperatures (less than 60 °C) or high temperatures (higher than 70 °C) have good optoelectronic properties suitable for utilization as a buffer layer in thin film solar cells.