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In this work, we have prepared the undoped and Al-doped ZnO thin films by a homemade spray pyrolysis method at 450°C onto glass substrates. The X-ray diffraction patterns of undoped ZnO and aluminized zinc-oxide (AZO) thin films exhibit hexagonal wurtzite crystal structure with high crystalline quality, the crystallite size is nanometric. The morphology of the undoped and Al-doped ZnO thin films also indicate that all samples have a nanoscale grain size around 50 nm, and the microstructure of ZnO films is highly influenced by the aluminum doping. The two films are characterized by UV-visible spectrophotometry showing that the films have a whole optical transmission above 85% in the visible range. The composition of our films is obtained by energy dispersive spectrum, confirmed by Auger electron spectroscopy (AES) and by Rutherford back-scattering spectrometry (RBS) techniques. [ABSTRACT FROM AUTHOR]

In this paper, the structural, electronic and magnetic properties of the GdSn3, CmSn3 and GdxCm1-xSn3 compounds (x = 0:25, 0:5 and 0:75) were studied using the full-potential linearized augmented plane wave method, within the generalized gradient approximation+U. The ground-state properties are determined for the bulk materials GdSn3, CmSn3 and GdxCm1-xSn3 crystallized in AuCu3-type structure. The calculated structural, electronic and magnetic properties of GdSn3 compound are in good agreement with the existing experimental and theoretical data. It is found that the most stable magnetic con1gurations of both compounds CmSn3 and GdSn3 are anti-ferromagnetic type A (AFM-A) and have a metallic behavior. The magnetic moment found decreases with increasing the Cm composition in GdxCm1-xSn3 compounds. The results show that the GdSn3, CmSn3 and GdxCm1-xSn3 compounds share some properties, and may well be useful for spintronic applications. [ABSTRACT FROM AUTHOR]

Undoped ZnO thin films have been prepared on glass substrates at different substrate temperatures by spray pyrolysis method. The effect of temperature on the structural, morphological and optical properties of n-type ZnO films was studied. The X-ray diffraction (XRD) results confirmed that the ZnO thin films were polycrystalline with wurtzite structure. Scanning electron microscopy (SEM) measurements showed that the surface morphology of the films changed with temperature. The studies demonstrated that the ZnO film had a transmission of about 85 % and energy gap of 3.28 eV at 450 °C. The RBS measurements revealed that ZnO layers with a thickness up to 200 nm had a good stoichiometry. [ABSTRACT FROM AUTHOR]

Abstract: Fluorine doped SnO2 thin films were spray deposited using three tin precursors, tin tetrachloride, dibutyl-tin-diacetate and butyl-tin-trichloride, adding small amounts of hydrogen peroxide (H2O2) to the source solutions. The molar ratio range [H2O2]/[Sn]=0 to 0.8 with respect to the tin precursor was investigated. At a given deposition temperature T d, a net optimum was found close to [H2O2]/[Sn]=0.5 for the deposition rate, the electrical properties and the crystalline quality. The effect of H2O2 addition was found to increase the growth rate, even at a temperature as low as 340 °C. The higher was the deposition temperature T d, the larger was the increase. The deposition process of FTO films was optimized at T d =420 °C. At this temperature, the most significant result with respect to solar cell applications was obtained with butyl-tin-trichloride as tin precursor and [H2O2]/[Sn]=0.6; carrier concentration : 4.5×1020 cm−3; mobility : 34 cm2 V−1 s−1; resistivity: 4.1×10−4 Ω cm. It is concluded that the main effect of addition of hydrogen peroxide is to improve the film crystallization at a lower T d than in the absence of H2O2, increasing the carrier mobility significantly and keeping a high deposition rate. [Copyright &y& Elsevier]

Pure and Al-doped Zin Oxide ZnO (AZO) thin films with different aluminum (Al) concentrations (0.5, 1, 2, and 3 at.%) were prepared on glass substrates by a dip-coating technique using different Zn and Al precursors. The structural, morphological, optical and electrical properties of these films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Atomic force electron microscopy, ultraviolet–visible spectrophotometry, photoluminescence (PL) spectroscopy and four-point probe technique. XRD results showed that the obtained AZO thin films were polycrystalline with a highly c-axis preferred (002) orientation, and the average crystallites size decreased from 29 to 25 nm with the increase in Al doping concentration. EDS microanalysis confirmed the presence of Zn, O and Al elements in the prepared films as expected. The optical study demonstrated that the ZnO thin film had a good transparency in the visible range with a maximum transmittance of 90% and the band gaps varied from 3.16 to 3.26 eV by Al doping. SEM micrographs showed a wrinkles-like morphology of the thin films that changed in density with the increase of Al concentrations. The PL emission spectra indicated that except the thin film doped with 1 at.%, other films exhibited high emission intensities under an excitation of 325 nm which allows to apply them as downconversion layers for solar cell applications. [ABSTRACT FROM AUTHOR]

The study examines the optical and electrical characteristics of n-ZnO:Al (AZO) thin films that were deposited on p-Si using the sol-gel dip-coating process, with thicknesses ranging from three to six cycles. The I-V characteristics of the diode device exhibited a high and low current under forward and reverse bias, respectively. The ideality factors were found to decrease from 2.78 to 2.13 with an increase in the number of layers from 3C to 6C. However, it was revealed that the barrier height increased from 0.72 to 0.79 eV. Similarly, the rectification ratio increased from 3196 at ±4 V to 5253 at ±4 V with an increase in the thickness of the emitter layer. Some diode parameters were calculated according to the thermionic and Chueng models and found to be in a range comparable to the literature. The optical study based on photoluminescence under UV excitation showed typical emission spectra of n-AZO/-Si heterostructure characterized by a high emission band around 389 nm, which is due to the recombination of excitons (e-=h+). The various intrinsic defects present in ZnO-doped Al thin films are attributed to the broad emission band in the visible range. The chromaticity study with color properties indicated that the correlated color temperature value of the sample 3C (1380 K) falls in the warm white light region. However, the correlated color temperature value of sample 6C (4454 K) is located in the cool white light source region, which is more suitable as an LED lighting source. It was found that by increasing the emitter layer thickness, the correlated color temperature value of the 6C sample is getting closer to 6504 K - the Commission Internationale de l'Eclairage (CIE) standard for daylight (D65). However, unlike the Duv value of the 6C sample (0.011), the one of the 3C sample (0.0032) is located within the acceptable shift range (±0:006). Based on this study, these heterostructures might be an appealing option for manufacturing W-LEDs with n-UV/blue LED chips as the excitation source for use in displays and lighting. [ABSTRACT FROM AUTHOR]

Abstract: This work presents the effect of postdeposition annealing on the structural, electrical and optical properties of undoped ZnO (zinc oxide) thin films, prepared by radio-frequency sputtering method. Two samples, 0.17 and 0.32 µm-thick, were annealed in vacuum from room temperature to 350 °C while another 0.32 µm-thick sample was annealed in air at 300 °C for 1 h. X-ray diffraction analysis revealed that all the films had a c-axis orientation of the wurtzite structure normal to the substrate. Electrical measurements showed that the resistivity of samples annealed in vacuum decreased gradually with the increase of annealing temperature. For the 0.32 µm-thick sample, the gradual decrease of the resistivity was essentially due to a gradual increase in the mobility. On the other hand, the resistivity of the sample annealed in air increased strongly. The average transmission within the visible wavelength region for all films was higher than 80%. The band gap of samples annealed in vacuum increased whereas the band gap of the one annealed in air decreased. The main changes observed in all samples of this study were explained in terms of the effect of oxygen chemisorption and microstructural properties. [Copyright &y& Elsevier]

Cd x Zn 1-x S thin films have been deposited on glass substrates by simple and cost-effective chemical method i.e. Chemical Bath Deposition (CBD) for their potential applications in photovoltaics. The structural, morphological, chemical and optical properties of deposited thin films were investigated by X-ray Diffraction, Scanning Electron Microscopy, UV–vis and Raman spectrometry. Structural properties revealed that deposited thin films exhibit both cubic and hexagonal crystal structure. The Cd x Zn 1-x S thin films with grain size between 6−25 nm exhibit transmittance from 50 to 80% in the visible region. The optical band gap energy of deposited thin films was observed to be in the range from 2.6 to 3.6 eV illustrating their potential viability for optoelectronic and photovoltaic devices. [ABSTRACT FROM AUTHOR]

• The present work is an important issue to optimize the CZTS solar cell performance. • We've first make an experimental study of the CZTS thin film which it's prepared by sol gel dip coating technique. • Used of the experimental parameters obtained by the experience on the numerical study. • By Scaps-1D we study the effect of the active layer thickness on the performance of the studied cell, and also the effect of, shallow acceptor density and work temperature. This work aims to study the basic Characteristics of CZTS thin films produced by chemical solution process in addition to a numerical study of the CZTS-based solar cells. In this context, eco-friendly and cost effective thin films of CZTS were coated on glass substrates by sol–gel dip-coating method. This method is used to grow crystalline CZTS thin films without sulfidation processes. The structural and optical properties have been carried out by X-ray Diffraction (XRD) and UV/Visible spectroscopy. The oxidation states of CZTS thin film have been studied by, X-ray photoelectron spectroscopy XPS analysis. The performance of CZTS solar cells has been investigated with the simulator SCAPS-1 D. The impact of different parameters like the CZTS absorber layer thickness, the carrier doping density and the operation temperature has been studied to get better understanding of the properties of our cells. [ABSTRACT FROM AUTHOR]

Abstract: Undoped ZnO thin films of different thicknesses were prepared by r.f. sputtering in order to study the thickness effect upon their structural, morphological, electrical and optical properties. The results suggest that the film thickness seems to have no clear effect upon the orientation of the grains growth. Indeed, the analysis with X-ray diffraction show that the grains were always oriented according to the c(002)-axis perpendicular to substrate surface whatever the thickness is. However, the grain size was influenced enough by this parameter. An increase in the grain size versus the thickness was noted. For the electrical properties, measurements revealed behaviour very dependent upon thickness. The resistivity decreased from 25 to 1.5×10−3 Ωcm and the mobility increased from 2 to 37cm2 V−1 s−1 when the thickness increased from 70 to 1800nm while the carrier concentration seems to be less affected by the film thickness and varied slightly remaining around 1020 cm−3. Nevertheless, a tendency to a decrease was noticed. This behaviour in electrical properties was explained by the crystallinity and the grain size evolution. The optical measurements showed that all the samples have a strong transmission higher than 80% in the visible range. A slight shift of the absorption edge towards the large wavelengths was observed as the thickness increased. This result shows that the band gap is slightly decreases from 3.37 to 3.32eV with the film thickness vary from 0.32 to 0.88μm. [Copyright &y& Elsevier]

In this work, we have optimized a CZTS-based solar cell using solar cell capacitance simulator (SCAPS-1D). We particularly focused on replacing the buffer layer, which is conventionally CdS-based, with a non-toxic and abundant material. To this end, we have made a comparative study with 3 materials (CdS, SnS 2 , Zn 2 SnO 4) by evaluating the photovoltaic parameters (Short-circuit current density, open circuit voltage, Fill Factor and efficiency) as a function of the buffer layer thickness. We also studied the effect of the active layer thickness on the performance of the cell, in correlation with different materials used for buffer layer elaboration. We concluded that SnS 2 is the best candidate to replace CdS, which was considered until now the most suitable material. We thus obtained an efficiency of 12.73% with the structure glass/Mo/CZTS/SnS 2 /ZnO by avoiding any toxic product and by reducing the thickness of buffer layer to 50 nm. [ABSTRACT FROM AUTHOR]