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Quaternary compound Cu2ZnSnS4 (CZTS) is widely recognized as a promising candidate for use as an absorber layer for photovoltaic applications. However, its efficiency is limited by the high density of antisite defects that shorten the performance of CZTS-based solar cells. Cation substitution of copper by other elements has been proposed as a potential solution in order to control and eliminate the cation disorder within the kesterite structure. In this work, Ag2ZnSnS4 (AZTS) and Cu2ZnSnS4 (CZTS) powders were successfully synthesized by solid state reaction. XRD and Raman measurements were performed to study the crystallographic structures and their lattice vibration spectrum. The results confirmed the presence of the pure phase of CZTS and the stannite phase of AZTS with an occurrence of the secondary phase Ag8SnS6. Morphological properties and the composition analysis of synthesized powders were analyzed by scanning electron microscopy and energy dispersive x-ray analysis. A significant change is noticed in the band gap energy value established by the diffuse reflectance spectroscopy from 1.44 eV for CZTS to 2.55 eV for AZTS. Lastly, measurements with the hot probe method indicate the p-type conductivity of CZTS and the n-type conductivity for AZTS as predicted by theoretical studies. These results highlight that the substitution of silver for copper in CZTS leads to significant changes in the properties of CZTS.

In this work, we report the structural, electrical, and optical properties of nontoxic and earth-abundant Na2ZnSnS4 (NZTS) material. NZTS powder has been successfully synthesized using an easy and nontoxic pathway: the solid-state reaction technique. X-ray diffraction, transmission electron microscopy, and Raman spectroscopy were used to study the structural properties of the NZTS. The synthesized powder crystallized in the stannite tetragonal structure with lattice parameters a = 6.48 A and c = 9.12 A. XRD and Raman characterizations showed the occurrence of the secondary phase Na4SnS4. Optical bandgap measurements were obtained from UV–Visible analysis and showed a high optical bandgap value of 3.32 eV and confirmed the presence of Na4SnS4. TEM micrographs provide a description of the morphology of NZTS. The HRTEM images reflect a preferred orientation along the {112} plane, which is consistent with the X-ray diffraction pattern. EDS analysis confirmed the presence of the four constituent elements of the NZTS within their corresponding composition. NZTS powder indicates a conductivity type n. A study of electrical conductivity was carried out by using the impedance spectroscopy. The frequency and temperature dependence of the complex electrical impedance and AC and DC conductivity were explored. These interesting results make the NZTS particularly attractive for solar cell applications and especially suitable as a window layer.

Earth abundant Cu2ZnSnS4 (CZTS) films were grown by thermal evaporation technique onto non heated substrates. As deposited CZTS films were annealed under two different atmospheres: (1) vaccum annealing atmosphere and (2) sulfur annealing atmosphere followed by vacuum annealing. The samples were analyzed for their microstructural, electrical and optical properties before and after annealing. X-Ray Diffraction (XRD) analysis revealed that the as deposited film was amorphous whereas the annealed ones were polycrystalline with a highly (1 1 2) orientation. Raman spectroscopy confirmed the phase purity of annealed CZTS films. Both annealing atmospheres were found to decrease the band gap energy and the resistivity of the samples. All films exhibited p-type electrical conductivity. Numerical simulation of earth abundant CZTS thin film solar cells with non toxic Zn(S,O) buffer layer was performed by Solar Cell Capacitance Simulator (SCAPS-1D) using the experimental results obtained for CZTS and Zn(S,O) films. Zn(S,O) was used to substitute toxic CdS in earth-abundant Cd-free CZTS solar cells. A maximum conversion efficiency of 12.60% was obtained for Mo/p-Cu2ZnSnS4/n-Zn(S,O)/i-ZnO/n-ZnO:Al structure with CZTS film annealed under sulfur annealing atmosphere followed by vacuum annealing.

Sb2S3 films were deposited on unheated glass substrates by thermal evaporation and annealed under vacuum atmosphere for 2 hours at different temperatures. Different characterization techniques were used to better understand the behavior of the Sb2S3 material. XRD and Raman spectroscopy confirmed the formation of pure Sb2S3 powder with orthorhombic lattices. The effect of vacuum annealing on the properties of the films was studied. XRD analysis revealed that as-deposited and annealed films at 150ºC were amorphous in nature whereas those annealed at T ≥ 200°C were polycrystalline. The crystallite size of the films showed a decrease from 75.8 to 62.9 nm with the increase of the annealing temperature from 200 to 250 °C. The Raman showed several peaks corresponding to the stibnite Sb2S3 phase. The surface morphology of the films was examined by AFM. The roughness decreases slightly as the transformation from the amorphous to the crystalline phase occurs. The chemical compositions of Sb2S3 films were analyzed by EDS, revealing that all films were Sb-rich. The optical parameters were estimated from the transmittance and reflectance spectra recorded by UV-Vis spectroscopy. A reduction in the band gap energy from 2.12 to 1.70 eV with the increase of annealing temperature was also found., E. Gnenna acknowledges the Tunisian Ministry of Higher Education and Scientific Research for providing a two-month internship at the ICMAB-CSIC Institute (Barcelona-Spain). N. Khemiri also thanks the Tunisian Ministry of Higher Education and Scientific Research for support through the PEJC Young Researchers Encouragement Program (Project code 19PEJC03-11). M. Kong is grateful to the UAB PhD programme in Materials Science in which she is enrolled and the China Scholarship Council for funding (CSC No. 201809370071). M.I.A. thanks the Spanish Ministry (MICINN) for support through grant CEX2019-000917-S (FUNFUTURE) and the Catalan agency AGAUR for grant 2017-SGR-00488. The Scientific and Technical Services of ICMAB are gratefully acknowledged for AFM and SEM measurements.

International audience; (SnS)m(Sb2S3)n thin films were prepared by thermal evaporation using the glancing angle deposition technique (GLAD). The incident angle between the particle flux and the normal to the substrate was fixed at 80°. The Raman and XRD characterization revealed the amorphous character of the films due to the columnar structure as shown by the SEM characterization and AFM analysis. A strong change of the surface morphology of the films was observed and it depends on the composition. Optical properties were extracted from transmittance T and reflectance R spectra. (SnS)m(Sb2S3)n thin films exhibit high absorption coefficients (104–2 × 105 cm−1) in the visible range and the higher values were obtained for Sn3Sb2S6 and it has the highest photocurrent values. The direct band gap (Eg dir) was in the range 2.11–1.67 eV. The refractive indices are calculated from optical transmittance spectra of the films. The Sn3Sb2S6 sample exhibits a lower refractive index. All the dispersion curves of refractive index match well with the Cauchy dispersion formula and they were analyzed using Wemple-DiDomenico model. The Bruggeman effective medium approximation EMA was used to calculate the packing density of different compositions, and SnSb4S7 sample has the highest value. The so-called Verdet coefficient was evaluated from refractive index dispersion, and it was enhanced near the band gap.

Zn(S,O) thin films was elaborated by annealing in air and sulfur atmospheres the zinc films deposited by thermal evaporation method. The samples were analyzed for their optical properties by using Ultraviolet–Visible-near Infrared spectroscopy. The optical constants and the dispersion parameters of the films were calculated from the analysis of the transmittance and reflectance data in the spectral range 300–1800 nm. The band gap energy varied from 3.27 to 3.08 eV depending on the sulfur content. The bowing parameter was calculated as 2.45 eV. Swanepoel model was employed to study the wavelength dependence of the refractive index. The lattice dielectric constant eL, the plasma frequency ωp and the ratio of the carrier density to the carrier effective mass N/m* were calculated from the examination of the refractive index. Wemple-Di Domenico single oscillator model was applied to determine the dispersion parameters of the samples such as the high-frequency dielectric constant e∞, the oscillator energy E0 and the dispersion energy Ed.

Tin antimony sulfide (TAS) is one of the most promising compounds for the next generation of optoelectronic and thin film photovoltaic devices. TAS material was synthesized by a solid-state reaction using earth-abundant tin, antimony and sulfur elements. The structural properties of the TAS powder were investigated by transmission electron microscopy (TEM). X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and selected electron diffraction (SAED) were employed to establish the crystalline nature of the powder. The TEM observations demonstrated that the powder was polycrystalline in nature with rod-shaped structure. The effects of excimer laser annealing (ELA) at different pulse energies on the structural, morphological and optical properties of thermally evaporated TAS films were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy measurements showed that the films annealed by an excimer laser of 248 nm were amorphous for weak energy densities whereas the sample irradiated with 111 mJ/cm− 2 was polycrystalline with a preferential $${\text{(}}\overline {{\text{2}}} {\text{1}}\overline {{\text{3}}} {\text{)}}$$ orientation. The ELA effects on the optical properties were also studied in the wavelength range 300–1800 nm by using UV–Vis–NIR spectroscopy. The absorption coefficient of all samples in the fundamental absorption region is higher than 104 cm−1. We also found that the optical band gap decreases from 2.04 to 1.84 eV after irradiating the thin films under different laser energy densities.

Milled powder of ordered defect compound (ODC) CuIn3Se5 phase was successfully synthesized via milling process. Thin films of CuIn3Se5 were deposited onto glass substrates at room temperature by thermal evaporation technique. The obtained layers were annealed in vacuum and air atmosphere. The structural and compositional properties of the powder were analyzed using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Powder XRD characterization, Rietveld analysis and chemical bounding confirm the tetragonal ordered defect compound phase formation with lattice constants a = 5.732 A and c = 11.575 A. Thin films were characterized by XRD, atomic force microscopy (AFM) and UV/Vis spectroscopy. Transmittance (T) and reflectance (R) spectra were measured in the spectral range of 300–1800 nm. The absorption coefficient α exhibits high values in the visible range and reaches a value of 105 cm−1. The band gap energy Eg of the annealed thin films is estimated to be approximately 1.75 eV. The refractive index n was estimated from transmittance data using Swanepoel's method. The refractive indices of the films as a function of wavelengths can be fitted with Cauchy dispersion equation. The oscillator energy E0, dispersion energy Ed, zero frequency refractive index n0, high frequency dielectric constant e∞ and the carrier concentration per effective mass N/m∗ values were determined from the analysis of the experimental data using Wemple-DiDomenico and Spitzer-Fan models. We exploited the refractive index dispersion for the determination of the magneto-optical constant V, which characterizes the Faraday rotation. The nonlinear optical parameters namely nonlinear susceptibility χ(3), nonlinear refractive index and nonlinear absorption coefficient β are investigated for the first time for CuIn3Se5 material.

In order to prepare thin films of novel semiconductor materials that contain only earth abundant, low cost and nontoxic elements, Cu 2 Zn x Fe 1-x SnS 4 ingots were successfully synthesized by direct fusion method. Crushed powders of these ingots were used as raw materials for the thermal evaporation. Cu 2 Zn x Fe 1-x SnS 4 (with x = 0, 0.25, 0.5, 0.75 and 1) thin films were deposited on non-heated glass substrates by vacuum evaporation method. The as deposited films were sulfurized for 30 min at sulfurization temperature T s = 400 °C. The effects of the sulfurization on the structural and optical properties of CZFTS films were realized by X-ray diffraction (XRD) and UV–Vis spectroscopy. XRD patterns show that all sulfurized CZFTS films were polycrystalline in nature with a preferential orientation along the (112) plane. CFTS films exhibit a stannite structure while CZTS films had a kesterite structure. Optical measurements showed that CZFTS films sulfurized at 400 °C exhibited an optical transmittance between 60 and 80% and all materials had relatively high absorption coefficients in the range of 10 4 –10 5 cm −1 . The band gap energies of sulfurized CZFTS films decreased from 1.71 to 1.50 eV with the increase of the Zn content. The dispersion of the refractive index was discussed in terms of the single oscillator model proposed by Wemple and DiDomenico and the optical parameters such as refractive index, extinction coefficient, oscillator energy and dispersion energy were calculated. The electrical free carrier susceptibility and the carrier concentration on the effective mass ratio were evaluated according to the model of Spitzer and Fan. The hot probe analysis showed that all sulfurized CZFTS films are p -type conductivity.

Zn(S,O) thin films were grown by three step process: (1) the deposition of Zn layer on glass substrates by vacuum thermal evaporation, (2) the oxidation of the as-deposited Zn layer in air atmosphere and (3) the sulfurization of the oxidized samples in N 2 atmosphere. The samples were analyzed for their microstructural, morphological and optical properties. XRD analysis revealed that the films were polycrystalline with a highly c -axis orientation. EDX measurements suggested that the sulfur content of the films could be inflected by the sulfurization temperature. The optical constants of the films were calculated from the analysis of the transmittance and reflectance data. The band gap energy varied from 3.27 to 3.08 eV depending on the sulfur content. The surface morphological studies revealed that the films had an average roughness between 13.1 and 16.9 nm. Zn(S,O) thin films exhibited n-type electrical conductivity.

Bi2Se3 powder has been successfully synthesized via mechanical ball milling of bismuth and selenium as starting materials. X-ray diffraction characterization revealed the formation of the rhombohedral and orthorhombic phases of Bi2Se3 material belonging to systems with space groups \( {\hbox{R}}\bar{3}{\hbox{m}}\) and Pbnm, respectively. The advantageous last finding is confirmed by the Rietveld refinement of the x-ray diffraction data. Furthermore, the analysis of the x-ray data of thermally deposited thin films revealed that both orthorhombic and rhombohedral phases are coexisting in the layer. The morphology of the ball milled powder was studied by scanning electron microscopy. The phase formation of the material is confirmed by Raman spectroscopy. M–H (Magnetization versus Magnetic field) curve indicates that Bi2Se3 powder has a ferromagnetic behavior. Additionally, absorbance and transmittance measurements were carried out on the obtained thermally evaporated thin films and yielded a band gap of 1.33 eV supporting the potential application of the heterogeneous rhombohedral/orthorhombic Bi2Se3 material in photovoltaics.

In order to study the Zinc Tin Oxide (ZTO) as an alternative buffer layer to replace CdS in thin films solar cells, we synthesized the (Zn,Sn)O material using the vacuum thermal evaporation of the metal compounds, Tin and Zinc, followed by annealing treatments. The obtained samples were divided into two groups according to the amount of Tin used during the thermal evaporation while the amount of Zinc remains invariant. The first group of ZTO thin films was made using a Tin amount of 0.312 g and annealed in air at different temperatures (samples A). The second group was made using a less amount of Tin (0.156 g) (samples B). Part of these samples were annealed in air atmosphere (samples B1) whereas the other sample was annealed under vacuum then annealed in air (sample B2). The annealing process was mainly dedicated to the oxidation treatment of Sn/Zn metallic bilayers but it also plays an important role to improve the crystallinity of the as-deposited films. The structural, optical and electrical properties of the prepared films were characterized using X-ray diffraction, UV–VIS–NIR spectrophotometry and impedance spectroscopy, respectively. We have succeeded to obtain a stable cubic spinel structure of Zn2SnO4 phase (sample B2). This thin film showed interesting properties such as a direct band gap energy of value of 3.20 eV, a high optical transmission of 80% and a n-type electrical conductivity.

In this study, we report the structural and morphological properties of the new material Sn2Sb6S11 thin films prepared on glass substrates by vacuum thermal evaporation at various substrate temperatures (30, 60, 100, 140, 180 and 200 °C). Sn2Sb6S11 ingot was synthesized by the horizontal Bridgman technique. The structural properties of Sn2Sb6S11 powder were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The films were characterized for their structural properties by using XRD. All films were polycrystalline in nature. The variations of the structural parameters of the films with the substrate temperature were investigated. The results show that the crystallite sizes increase as the substrate temperature increases. The morphological properties of the films were analyzed by atomic force microscopy (AFM). The roughness and the topography of the surface of the films strongly depend on the substrate temperature.

SnSb4S7 thin films were grown on glass substrates by means of the vacuum thermal evaporation technique. The annealing process was performed under nitrogen (N2) atmosphere at different temperatures (Ta) during one hour. The influence of annealing in nitrogen atmosphere on the structural, morphological and optical properties of SnSb4S7 thin films was studied by X-ray diffraction (XRD), Raman spectroscopy, Atomic Force Microscopic (AFM) and UV–Vis spectroscopy, respectively. XRD analysis confirmed the polycrystalline nature of SnSb4S7 films with the monoclinic crystalline phase. We also observed a change in the preferential orientation of the films from ( 4 ¯ 01 ) to the ( 2 ¯ 11 ) plane by increasing annealing temperature. We also found that the average crystallite size first decreases from 25.3 to 11.3 nm by increasing Ta up to 200 °C and then increases to 49.5 nm for Ta = 300 °C. The Raman spectra of the samples showed several peaks corresponding to the SnSb4S7 phase. The Raman spectroscopy confirmed the results obtained by XRD analysis. Atomic force microscopy studies showed that the change in the film morphology depends on the annealing in N2 atmosphere. Indeed, AFM images indicated the increase of roughness by increasing the annealing temperature above 200 °C. The effects of annealing on the optical properties and dispersion parameters of the films were investigated. It was found that annealing in N2 atmosphere decreases the transmittance of films and affects the absorption coefficient and the optical band gap of the samples. Indeed, the optical energy gap first increases from 1.80 to 1.90 eV up to 200 °C and then decreases to 1.45 eV for Ta = 300 °C. Wemple–DiDomenico and Spitzer–Fan models were used for the analysis of the dispersion of the refractive index and the determination of the optical and dielectric constants.

The SnSb 4 S 7 , SnSb 2 S 4 , Sn 4 Sb 6 S 13 , Sn 2 Sb 2 S 5 and Sn 3 Sb 2 S 6 materials were synthesized by the Bridgmann technique. The five pellets were characterized by X-ray diffraction, Raman spectroscopy and diffuse reflectance spectroscopy. The changes observed in Raman spectra were due to the influence of the composition. Kubelka–Munk model and inversion method were used to determine the band gap energies of the samples. The absorption edges were determined using the first derivative of diffuse reflectance spectra. The band gap varies between 1.17 and 1.06 eV.

In the present work, we report on the synthesis of nano-crystalline kesterite copper zinc tin sulfide (CZTS) in powder form and the post-annealing process at high temperatures (calcination), and study their physical properties. We have successfully synthesized CZTS by direct fusion, and the resulting material was crushed to obtain a fine powder. Then, the resulting powder was calcined at high temperatures: 800–1000 ∘C. The calcined samples have been characterized with a number of different structural: X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and optical techniques: photoluminescence (PL), Raman and diffuse reflectance spectroscopy (DRS). From the XRD analysis we grant that the material presents mainly the kesterite structure and it is polycrystalline, with a preferential orientation along the [112] direction. From XRD, SEM, EDX and Raman spectroscopy, we conclude that the best crystallinity and stoichiometry was obtained for a calcination temperature of 900 ∘C. From te PL and DRS results we deduce that the sample with smaller emission and an energy gap close to 1.5 is that calcined at 900∘. In summary, we can confirm from the present study made with a number structural and optical techniques, that the CZTS has grown in the kesterite structure and the sample calcined at 900∘C has the best crystallinity and the optimum band gap to be used as an absorber in solar cell devices.

International audience; Sb2Se3 powder is achieved by mechanical milling of Sb and Se elements. X-ray diffraction analysis indicated the formation of Sb2Se3 orthorhombic phase. The latter finding is confirmed by both X-ray photoelectron spectroscopy characterization and Raman spectroscopy. Magnetic measurement revealed the ferromagnetic character of Sb2Se3 powder. Thin films were obtained by thermal deposition using Sb2Se3 powder as a precursor. Optical measurements carried out on thin films showed a high absorption coefficient and a direct band gap of 1.61 eV. The material has then potential application in photovoltaic conversion. Thin film refractive index dispersion ( n) obeys Cauchy dispersion equation. n is investigated and found to comply with Wemple-DiDomenico single oscillator dispersion model. The energy E 0 of the oscillator and E d dispersion energy are derived from the refractive index investigation. Spitzer-Fan model exploitation was allowed to derive the high-frequency dielectric constant ɛ ∞ and the carrier density N/ m* ratio. Additionally, Verdet constant V is determined based on the refractive index dispersion study. Furthermore, the nonlinear susceptibility χ (3) as well as nonlinear refractive index are determined for Sb2Se3 thin films. The nanostructure of the material is likely responsible not only for the high nonlinear characteristics but also for the low magnetic character in Sb2Se3.

In this work, SnSb 4 S 7 thin films were prepared by vacuum evaporation method, and the effect of substrate temperature on the structural and optical properties were investigated. Substrate temperature was varied from room temperature to 170 °C. Optical constants such as band gap, absorption coefficient, extinction coefficient, refractive index, and dielectric constant were determined from the measured transmittance and reflectance spectra in the wavelength range between 300 and 1800 nm using the envelope method. The dispersion behavior of the refractive index was studied in terms of the single-oscillator Wemple–DiDomenico (W–D) model, and the physical parameters of the refractive index dispersion and the dispersion energy were found. The electrical free carrier susceptibility and the carrier concentration of the effective mass ratio were estimated according to the Spitzer–Fan model. Furthermore, the optical band gap values were calculated by the W–D model and the Tauc model, respectively. The major result of this study is optical, structural, and dielectric properties of SnSb 4 S 7 could be modified with the different substrate temperature.

In this paper, we report the effect of the substrate temperature on the structural, morphological and optical properties of SnSb4S7 thin films elaborated by thermal evaporation at different substrate temperatures. Spectroscopic techniques like X-ray diffraction (XRD), energy dispersive X-ray (EDX), Raman spectroscopy, Atomic Force Microscopy (AFM) and UV–vis spectroscopy were used to characterize the SnSb4S7 powder and films. The X-ray diffraction analysis revealed that the powder crystallized in monoclinic structure with a preferred orientation along ( 2 ¯ 1 3 ¯ ) plane. The calculated lattice parameters were a=11.51 A, b=4.17 A, c=13.96 A and β=105.41°. SnSb4S7 thin films are polycrystalline in nature and the average grain size increases by increasing the substrate temperature. The Raman spectroscopy shows that the Raman modes for the SnSb4S7 thin films are observed at 105, 117, 140, 150, 250, 187, 303, 371, 400 and 450 cm−1. Atomic Force Microscopy images revealed that the surface roughness of the films decreased from 2.37 nm to 0.785 nm by increasing the substrate temperature. The optical constants of the evaporated films were determined, in the spectral range 300–1800 nm, from the analysis of the transmission and the reflection data. The energy band gap values decreased from 1.77 eV to 1.69 eV with the increase of the substrate temperature. The most significant result of the present study is that the substrate temperature can be used to modify the structural, morphological and optical properties of SnSb4S7 thin films.

CuIn11S17 compound was synthesized by horizontal Bridgman method using high-purity copper, indium and sulfur elements. CuIn11S17 thin films were prepared by high vacuum evaporation on glass substrates. The glass substrates were heated at 30, 100 and 200 °C. The structural properties of the powder and the films were investigated using X-ray diffraction (XRD). XRD analysis of thin films revealed that the sample deposited at a room temperature was amorphous in nature while those deposited on heated substrates were polycrystalline with a preferred orientation along the (311) plane of the spinel phase. Ultraviolet–visible (UV–vis) spectroscopy was used to study the optical properties of thin films. The results showed that CuIn11S17 thin films have high absorption coefficient α in the visible range (105–106 cm−1). The band gap Eg of the films decrease from 2.30 to 1.98 eV with increasing the substrate temperature (Ts) from 30 to 200 °C. We exploited the models of Swanepoel, Wemple–DiDomenico and Spitzer–Fan for the analysis of the dispersion of the refractive index n and the determination of the optical constants of the films. Hot probe method showed that CuIn11S17 films deposited at Ts=30 °C and Ts=100 °C are p-type conductivity whereas the sample deposited at Ts=200 °C is highly compensated.

SnSb 4 S 7 , Sn 2 Sb 6 S 11 , SnSb 2 S 4 , Sn 4 Sb 6 S 13 , Sn 2 Sb 2 S 5 , and Sn 3 Sb 2 S 6 single crystals were grown via the Bridgman technique and Sn x Sb y S z thin films were obtained by a vacuum evaporation method onto non-heated glass substrates. Their structural and optical properties are studied by X-ray diffraction and transmittance and reflectance measurements in the wavelength range 300–1800 nm. X-ray diffraction (XRD) patterns indicate that polycrystalline Sn x Sb y S z films were successfully obtained without heating the substrates. Optical measurements show that thin films of all materials have relatively high absorption coefficients between 10 4 and 2×10 5 cm −1 in the visible range and the higher values were obtained for Sn 2 Sb 2 S 5 thin films. It is also found that the Sn x Sb y S z films exhibit direct and indirect gaps E g d and E g ind which varied from 1.87 to 1.46 eV and from 1.71 to 1.37 eV, respectively. The dispersion behavior of the refractive index was studied in terms of the single-oscillator Wemple–DiDomenico and Cauchy models, and the optical parameters such as refractive index, extinction coefficient, oscillator energy, dispersion energy and Cauchy׳s constants were found. The electrical free carrier susceptibility and the carrier concentration of the effective mass ratio were estimated according to the model of Spitzer and Fan.

CuIn2n+1S3n+2 (where n = 0, 1, 2, 3 and 5) thin films were deposited at different substr ate temperatures (30, 75, 100, 150 and 200 � C) by vacuum evaporation. The films were characterized for their struc tural properties by using X-ray diffraction (XRD). From the XRD data, we calculated the grain size, the lattice strain, the lattice para meters and the dislocation density for the preferential orientation of CuIn2n+1S3n+2 thin films. The effect of the substrate temperature on the structural crys talline quality of the films was also investigated.

In this study, the annealing effect on structural, electrical and optical properties of CuIn 2 n +1 S 3 n +2 thin films ( n =0, 1, 2 and 3) are investigated. CuIn 2 n +1 S 3 n +2 films were elaborated by vacuum thermal evaporation and annealed at 150 and 250 °C during 2 h in air atmosphere. XRD data analysis shows that CuInS 2 and CuIn 3 S 5 ( n =0 and 1) crystallize in the chalcopyrite structure according to a preferential direction (112), CuIn 5 S 8 and CuIn 7 S 11 ( n =2 and 3) crystallize in the cubic spinel structure with a preferential direction (311). The optical characterization allowed us to determine the optical constants (refractive indexes 2.2–3.1, optical thicknesses 250–500 nm, coefficients of absorption 10 5 cm −1 , coefficients of extinction

CuIn 5 S 8 thin films were prepared by thermal evaporation under vacuum onto heated and no heated glass substrates. These films were characterized for their structural, optical and electrical properties by using X-ray diffraction (XRD), optical measurement and Hall-effect measurements. X-ray diffraction analysis of the deposited films revealed that the film deposited without heating the substrate was amorphous in nature and an amorphous-to-crystalline phase transition with could be obtained by heating the substrates above 100 °C. The optical constants of the deposited films were determined, in the spectral range 300–1800 nm, from the analysis of the transmission and reflection data. The energy bandgap values changed from 2.17 to 1.77 depending on the substrate temperature. The refractive index dispersion and extinction coefficient in the low absorption region are adequately described by the Wemple–Di Domenico single oscillator model. The values of the oscillator energy E 0 , dispersion energy E d , the high-frequency dielectric constant e ∞ and the ratio of the carrier concentration to the effective mass were estimated according to the models of Wemple–Di Domenico and Spitzer–Fan. The resistivity values of the films increased from 0.826 to 1.495×10 6 Ω cm and a transition from p-type conductivity to a highly compensated state is observed by increasing the substrate temperature

CuIn2n+1 S3n+2 crystals were synthesized by horizontal Bridgman method using high purity copper, indium, sulfur elements. The phases and crystallographic structure of the CuIn2n+1S3n+2 crystals were analyzed by X-ray diffraction (XRD) and the composition of the material powders was determined using the energy dispersive X-ray analysis (EDX). Measurement data revealed that CuIn2n+1S3n+2 materials have not the same structure. In fact, CuInS2 and CuIn3S5 crystallize in the chalcopyrite structure whereas CuIn5S8, CuIn7S11 and CuIn11S17 crystallize in the cubic spinel structure.

CuInS 2 , CuIn 3 S 5 , CuIn 5 S 8 and CuIn 7 S 11 compounds were synthesized by the horizontal Bridgman method using high-purity copper, indium and sulphur elements. Crushed powders of these ingots were used as raw materials for the vacuum thermal evaporation. So, CuIn 2n + 1 S 3n + 2 (n = 0, 1, 2, and 3) thin films were deposited by single source vacuum thermal evaporation onto glass substrates heated at 150 °C. The structural, compositional, morphological, electrical and optical properties of the deposited films were studied using X-ray diffraction (XRD), energy dispersive X-ray, atomic force microscopy and optical measurement techniques. XRD results revealed that all the films are polycrystalline. However, CuInS 2 and CuIn 3 S 5 films had a chalcopyrite structure with preferred orientation along 112 while CuIn 5 S 8 and CuIn 7 S 11 films exhibit a spinel structure with preferred orientation along 311. The absorption coefficients of the all CuIn 2n + 1 S 3n + 2 films are in the range of 10 −4 and 10 −5 cm −1 . The direct optical band gaps of CuIn 2n + 1 S 3n + 2 layers are found to be 1.56, 1.78, 1.75 and 1.30 eV for n = 0, 1, 2, and 3, respectively. CuIn 3 S 5 and CuIn 5 S 8 films are p type with electrical resistivities of 4 and 12 Ω cm whereas CuInS 2 and CuIn 7 S 11 are highly compensated with resistivities of 1470 and 1176 Ω cm, respectively.

CuIn 3 S 5 thin films were prepared from powder by thermal evaporation under vacuum (10 −6 mbar) onto glass substrates. The glass substrates were heated from 30 to 200 °C. The films were characterized for their optical properties using optical measurement techniques (transmittance and reflectance). We have determined the energy and nature of the optical transitions of films. The optical constants of the deposited films were determined in the spectral range 300–1800 nm from the analysis of transmission and reflection data. The Swanepoel envelope method was employed on the interference fringes of transmittance patterns for the determination of variation of refractive index with wavelength. Wemple–Di Domenico single oscillator model was applied to determine the optical constants such as oscillator energy E 0 and dispersion energy E d of the films deposited at different substrate temperatures. The electric free carrier susceptibility and the ratio of the carrier concentration to the effective mass were estimated according to the model of Spitzer and Fan.

CuIn 3 S 5 and CuIn 7 S 11 powders were prepared by solid-state reaction method using high-purity elemental copper, indium and sulphur. The films prepared from CuIn 3 S 5 and CuIn 7 S 11 powders were grown by thermal evaporation under vacuum (10 −6 Torr) on glass substrates at different substrate temperature Ts varying from room temperature to 200 °C. The powders and thin films were characterized for their structural properties by using X-ray diffraction (XRD) and energy dispersive X-ray (EDX). Both powders were polycrystalline with chalcopyrite and spinel structure, respectively. From the XRD data, we calculated the lattice parameters of the structure for the compounds. For CuIn 3 S 5 powder, we also calculated the cation–anion bond lengths. The effect of substrate temperature Ts on the structural properties of the films, such as crystal phase, preferred orientation and crystallinity was investigated. Indeed, X-ray diffraction analysis revealed that the films deposited at a room temperature (30 °C) are amorphous in nature while those deposited on heated were polycrystalline with a preferred orientation along (1 1 2) of the chalcopyrite phase and (3 1 1) of the spinel phase for CuIn 3 S 5 and CuIn 7 S 11 films prepared from powders, respectively. The morphology of the films was determined by atomic force microscopy AFM. The surface roughness and the grain size of the films increase on increasing the substrate temperature.

CuIn3S5 compound was prepared by direct reaction of high-purity elemental copper, indium and sulphur. CuIn3S5 thin films were prepared from powder by thermal evaporation under vacuum (10−6 mbar) onto glass substrates. The glass substrates were heated from 30 to 200 °C. The powder was characterized for their structural and compositional properties by using X-ray diffraction (XRD) and energy dispersive X-ray (EDAX). The XRD studies revealed that the powder exhibiting P-chalcopyrite structure. From the XRD data, we calculated the lattice parameters a and c. Then, the cation–anion bond lengths lAC and lBC are deduced. The films were characterized for their structural, compositional, morphological and optical properties by using XRD, EDAX, atomic force microscopy and optical measurement techniques (transmittance and reflectance). XRD analysis revealed that the films deposited at a room temperature (30 °C) are amorphous in nature, whereas those deposited on heated substrates (≥75 °C) were polycrystalline with a preferred orientation along (112) of the chalcopyrite phase. The surface morphological analysis revealed that the films grown at different substrate temperature had an average roughness between 1.1 and 4.8 nm. From the analysis of the transmission and reflection data, the values of direct and indirect band gap of the films were determined. We found that the optical band gap decreases when the substrate temperature increases.

We report in this paper the preparation and characterization of Cu–In–O films. The samples were prepared by an annealing at 200 °C for 2 h in vacuum followed by an annealing at 400 °C for 3 h in air atmosphere (sample A) and directly by an annealing at 400 °C for 3 h in air atmosphere (sample B). The films were characterized for their structural, surface morphological, compositional, electrical and optical properties by using X-ray diffraction (XRD), scanning electron microscopy, electrical conductivity and optical measurement techniques (transmittance and reflectance). The XRD patterns revealed the presence of CuO and In2O3 phases. The absorption coefficients of Cu–In–O thin films in both cases are in the range (104–105) cm–1 and the direct optical band gaps are 3 eV and 3.55 eV for the samples B and A, respectively. The electrical measurements show a conversion from a metallic phase to a semiconductor phase. n-type conductivity was found for the sample B, whereas the sample A was highly resistive. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We report in this paper on the preparation and characterization of improved quality Cu–In–O films for use as a high-efficiency solar cell absorber. Samples were prepared via sequential thermal vacuum deposition of Cu and In or In and Cu (at 10 −5 mbar) on glass substrates heated at 150°C. After what, the obtained binary systems (Cu/In or In/Cu) were annealed in air at 400°C for 3h. These films were characterized for their structural, electrical and optical properties by using X-ray diffraction (XRD), electrical resistivity and optical (transmittance and reflectance) measurement techniques. The X-ray diffraction (XRD) patterns revealed the presence of CuO and In 2 O 3 phases. The absorption coefficient of Cu–In–O thin films (4.10 5 cm −1 ) is larger than 10 5 cm −1 for the In/Cu case and in the range of 10 4 –10 5 cm −1 for the Cu/In case in the visible spectral range. Direct optical band gaps of 1.40 and 1.52eV were found for the In/Cu and Cu/In cases, respectively. The complex dielectric constants of the Cu–In–O films have been calculated. It was found that the refractive index dispersion data obeyed the Wemple–Di Domenico single oscillator model, from which the dispersion parameters and the high-frequency dielectric constant were determined. The electric free carrier susceptibility and the ratio of the carrier concentration to the effective mass were estimated according to the model of Spitzer and Fan. The electrical measurements show a conversion from a metallic phase to the semiconductor phase by a switching in the electrical resistivity values at an annealing temperature of 275°C. In both cases the samples were highly compensated.

Genetic diversity within Vicia faba L. is key to the genetic improvement of this important species. In this study, morphological traits and RAPD molecular markers were used to assess the levels of polymorphism across 12 Tunisian populations, three major and nine minor from different locations. Analysis of morphological traits indicated that the three major populations showed significant differences and the nine minor populations exhibited considerable variation for most traits. The grain yield of the Alia population could be increased by inoculation. Of the seven primers tested, it was clear that the Cs12 primer would be recommend for genetic diversity analysis of V. faba.Within population genetic diversity exhibited 94% of total diversity. Intra-population genetic diversity (HS) was 0.16, which was clearly higher than between population genetic diversity (DST = 0.06) UPG-MA showed a high level of genetic variation between major and minor populations of V. faba L. Particularly the minor populations showed a high level of diversity and was divided into two subclusters. Ltaifia was separated from the other populations. In addition to a high grain yield, these populations showed the lowest Nei and Shannon indices (H = 0.08 and I = 0.13) justifying their homogeneity. For these reasons, these cultivars can be considered a selected population. However, the Takelsa population showed the highest Nei and Shannon indices (H = 0.13 and I = 0.21), indicating that this population was the most heterogeneous, which is interesting for breeding programs.

The electrical potential technique was applied to detect and locate impact damage in carbon fibre reinforced polymer (CFRP) plates of Hexcel T300/914 composite. The potential field across the surface of the laminates was measured using arrays of electrical contacts. A constant current of 100 mA was applied to the plate, and the changes in the potential distribution resulting from impact damage documented. These results have been compared with those calculated using 3D finite element simulation of current flow in CFRP laminates. The results show good agreement between simulation and experimental results and will permit detailed analytical studies of optimum network and current input configurations for the practical realization of a damage sensing system. A comparison of potential distribution on the top surface for damaged and undamaged laminates shows a substantial difference in the potential field around the impact damaged area. This could form the basis of a damage detection system.

Sn 2m−4 Sb 4 S 2m+2 (m = 2.5, 3 and 4) thin films were deposited on glass and Si substrates using vacuum evaporation technique. The structural properties have been investigated by X-ray diffraction (XRD) and Raman spectroscopy. The XRD patterns revealed the polycrystalline nature of the films on substrates even when they are not heated during evaporation process. Raman spectra revealed four main peaks. The main structural units of Sn–Sb–S thin films are tetrahedral [SnS 4 ] and pyramidal [SbS 3 ]. The cross-section morphology was obtained by scanning electron microscopy (SEM). Spectroscopic ellipsometry (SE) measurements ( ψ and Δ) were carried out to study the optical properties of the films. SE measured data were analyzed by considering double layer optical model for all the samples, with the two oscillators Tauc-Lorentz and Gaussian dispersion relations. Surface roughness was taken into consideration as shown in SEM micrographs. From the ellipsometric study, we determined the thicknesses of the modeled layers and their optical parameters (refractive index, absorption coefficient …). All the films exhibit high absorption coefficient α in the visible range (>10 5 cm −1 ). The values of the band gap energy E g of Sn 2m−4 Sb 4 S 2m+2 thin films deposited on glass were 1.52, 1.29 and 1.28 eV, respectively for m = 2.5, 3 and 4. For the samples deposited on silicon, E g (SnSb 4 S 7 ) = 1.29 eV, E g (SnSb 2 S 4 ) = 1.13 eV and E g (Sn 2 Sb 2 S 5 ) = 1.48 eV.

International audience; CuInS2, CuIn3S5 and CuIn5S8 films were grown by thermal evaporation using oblique angle deposition technique. During the deposition, the substrate temperature was maintained at Ts = 150 degrees C and the deposition angle was fixed at alpha = 0 degrees and 85 degrees. The powders and thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). From the XRD data of powders, we calculated the lattice parameters of the structure for the different compounds. XRD patterns of thin films revealed that all samples deposited at a = 0. were polycrystalline. Indeed, CuInS2 and CuIn3S5 films had a chalcopyrite structure with preferred orientation along (1 1 2) while CuIn5S8 films exhibit a spinel structure with preferred orientation along (3 1 1). However, CuIn2n+1 S3n+2 with n = 0, 1 and 2 films deposited at a = 85. were amorphous in nature. The surface and cross-section of the films were observed by AFM and SEM. The oblique angle deposition films showed an inclined columnar structure, with columns tilting in the direction of the incident flux. The surface roughness of the different films deposited, respectively, at a = 0 degrees and 85 degrees was determined by two methods (AFM and spectrophotometric analysis). The obtained values show an increase of the surface roughness by increasing the deposition angle a.

Many techniques are in development to detect and quantify damage in Carbon Fiber Reinforced Polymers (CFRP) structures. All the techniques have advantages and disadavantages in accuracy, expense, robustness and level of instrumentation. Almost all involve sensing of strains or acoustic waves using embedded or surface mounted optic fibesr or piezo transducers. An alternative, relatively unexplored, is the electrical potential technique, whcih exploits the electical conducitivyt of carbon fiber as a damage sensing element. The technique consists of measurement of potential distribution in CFRP laminates before and after delamination damage is formed by an impact or other event.

Introduction La retinopathie pigmentaire (RP) est caracterisee par sa triple heterogeneite : clinique, genetique et moleculaire. Le but du travail est de degager les principales caracteristiques cliniques et genetiques des RP. Materiels et Methodes Il s’agit d’une retrospective portant sur 36 patients issus de 9 familles originaires de la region du Cap-Bon (Tunisie), atteinte des RP non syndromique. Tous nos patients ont beneficie d’un examen ophtalmologique et general complete par des explorations para-cliniques et d’une etude genetique. Discussion Nos resultats cliniques ont revele une grande heterogeneite. En effet, trois formes cliniques en fonction de l’âge de debut ont ete retrouvees : la RP de la premiere enfance, la RP a debut precoce et la RP classique. Trois formes cliniques en fonction des donnees du FO ont egalement ete identifiees : RP a spicules, retinopathie ponctuee albescente et RP avec mottes pigmentaires. Les complications a type de cataracte et d’œdeme maculaire cystoide etaient presentes, dans respectivement 52 % et 11 % des cas. L’analyse des arbres genealogiques a conclu a un mode de transmission autosomique recessif dans 8 familles et autosomique dominant dans une famille. L’etude moleculaire (analyse de liaison genetique et sequencage de l’ADN) a mis en evidence la mutation R91W sur le gene RPE65 chez tous les individus atteints appartenant a deux familles avec phenotype de RP de la premiere enfance et avec au FO des mottes pigmentaires, suggerant ainsi une correlation phenotype-genotype. Les genes RHO, RDS, ABCA4 et ROM1 ont ete exclus. Conclusion Dans la majorite des RP, on ne retrouve pas de correlation phenotypegenotype evidente, ce qui ne facilite pas la caracterisation du defaut moleculaire responsable de ces pathologies. Toutefois, devant tout patient atteint de RP et rapportant une histoire familiale d’hesperanopie, une enquete genetique et moleculaire s’impose en vue de therapie future.

But Rapporter un cas de keratoconjonctivite gigantopapillaire compliquee d’ulcere corneen bilateral resistant aux traitements locaux et generaux habituels et discuter les modalites therapeutiques. Objectifs et Methodes Enfant âge de 8 ans, consultant pour photophobie et larmoiement bilateraux. L’examen ophtalmologique revelait une conjonctivite gigantopapillaire des deux yeux. La cornee etait le siege de keratite ponctuee superficielle diffuse avec un ulcere corneen ovalise marginal superieur recouvert d’une membrane epaisse aux deux yeux. Cet ulcere etait resistant aux traitements habituels. Le patient a beneficie d’un debridement chirurgical de la membrane recouvrant l’ulcere corneen avec mise en place d’une lentille therapeutique. Apres cicatrisation de l’ulcere, une injection de triamcinolone etait realisee en supratarsale. Discussion L’erosion et l’ulcere corneen constituent des complications typiques des formes severes des kerato-conjonctivites vernales et se voient dans 50 % des cas. Les ulceres corneens peuvent presenter des depots inflammatoires a la base de l’ulcere et repondent mal aux traitements habituels. D’ou l’interet d’un traitement chirurgical. Actuellement, plusieurs auteurs traitent les kerato-conjonctivites gigantopapillaires severes et refractaires par l’injection supratarsale de corticosteroides. Conclusion Le traitement chirurgical est parfois necessaire dans les formes severes et refractaires des kerato-conjonctivites atopiques. L’injection de corticosteroides dans la conjonctive supra-tarsale a fait ses preuves dans les conjonctivites gigantopapillaires.