Publications Internationales
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Item Characterization of Thin Layer SnO 2 /Glass by Neutrons Reflectometry(Scientific.net, 2009) Khelladi, Mohamed Fadel; Izerrouken, M.; Kermadi, Salim; Tala-Ighil, RazikaThe thermal annealing behavior of the SnO2 thin films elaborated by sol-gel method has been studied by the neutrons reflectivity technique. From the fit of the experimental data using Parratt32 software program developed at HMI, Berlin, scattering length density, thickness and roughness are extracted. The obtained results show that the film thickness increases with the increasing annealing temperature, and the roughness is higher at 500 °C. Whereas, approximately, the same scattering length density is obtained after each annealing temperatureItem Preparation and characteristic of low resistive zinc oxide thin films using chemical spray technique for solar cells application(2008) Sali, S.; Boumaour, Messaoud; Tala-Ighil, RazikaIn this paper, we present results concerning undoped and indium-doped zinc oxide (ZnO: In) thin films were grown on glass and Si substrates using the chemical spray technique. The effects of thickness (e), as well as the substrate temperature (Ts), were studied. It was revealed by X-Ray diffraction that the preferred orientation of polycrystals is along C-axis, with hexagonal wurtzite structure. Two important facts were calculated from RBS measurements: the dopant concentration throughout the film and the thickness of the films, it was found that the thickness increase with time of deposition. Under optimum deposition conditions a low resistivity and a high optical transmittance of the order of 2.8 × 10−4 Ω cm and 85 %, respectively, were obtained.Item Effect of H2O Content on Structure and Optical Properties of TiO2 Thin Films Derived by Sol-Gel Dip-Coating Process at Low Temperature(2008) Kermadi, Salim; Agoudjil, N.; Sali, S.; Tala-Ighil, RazikaPure TiO2 thin films were prepared on the glass substrates by sol–gel dip coating technique with titanium (IV) isopropoxide including simultaneously acetylacetone and acetic acid as stabilizing reagents. The effect of the amount of water in the sol on structural and optical properties of TiO2 thin films was investigated. The structural and optical properties of post- sintered films for 1 hour at 500°C in air were investigated By X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectroscopy and ellipsometry. The results showed a simultaneous appearance of the rutile and the anatase phases with different rutile / anatase proportions for all samples. The increase of the water content leads to the decrease of rutile / anatase proportion. The crystalline size varies from 7.94 to 24.84 nm for the anatase phase and from 17.70 to 22.31 nm for the rutile phase. The optical measurements showed that the structure was strongly influenced by the water / alcoxides molar ratios. In comparison with the bulk material, the TiO2 thin films prepared by this way exhibit low refractive index in the range of 2.15 and high band gap energy narrowing from 3.88 to 3.95 eV for direct allowed transition and from 3.09 to 3.39 eV for indirect allowed transition according to the cristallinity degree and the rutile /anatase weight fraction.Item Measurement of Square Resistance In Situ of SnO2: F Thin Film With Annealing at High Temperature Under Air(ICTP, 2008) Tahi, Hakim; Boumaour, Messaoud; Tala-Ighil, Razika; Belkaid, M. S.Thin films of fluorine doped tin oxide (SnO2: F), deposited by spray pyrolysis on silicon substrate, were characterized by the method of four points probe in situ during annealing at high temperature under air. The evolution of square resistance (in situ) with the annealing temperature was interpreted in terms of competition between electronic conduction and ionic conduction. A square resistance of 136�/□ is measured before annealing and after annealing at 900°C, the square resistance increases appreciably to reach 40k�/□. This increase is explained by the absorption of oxygen at the films surface and an increase in SiO2 thickness at interface SnO2/SiItem Numerical Simulation of Silicon Based Solar Cells with a Degenerated SnO2:F Window Layer(Cambridge Core, 2007) Tala-Ighil, Razika; Boumaour, MessaoudThe paper presents a numerical simulation of the behaviour of SnO{2}:F/Si(N+)/Si(P) solar cells. The simulation addresses in particular the question of the role of the window layer SnO{2}:F for the device performance. As beginning step, the transparent conductive oxide of SnO{2}:F must be modelled in order to introduce its parameters in simulation codes. Two approaches were employed: one empirical by collecting the experimental data of spray deposited SnO{2}:F while the second one is theoretical by using models of highly degenerate wide band gap semiconductors. The second step consists in injecting the deduced parameters of fluorine doped tin oxide in simulation codes. We use two well-known photovoltaic simulation codes as PC1D and SCAPS 2.5. A comparative study of the results of structures SnO{2}:F/Si(N+)/Si(P) and Si(N+)/Si(P) have been done with a confirmation in enhancing the conversion efficiency by SnO{2}:F window layer addition.Item The Effect of CO Reducing Atmosphere on the Structural and Optical properties of SnO2: F films Deposited on a Si( N+)/Si(P) solar cell(2006) Tala-Ighil, Razika; Boumaour, Messaoud; Maallemi, Abderrezak; Melhani, KheiraItem Effect of Er doping on the microstructural, optical, and photocatalytic activity of TiO2 thin films(Iop science, 2018) Abdelali, Aouina; Bensouici, F.; Bououdina, M.; Tala-Ighil, Razikaanostructured Er³⁺ doped TiO2 thin films are deposited onto glass substrate via sol-gel dip-coating followed by calcination at 450 °C for 1 h. X-ray diffraction analysis confirms that the films crystallized within single tetragonal anatase phase. Atomic force microscopy observations reveal that the surface of pure TiO2 is characterized by ninepins then becomes smooth and porous for Er-doped TiO2 thin films, while the roughness decreases drastically from 17.2 to 2.6 nm with increasing Er³⁺ percentage. Wettability tests show a super-hydrophilicity character of 0.2 and 0.3%Er doped TiO2 thin films. UV–vis analysis reveals high transmittance above 85% with the presence of interferences indicating the high quality of films. Meanwhile, the energy band gap decreases slightly from 3.31 eV for un-doped to 3.26 eV for 0.4%Er, with a red-shift in the optical absorption edge. High photocatalytic activity using methylene blue indicator has been achieved for 0.2% Er³⁺–TiO2 thin film, reaching 95% for 3 h.Item Adsorption and dissociation of H2S on the anatase TiO2 (100) surface: DFT + U study(Iop science, 2018) Nehaoua, N.; Belkada, R.; Tala-Ighil, RazikaThis paper discusses the adsorption and dissociation of the hydrogen sulfide (H2S) molecule on the titanium dioxide surface. They were studied by density function theory (DFT). The GGA + U approach was used to analyze the adsorption behavior of the H2S molecule on the TiO2 anatase (100) surface. The results presented include adsorption energies, structural and electronic properties, charge transfer and work function. Different adsorption configurations are considered with coordination of H2S at the surface (Ti5c, (Ti5c)2, O2c and O3c sites). The calculated adsorption energies are -0.31, -0.28, -1.14 and -5.66 eV. The most favorable adsorption sites lead to the dissociation of H2S into HS and H, where the S atom of HS binds to Ti5c or O2c atoms, leaving a dissociated H atom bonded to another O2c site. Analysis of Bader's charges reveals a significant charge transfer between the molecule and the surface of the TiO2 anatase. The adsorption process reduces the work function and bandgap of the system, which improves the photocatalytic properties of TiO2Item Materials Research Express Paper Effects of thermal treatment and layers' number on SnO2 thin films properties prepared by sol-gel technique(Iop science, 2019) Haouanoh, D.; Tala-Ighil, Razika; Toubane, MahdiaTin oxide layers are very important in photovoltaic applications. This paper presents an in-depth study of the SnO2 thin films deposited by the gel dip coating technique on glass substrates. The heat treatment and the number of layers effect on structural, morphological, optical and electrical properties were studied. Differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) showed that SnO2 crystallized at 402.5 °C. The diffraction spectra x-rays revealed that a formation of tetragonal cassiterite structure with a preferred growth orientation according to (101) plane. Exceptional film prepared at 200 °C preheated temperature is according to the (110) plane growth orientation. The size of the crystallites is strongly influenced by the preheated temperature, annealing temperature and a number of layers. The AFM images show homogeneous surfaces for all samples except the film prepared at a preheated temperature of 200 °C. However, it becomes smoother by increasing the number of layers. UV-Visible spectroscopy has shown that greater transparency is found in the infrared and visible domains (75%–96%). For all films, the optical band gap energy varies randomly with the preheated temperature; conversely, it increases from 3.83 eV to 3.88 eV for three-layer and six-layer films respectively. The energy gap decreases for samples with more than 6 layers. The minimum resistivity values are 8.1 10–1 Ω cm determined by the four probe method for the sample preheated to 400 °C without annealing temperatureItem A first-principles computational and experimental investigation on schiff base cobalt complex towards designing solar cells(Elsevier, 2019) Choukab, Rihab; Aguira, Chadlia; Haouanohc, Djedjiga; Bergaouia, Manel; Tala-Ighil, RazikaA synthesized cobalt complex (Co-NG) based on a Schiff base, derived from ninhydrin and glycine ligand, with cobalt Co (II) metal is presented. A combined theoretical and experimental study is performed. The Co-NG crystalline structure is obtained from XRD spectra, which reveals that the crystal belongs to the triclinic system. Furthermore, the FT-IR spectrum clearly shows that the complex behaves as tridentates monobasic ONO donor ligand. In addition, the optical observations in different solvents show a good absorption in visible especially in Dimethyl sulfoxide (DMSO) solvent with two maxima around 415 nm and 604 nm. Moreover, the Density Functional Theory (DFT) calculations reveal that the Co-NG complex has an energy gap equal to 2.85 eV, where the LUMO energy of the dye is above the TiO2 conduction band and the HOMO energy is below the electrochemical potential of redox couple I−/I3− in the electrolyte. Finally, some photovoltaic parameters including the electron injection () and the redox process rate (), which are equal to – 0.29 eV and - 1.82 eV, respectively, are estimated. These interesting properties make the Co-NG complex a potential sensitizer for dye sensitized solar cell devices