Browsing by Author "Sali, S."

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    Contact Resistance Determination For Multi-crystalline Silicon Solar Cells By Using Transmission Line Method (TLM)
    (2008) Tala-Ighil, Razika; Sali, S.; Oussalah, Slimane; Boumaour, Messaoud
    he main objective in solar cells realization consists in increasing their performances. The mechanisms of this increase obey specific phenomena of physics. There is necessarily a contact resistance value behind each value of conversion efficiency. The question is how to quantify the contact resistance and what is its behaviour with different temperature profiles and consequently with the conversion efficiency. This work responds to all of these questions. We have taken square multicrystalline silicon wafers of 10 cm sides. These wafers have followed the traditional process steps i.e.: chemistry, diffusion, silicon nitride PECVD deposition and metallization of the front grid with TLM (Transmission Line Method) mask. The TLM measures are obtained using a test bench which includes a four-point prober and an analyzer. The contact resistance is deduced by the plot of the resistance versus the TLM line distance. It represents the R(D2), R(D3), R(D23), R(D4) and R(D34) where D2, D3, D23, D4 and D34 are the TLM distances. The TLM resistance is the half of the intersection of the slope R(D) with the y-axis. A profile of the evolution of the contact resistance versus the screen printing temperature annealing from 650°C to 800°C for the multi-crystalline silicon solar cells has been obtained.
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    Effect of back contact material on CZTS solar cells simulated with AMPS
    (2015) Tala-Ighil, Razika; Toubane, Mahdia; Bensouici, F.; Slimani, Amel; Haouanoh, Djedjiga; Iratni, A.; Sali, S.
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    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, Razika
    Pure 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.
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    Effet du recuit de la métallisation par sérigraphie sur les propriétés optiques des couches minces de ZnO déposées par spray
    (2009) Belkhalfa, H.; Tala-Ighil, Razika; Sali, S.; Kermadi, S.; Sili, S.; Boumaour, M.; Tayour, F.; Ait Amar, F.; Si Ahmed, Y.
    L’oxyde de zinc est parmi les oxydes transparents et conducteurs les plus prometteurs dans le domaine du photovoltaïque. En effet, il joue le rôle de fenêtre optique permettant de capter plus de photons. Le présent travail consiste à étudier et comprendre le comportement du ZnO déposé par spray pyrolyse, avec le recuit de frittage à hautes températures de la métallisation par sérigraphie. La métallisation par sérigraphie est la technique de fabrication par excellence de cellules solaires à l’échelle industrielle. On se focalise surtout sur les propriétés optiques à partir des spectres de réflexion et de transmission par l’emploi de la méthode de Mueller. Après analyse des résultats, on remarque que l’énergie de gap du ZnO décale vers les basses énergies avec le recuit. Elle démarre de 3,49 eV pour l’échantillon sans recuit à 3,26 eV pour l’échantillon recuit à 900 °C
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    Electrical and morphological study of screen printed silicon solar cells contacts
    (2012) Tala-Ighil, Razika; Chelli, F.; Sali, S.; Oussalah, S.; Boumaour, M.; Tayour, F.; Si-Ahmed, Y.
    The screen printed contact quality influences directly the mono-crystalline silicon solar cells efficiency. This is the aim of this study. A batch of mono-crystalline silicon wafers have undergone all the technological processes such as chemical cleaning, phosphorus diffusion and finally screen printing metallization. According to the used silver paste technical data, the firing temperature should not be greater than 750°C. This is why for this last step, a temperature swept from 650°C to 750°C has been carried out. The principal purpose of this work is to evaluate the Ag/N+ front contact quality by identifying the specific contact resistance, the resistivity and the morphology of each temperature profile. Transmission line method (TLM) is used as the technique for photovoltaic electrical characterization. It has been found that the best annealing temperature profile is750°C which corresponds to the lowest specific contact resistivity value of 1.65 mcm2. Morphological study shows low contact porosity at 750°C which reflects its good quality
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    Mesure statistique de la résistance de contact d’une grille sérigraphiée pour cellules solaires au silicium multicristallin
    (2010) Chelli, F.; Tala-Ighil, Razika; Sali, S.; Si-Ahmed, Y.; Oussalah, S.; Tayour, F.; Boumaour, M.
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    Neutron characterization of thin layer SnO2/Glass by neutrons reflectometry
    (2009) Khelladi, M. F.; Izerrouken, M.; Kermadi, Salim; Tala-Ighil, Razika; Sali, S.; Boumaour, Messaoud
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    Photoluminescence and structure of ZnO films deposited on i substrates by chemical spray deposition
    (2009) Sali, S.; Tala-Ighil, Razika; Kermadi, Salim; Kechouane, M.; Boumaour, Messaoud
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    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, Razika
    In 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.
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    Sol-Gel synthesis of SiO2-TiO2 film as antireflection coating on silicon for photovoltaic application
    (2009) Kermadi, Salim; Agoudjil, N.; Sali, S.; Tala-Ighil, Razika; Boumaour, Messaoud