Browsing by Author "Zaabat, M."
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Item Effect of copper doping on the photocatalytic activity of ZnO thin films prepared by solegel method(Elsevier, 2015) Saidani, T.; Zaabat, M.; Aida, M.S.; Boudine, B.In the present work, we prepared undoped and copper doped ZnO thin films by the sol egel dip coating method on glass substrates from zinc acetate dissolved in a solution of ethanol. The objective of our work is to study the effect of Cu doping with different concentrations on structural, morphological, optical properties and photocatalytic activity of ZnO thin films. For this purpose, we have used XRD to study the structural properties, and AFM to determine the morphology of the surface of the ZnO thin films. The optical properties and the photocatalytic degradation of the films were examined by UVevisibles spectrophotometer. The Tauc method was used to estimate the optical band gap. The XRD spectra indicated that the films have an hexagonal wurtzite structure, which gradually deteriorated with increasing Cu concentration. The results showed that the incorporation of Cu decreases the crystallite size. The AFM study showed that an increase of the concentration of Cu causes the decrease of the surface roughness, which passes from 20.2 for Un-doped ZnO to 12.16 nm for doped ZnO 5 wt% Cu. Optical measurements have shown that all the deposited films show good optical transmittance (77%e92%) in the visible region and increases the optical gap with increasing Cu concentration. The presence of copper from 1% to 5 wt% in the ZnO thin films is found to decelerate the photocatalytic process.Item Fabrication, structural and optical characterization of In doped ZnO thin films prepared by the colloidal method(Oum-El-Bouaghi University, 2014) Medjaldi, M.; Touil, O.; Zaabat, M.; Boudine, B.; Halimi, O.; Sebais, M.Regarding to the excellent conductivity and high transparency in the visible range, the zinc oxide (ZnO) films have been widely used as transparent electrodes in optoelectronic devices, ZnO is a direct wide band-gap (3.37 eV) semiconductor. The conductivity of ZnO will be largely enhanced by doping little In, but it still keeps high transparency. So, IZO film has been widely investigated and is considered to be a promising possible alternative to ITO films. This work consist to the fabrication and characterization of ZnO:In thin films. The sample preparation was carried out by the colloidal method. The pure and In doped ZnO thin films were deposited using a dip-coating technique on glass matrix. The optimal condition for samples fabrication has been investigated. The XRD and Raman characterizations show that the ZnO thin film crystallize with a wurtzite structure. The optical properties of ZnO thin films doped In reveal that doping changes the optical gap of ZnO.Item Morphological And Optical Properties Of Sol-gel Derived Ni Doped Zno Thin Film(Oum-El-Bouaghi University, 2014) Saidani, T.; Zaabat, M.; Benaboud, A.; Boudine, A.In this work, we are interested in thin films of zinc oxide doped with nickel (Ni), deposited on glass substrates and elaborated by the sol-gel dip coating technique. The effects of the doping concentration in the range of outlet (1%, 3% and 5at%) have been thoroughly studied. The morphological properties of ZnO-Ni films were studied by Atomic Force Microscopy (AFM). The optical properties of the ZnO:Ni thin films were examined by UV-visible spectroscopy and the Tauc method was used to estimate the optical band gap and hall effect for electrical characteristique. Atomic Force Microscopy has indicated that the surface of the ZnO:Ni thin films have uniform and dense ZnO grains. The optical transmittance of ZnO:Ni thin films increased from 86 to about 93% from pure ZnO films to ZnO film doped with 3 wt% Ni and then decreased for 5 wt% Ni, and the optical band gap from 3.297 eV to 3.23eV. The electrical characterization performed using the technique of hall effect, gave a maximum electrical conductivity of 9.3 10-3(Ω.Cm)-1 obtained for the film doped with 3%Ni.Item Numerical analysis of GaAs MESFETs OPFET(Oum-El-Bouaghi University, 2011) Hamma, I.; Saidi, Y.; Zaabat, M.; Azizi, C.A Tow dimensional numerical model of channel potential for GaAs MESFET (Metal semiconductor field effect transistor) doped uniformly .the model takes into acount the effects in channel region considering both the photoconductive effect and photovoltaic effect at the gate schottky . the 2-D potential distribution function in the active layer of the divice is solved numerically under dark and illumination condition.Item The Copper Indium Selenium (CuInSe2) thin films solar cells for Hybrid Photovoltaic Thermal Collectors (PVT)(Elsevier, 2015) Haloui, H.; Touafek, K.; Zaabat, M.; Ben cheikh el hocine, H.; Khelifa, A.Ternary chalcopyrite compounds which may act as an absorber in thin films solar cells are mainly CuGaSe2, the CuInS2, CuInSe2 and the CuAlSe2. Because of their large optical absorption coefficient, a thickness of 1.5-2 microns is sufficient to absorb the useful portion of the solar spectrum. The most promising appears to be the CuInSe2 material, a 18.8% efficiency is obtained by the solar cells based on this material. However, its low band gap (1,04ev) limits the open circuit voltage and thus the efficiency of the solar cell. In this work we present the application of this material in hybrid photovoltaic thermal collectors (PVT). For the determination of its electrical and thermal performance through the development of a heat balance that involves heat exchange between the different components of the collector. The results obtained show that we can have a thermal efficiency equal to (85.68%) and an electrical efficiency of the order of (19.22%) for our PVT collector based on CIS are better than the values obtained by PVT collector based on monocristallin silicon.Item Two-dimensional spin-FET transistor(Springer, 2015) Boudine, A.; Kalla, L.; Benhizia, K.; Zaabat, M.; Benaboud, A.