Publications Internationales

Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13

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Subject: search.filters.subject.Structural properties

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    Impact of substrate on the formation mechanism of electrodeposited Co–Ni thin films: a comprehensive study of structural, morphological, and magnetic properties
    (Springer, 2024) Boulegane, Ala; Guittoum, Abderrahim; Hadj Larbi, Abderrahim; Laggoun, Ali; Boudissa, Mokhtar
    In this work, we investigated the effect of substrate on the structural, morphological, and magnetic properties of electrodeposited CoNi thin films from a chloride bath. Three samples of CoNi films were deposited at room temperature onto different substrates: FTO, ITO, and Cu. Electrochemical studies were performed using cyclic voltammetry experiments. Energy-dispersive X-ray spectroscopy (EDX) showed that all the samples had a cobalt content of more than 80%. X-ray diffraction (XRD) spectra revealed that the films deposited on Cu had a face-centered cubic (FCC) phase, while those deposited on ITO and FTO had a mixture of hexagonal close-packed (HCP) and FCC phases. The lattice parameter (a) and crystallite size (D) were strongly dependent on the substrate. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe the morphology of the films. All the samples had a granular morphology with spherical grains, but the roughness and surface distribution varied with the substrate. The magnetic properties of the films, such as coercivity (Hc) and squareness (S), were investigated using a vibrating sample magnetometer (VSM). The results showed that Hc and S were both affected by the substrate and the film composition. Overall, our results showed that the substrate had a significant effect on the structural, morphological, and magnetic properties of electrodeposited CoNi thin films. These findings could be used to design and optimize CoNi thin films for specific applications.
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    Structural, morphological, and magnetic properties of electrodeposited coNi thin films on the FTO substrate
    (Springer, 2022) Boulegane, Ala; Guittoum, Abderrahim; Laggoun, Ali; Boudissa, Mokhtar; Hemmous, Messaoud
    CoNi films were elaborated by electrodeposition onto FTO substrates using a chloride bath with a metallic ion molar ratio [Co2+]/[Ni2+] equals 1/1. Three samples were elaborated for different potentials ranging from −1.6 to −1.5 V. The structure and the morphology of CoNi films were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The chemical compositions are obtained using energy dispersive X-ray (EDX) and the magnetic properties were studied using a vibrating sample magnetometer (VSM). From X-ray diffraction, we have shown the presence of the FCC phase of CoNi binary alloy with a well-pronounced texture along the < 111 > , < 200 > , and < 220 > planes for all samples. We have found that the applied potential has an influence on crystallite sizes. Besides, a moderate change in the lattice parameter has been observed with increasing applied potential. The AFM images show that the applied potential changes the morphology and the surface roughness of CoNi films. In addition, the SEM images confirm the granular morphology of CoNi deposits and show a good relationship between voltage and grain size. The EDX spectrums confirm the deposition of the cobalt and the nickel on the FTO substrate and show the precedence deposition of Co compared with Ni. The extracted coercive field Hc and squareness from the hysteresis loops explained the good correlation between the magnetic and structural properties of CoNi thin films
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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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    Optical, structural and photocatalysis properties of Cu-doped TiO2 thin films
    (Elsevier, 2017) Bensouici, F.; Bououdina, M.; Dakhel, A.A.; Tala-Ighil, Razika; Tounane, M.; Iratni, A.; Souier, T.; Liu, S.; Cai, W.
    Pure and Cu+2 doped TiO2 thin films have been successfully deposited onto glass substrate by sol–gel dip-coating. The films were annealed at 450 °C for 1 h and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), atomic force microscopy (AFM), UV–vis spectrophotometer and photocatalytic degradation of methylene blue. XRD confirmed the presence of two phases at higher Cu concentration; TiO2 anatase and CuO. AFM analysis showed that the surface roughness increases within increasing Cu content as well as the presence of large aggregates at higher Cu content. SEM observations confirmed the granular structure of the films, and EDX analysis revealed a low solubility limit (effective doping) of Cu into TiO2 lattice. It was found that the optical band gap energy decreases with increasing Cu content. At constant irradiation time, the photo-degradation of methylene blue rate decreased with increasing concentration of Cu+2