Browsing by Author "Ammar Boukhari"

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    Experimental and theoretical studies on structural, morphological, electronic, optical and magnetic properties of Zn1-xCuxO thin films
    (2021) Elhadj Benrezgua; Bahri Deghfel; Abdelhafid Mahroug; Muhamad Kamil Yaakob; Ammar Boukhari; Rabie Amari; Soorathep Kheawhom; Ahmad Azmin Mohamad
    Pure and copper-doped zinc oxide thin films at different contents x (Zn1-xCuxO; 0≤x ≤ 0.125) were synthesized by sol–gel spin coating process and investigated using various techniques. All samples exhibited a polycrystalline with wurtzite hexagonal phase, which wasn't altered and getting relaxed by Cu-doping. The grain size increased and changed its growth mode from c-axis growth to lateral one and the surface morphology was strongly influenced with increasing level of Cu doping. As x increased, the transparency of films was generally increased in the visible region and the band gap energy (Eg) presented a slight shrinking, indicating that the prepared films are suitable for use in opto-electronic applications. Ferromagnetic phase was adopted within density functional theory corrected by Hubbard method (DFT+LDA+U) to investigate the structural, electronic, magnetic and optical properties of pure and CZO structure. The closest Cu impurities gave the more stable configuration. Cu3d states were distributed around Fermi level inducing a major contribution to the magnetic moment. A mix of ionic and covalent bonding was remarked. DFT + LDA + U enhanced significantly the calculated Eg, which presented a narrowing with x. The imaginary part of the dielectric functions presented three main peaks and their static constants were slightly influenced by Cu doping.
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    Thickness effect on the properties of Mn-doped ZnO thin films synthesis by sol-gel and comparison to first-principles calculations
    (Université de M'sila, 2022) Ammar Boukhari
    The current study investigates the effect of thickness on the structural, morphological, electronic, and optical properties of pure zinc oxide (ZnO) and 7% Mn-doped ZnO thin films, deposited by sol–gel spin coating method. All films exhibited a hexagonal wurtzite structure with a high preferential c-axis orientation. The surface morphology showed a good uniformity with cracks and wrinkles. The transmittance decreased with thickness. The bandgap energy was inversely varying with coating number. Photoluminescence spectra showed ultraviolet with strong and weak blue and weak green emission peaks. Density functional theory and Hubbard (DFT + U) method was then applied to study the structural, electronic, and optical properties of pure and 6.25% Mn-doped ZnO materials. A decrease in bandgap energy from pure to 6.25% Mn-doped ZnO material was shown using the DFT + U method. It also found that the Mn3d states were distributed far from Fermi level with a coexistence of both ionic and covalent nature bonds. A slight shift toward the lower energy was noticed for optical properties by Mn doping. The theoretical findings showed a similar behavior to those obtained by experiment.