Research Outputs

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Browsing Research Outputs by Department "Department of Physics"

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    Europium doping-induced stability and quantum confinement effect in ZnO quantum well wires QWW: Electronic structure calculation and material structural investigation in terms of band-gap shift
    (2016) Yahşi, Uğur; Yumak, Ayşe; Petkova,Petya; Boubaker,Karemt Ben Mahmoud; TR101223; TR1518; Department of Physics
    ZnO quantum well wires QWW have been grown on glass substrates by an inexpensive, simplified and enhanced spray pyrolysis technique, at 460°C and using Zn(CH3COO)2·2H2O as main precursor. Consecutively, the as-grown wires have been gradually doped by Europium within hexa-hydrated chlorinated Europium EuCl3·6H2O (ACROS, 99.0% purity) with different europium-doping levels (0, 0.5 and 1.0 at%). The effects of Eu-doping on the structural and optical properties of the QWW were investigated. Results reflect that accuracy of control can be achieved on functional performance by adjusting doping extent. Two-dimensional self-consistent calculations of the electronic structure within the Brillouin zone, along with Lattice Compatibility Theory analyses results show excellent agreement with the experimental results. © 2015 Elsevier B.V.
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    Physical investigations on perovskite LaMnO3-δ sprayed thin films for spintronic applications
    (2016) Yumak, Ayşe; Boukhachem,Abdelwaheb; Ziouche, Aicha; Amor, M.Ben; Kamoun,Olfa; Zergoug,Mourad; Meherzi,H. Maghraoui; Boubaker,Karemt Ben Mahmoud; Amlouk,Mosbah; Department of Physics
    Oxygen deficient LaMnO3 thin films were successfully grown on glass substrate by spray pyrolysis at 460 °C. XRD studies show oxygen vacancies corresponding to the orthorhombic La4Mn4O11 with (040) preferential orientation. Optical properties were investigated through optical band gap and Urbach energy. The dispersion of the refractive index was discussed in terms of both Cauchy and Wemple & Di-domenico models. Raman spectroscopy shows the band positions corresponding to LaMnO3 with a shift related to oxygen deficiency. Electrical properties were quantified using impedance spectroscopy technique within frequency range of 5 Hz-13 MHz at various temperatures. Both the DC conductivity and relaxation frequency were thermally activated with activation energy around 0.9 eV. Also, AC conductivity was investigated through Jonscher law. Finally, magnetic measurements at room temperature using vibrating sample magnetometer (VSM) technique show ferromagnetic behavior of these ternary sprayed thin films. © 2015 Published by Elsevier Ltd.