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    The low resistive and transparent Al-doped SnO2 films: p-type conductivity, nanostructures and photoluminescence
    (ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 2014) Benouis, CE; Benhaliliba, M; Mouffak, Z.; Avila-Garcia, A.; Tiburcio-Silver, A.; Lopez, M. Ortega; Trujillo, R. Romano; Ocak, Y. S.
    In this work, we study the crystalline structure, surface morphology, transmittance, optical bandgap and n/p type inversion of tin oxide (SnO2). The Nanostructured films of Al-doped SnO2 were successfully produced onto ITO-coated glass substrates via the spray pyrolysis method at a deposition temperature of 300 degrees C. A (101) and (211)-oriented tetragonal crystal structure was confirmed by X-ray patterns; and grain sizes varied within the range 8 42 nm. The films were polycrystalline, showing a high transparency in the visible (VIS) and infrared (IR) spectra. The optical bandgap was estimated to be around 3.4 eV. The atomic force microscopy (AFM) analysis showed the nanostructures consisting of nanotips, nanopatches, nanopits and nanobubbles. The samples exhibited high conductivity that ranged from 0.55 to 10(4) (S/cm) at ambient and showed an inversion from n to p-type as well as a degenerate semiconductor characters with a bulk concentration reaching 1.7 x 10(19) cm (3). The photoluminescence measurements reveal the detection of violet, green and yellow emissions. (C) 2014 Elsevier B.V. All rights reserved.
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    Öğe
    The sprayed ZnO films: nanostructures and physical parameters
    (Iop Publishing Ltd, 2015) Benhaliliba, M.; Tiburcio-Silver, A.; Avila-Garcia, A.; Tavira, A.; Ocak, Y. S.; Aida, M. S.; Benouis, C. E.
    We synthesized the pure and indium-doped (IZO) ZnO films with a facile composition control spray pyrolysis route. The substrate temperature (T-s) and In-doping effects on the properties of as-grown films are investigated. The X-ray pattern confirms that the as-synthesized ZnO phase is grown along a (002) preferential plane. It is revealed that the crystalline structure is improved with a substrate temperature of 350 degrees C. Moreover, the morphology of as-grown films, analyzed by AFM, shows nanostructures that have grown along the c-axis. The (3 x 3 mu m(2)) area scanned AFM surface studies give the smooth film surface RMS < 40 nm. The UV-VIS-IR measurements reveal that the sprayed films are highly transparent in the visible and IR bands. The photoluminescence analysis shows that the strong blue and yellow luminescences of 2.11 and 2.81 eV are emitted from ZnO and IZO films with a slight shift in photon energy caused by In-doping. The band gap is a bit widened by In-doping, 3.21 eV ( ZnO) and 3.31 eV (IZO) and the resistivity is reduced from 385 to 8 Omega.m. An interesting result is the resistivity linear dependence on the substrate temperature of pure ZnO films.