Yazar "Aida, M. S." seçeneğine göre listele

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    Gadolinium doping effect on SnO2 thin films optical and electrical properties
    (Iop Publishing Ltd, 2019) Adjimi, A.; Aida, M. S.; Attaf, N.; Ocak, Y. S.
    Undoped SnO2 thin films, as well as Gd-doped SnO2 thin films, were deposited on glass substrate by spray pyrolysis technique. The effect of gadolinium concentration and substrate annealing on structural, optical and electrical properties of SnO2 films are investigated. The structural properties of these thin films were analyzed using x-ray diffraction (XRD). XRD analysis confirmed the polycrystalline tetragonal crystalline structure of the films with mainly (110) preferential growth plane. The crystallite size has been reduced from 35 nm to 15 nm with increasing Gd dopant concentration. The films optical transmittance spectra exhibit high transparency of about 76%-87% in visible region. The films optical gap is enlarged from 3.43 eV in the un-doped films to 3.71 eV when Gd doped. The films figure of merit revealed a maximum value of about 8.2 x 10(-3) (Omega/sq)(-1) at 550 nm wavelengths. The highest conducting and transparency are obtained in the film prepared with 3 wt% Gd doping ratio. Hence, we conclude that 3 wt% ratio is the optimal one required for Gd:SnO2 film production that may found optoelectronic applications, in particular, as window layer in solar cells.
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    Investigation of ZnO nanostructures: Effect of metal and spinning speed on the physical properties
    (Inderscience Publishers, 2013) Benhaliliba, Mostefa; Benouis, Chahinez E.; Aida, M. S.; Ocak, Yusuf Selim; Yakuphanoǧlu, Fahrettin
    In this current work, we report on the surface morphology of pure (ZnO) and metal doped (MZO, M = Cu, Fe and Cd) zinc oxide nanostructures grown by sol-gel spin coating route onto a glass substrate at room temperature and speed of 1,000 rpm. We also investigate the effect of spinning speed on the physical and surface properties of coated ZnO films. The doping ratios Cu/Zn, Fe/Zn, Cd/Zn were kept at 2% in the solution. Atomic force microscope (AFM) revealed that nano-grains change in shape and growth orientation as a result of metal content. Average of grains sizes were found to be 87, 122, 174 and 260 nm respectively for pure, Cu, Fe and Cd doped ZnO. Based on the histogram profile, the shape looks like Gaussian curve for the pure ZnO, and it changes considerably for the M-doped ZnO films. Parameters of surface are investigated such as distribution of heights, power spectrum density (Psd), Fourier transform (Ft) of the picture and surface roughness (Rms). Spinning speed influences the surface and physical properties of coated ZnO films. The optimum results, high transparency (?72%) and low resistivity (9 k?cm), have been obtained with an increase in speed.
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    Nanostructured device based on coated ZnO layer as a window in solar cell applications
    (Sciendo, 2018) Mokhtari, Hossein; Benhaliliba, Mostefa; Boukhachem, A.; Aida, M. S.; Ocak, Yusuf Selim
    This work highlights some physical properties related to the influence of aluminum, tin and copper incorporation on nanostructured zinc oxide (ZnO:M; M:Al, Sn and Cu) thin films prepared by ultrasonic spray pyrolysis technique (USP) on glass substrate at 350±5 °C. For the as-grown layers, M- to Zn-ratio was fixed at 1.5 %. The effects of metal doping on structural, morphological, optical and electrical properties were investigated. X-ray diffraction pattern revealed that the as-prepared thin films crystallized in hexagonal structure with (0 0 2) preferred orientation. The surface topography of the films was performed by atomic force microscopy. AFM images revealed inhibition of grain growth due to the doping elements incorporation into ZnO matrix, which induced the formation of ZnO nanoparticles. Optical measurements showed a high transparency around 90 % in visible range. Some optical parameters, such as optical band gap, Urbach energy, refractive index, extinction coeffi-cient and dielectric constant were studied in terms of doping element. Particularly, dispersion of refractive index was discussed in terms of both Cauchy and single oscillator model proposed by Wemple and DiDomenico. Cauchy parameters and single oscillator energy E 0 as well as dispersion energy E d were calculated. Finally, electrical properties were investigated by means of electrical conductivity and Hall effect measurements. The measurements confirmed n type conductivity of the prepared thin films and a good agreement between the resistivity values and the oxidation number of doping element. The main aim of this work was the selection of the best candidate for doping ZnO for optoelectronics applications. The comparative study of M doped ZnO (M:Al, Sn and Cu) was performed. High rectifying efficiency of the Al/n-ZnO/p-Si/Al device was achieved and non-ideal behavior was revealed with n > 4.
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    Preparation and characterization of nanostructures of in-doped ZnO films deposited by chemically spray pyrolysis: Effect of substrate temperatures
    (Academic Press Ltd- Elsevier Science Ltd, 2013) Benhaliliba, M.; Benouis, C. E.; Mouffak, Z.; Ocak, Y. S.; Tiburcio-Silver, A.; Aida, M. S.; Garcia, A. A.
    We deposited undoped (ZnO) and indium-doped ZnO (IZO) films onto glass substrate via ultrasonic spray pyrolysis technique. The variation in structural, surface morphology, electrical, optical and photoluminescent properties as a function of substrate temperature is investigated. X-rays pattern confirms that as-synthesized IZO phase is grown along a (002) preferential plane. Nanosized grains (<50 nm) are determined by X-ray analysis. Morphology of as-grown films shows broadened nanostructures which have grown along c-axis and nanostructures are found to be smooth (RMS similar to 60 nm). Study by spectrophotometer reveals that the asgrown films are highly transparent in the visible and IR spectra (T similar to 88%), and that the bandgap is slightly narrowed (3.17 eV). Electrical measurements confirm the enhancement of conductivity, rho<1 Omega cm, due to indium incorporation into the starting solution. An electron concentration of 10(17) cm(-3) and a mobility of 3 cm(2)/Vs are found for IZO films grown at 400 degrees C. The photoluminescence analysis demonstrates strong yellow (2.1 eV) and blue (2.8 eV) light and weak green (2.3 eV) emissions. (C) 2013 Elsevier Ltd. All rights reserved.
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    Spectroscopic ellipsometry, optical, structural and electrical investigation of sprayed pure and Sn-doped ZnO thin films
    (E D P Sciences, 2012) Mokhtari, H.; Benhaliliba, M.; Aida, M. S.; Attaf, N.; Ocak, Y.
    in this work, we report the transparent pure and Sn-doped zinc oxide (ZnO). The films were deposited onto microscope glass substrate which was heated at 350+/-5C degrees by ultrasonic spray pyrolysis (U S P) deposition technique. The concentrations of Sn were selected within the range of 0-3% by step of 0.5% and the time deposition is kept at 5 min. A (002)-oriented wurtzite crystal structure was confirmed by X-rays patterns; and grain size varied within the range 7.37-14.84nm, and cristanillity is calculated goes from14.4 to 45.9%. Based on UV-VIS-IR analysis, the results revealed the high transparency of the sprayed films which exceeds 90%. The band gap energy was of 3.26-3.30 eV. The film thickness was estimated by spectroscopy ellipsometry and the found values were of 165-270nm. The refractive index is in the range of 2.75. The obtained electrical parameters were around 10(18) cm(-3), 3.6 cm(2)/Vs, 1.6 Omega.cm; 5.8cm(3)/C. finally the Sn-doping has influenced the physical parameters of as-ground ZnO films
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    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.
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    Thermal sulfurization effect on sprayed CZTS thin filmsproperties and CZTS/CdS solar cells performances
    (Iop Publishing Ltd, 2018) Boutebakh, F. Z.; Batibay, D.; Aida, M. S.; Ocak, Y. S.; Attaf, N.
    Cu2ZnSnS4 (CZTS) thin films were successfully deposited by a simple and inexpensive technique such as ultrasonic spray pyrolysis. The effect of sulfurization temperature on CZTS films properties and on Mo/CZTS/CdS/ZnO/ZnO:Al solar cell performances were studied. The investigated sulfurization temperatures were ranged from 450 degrees C to 550 degrees C. X-ray-diffraction pattern and Raman scattering spectroscopy confirmed the formation of monophase kesterite CZTS, the best crystallinity was obtained in the sample sulfurized at 450 degrees C. Atomic forces microscopy images indicated that annealing temperature increase yields to rough films with large grain size. UV-visible optical transmittance spectroscopy reveals that films enjoy a strong absorption with an absorption coefficient as high as 104 cm(-3). Whereas, the optical band gap energy was found to decrease with sulfurization temperature. Hall effect measurements confirm the films p-type conductivity; the carriers concentration varies between 10(14) and 10(16) cm(-3) when the sulfurization temperature changes from 450 degrees C to 550 degrees C. The I-V characteristics of the realized Mo/CZTS/CdS/ZnO/ZnO:Al cells indicated that all the devices show a rectification behavior with an ideality factor ranged from 1.6 to 1.8. The current transport is dominated by the interfacial recombination process. The photovoltaic effect was observed, the best performance was achieved in the device prepared with CZTS sulfurized film at 450 degrees C, the recorded characteristics are: 0.43% efficiency, 9.8 mA cm(-2) short circuit current, 161 mV open circuit voltage and 28% fill factor. A comparison between the reported results obtained by different techniques reveals the superiority of the cells prepared with CZTS deposited by physical deposition technique such as thermal evaporation or sputtering.