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Öğe Electrical, structural and surface properties of fluorine doped tin oxide films(Elsevier Science Bv, 2010) Bilgin, V.; Akyuz, I.; Ketenci, E.; Kose, S.; Atay, F.Fluorine (F) incorporated polycrystalline SnO(2) films have been deposited onto glass substrates by ultrasonic spray pyrolysis technique. To possess information about the electrical properties of all films, their electrical conductivities were investigated depending on the temperature, and their activation and trap energies were analyzed. The crystalline structure, surface properties and elemental analysis of the SnO(2) films were examined to determine the effect of the F element. After all investigations, it was concluded that each fluorine incorporation rate has a different and important effect on the physical properties, and SnO(2):F (3 at%) films were found to be the most promising sample for energy conversion devices, especially as conducting electrode in solar cells with its improved structural and electrical properties as compared to others. (C) 2010 Elsevier B.V. All rights reserved.Öğe Optical characterization and determination of carrier density of ultrasonically sprayed CdS:Cu films(Elsevier, 2010) Kose, S.; Atay, F.; Bilgin, V.; Akyuz, I.; Ketenci, E.In this work, CdS and Cu doped CdS films (at the Cu percentages of 1, 3 and 5) have been deposited onto glass substrates at 350 + 5 degrees C by ultrasonic spray pyrolysis technique and their application potential for photovoltaic solar cells have been investigated. Optical properties and thicknesses of the films have been investigated by spectroscopic ellipsometry (SE). Ellipsometric angle psi was used as the source point for optical characterizations. The optical constants (n and k) and the thicknesses of the films have been fitted according to Cauchy model. Also, optical properties of the produced films have been analyzed by transmittance and reflectance spectra. Refractive index (n), extinction coefficient (k) and reflectance (R) spectra have been taken by spectroscopic ellipsometer, while transmittance spectra have been taken by UV/vis spectrophotometer. The optical method has been used to determine the band gap type and value of the films. Mott-Schottky (M-S) measurements have been made to determine the conductivity type and carrier concentration of the films. Samples showed n-type conductivity and carrier concentration of undoped CdS sample was found to be 1.19 x 10(19) cm(-3). Also, it was concluded that Cu doping has an acceptor effect in CdS samples. From the results of these investigations, the application potential of CdS: Cu films for photovoltaic solar cells as window layer was searched. (C) 2010 Elsevier B. V. All rights reserved.Öğe Optical characterization of SnO2:F films by spectroscopic ellipsometry(Elsevier Science Bv, 2010) Atay, F.; Bilgin, V.; Akyuz, I.; Ketenci, E.; Kose, S.Spectroscopic ellipsometry (SE), which is a non-destructive and a non-contact optical technique used in characterization of thin films, is widely used to determine thickness, microstructure and optical constants. In this work, the effect of F incorporation on optical properties of SnO2 films grown by ultrasonic spray pyrolysis technique (USP) is presented. The reflections, refractive indices and thicknesses of the films were investigated using room temperature spectroscopic ellipsometry. The optical constants and the thicknesses of the films were fitted according to Cauchy-Urbach model, and ellipsometric angle psi was used as source point for optical characterizations. Besides, transmittance spectra of the films were taken from UV spectrometer, and the optical method was used to determine the band gaps. Also, band tailing resulting from defects or impurities was investigated. From the results obtained from the optical analyses, the application potential of SnO2:F films for solar cell devices was searched. (C) 2010 Elsevier B.V. All rights reserved.Öğe Optical, structural and surface characterization of CdO:Mg films(Springer, 2011) Atay, F.; Akyuz, I.; Kose, S.; Ketenci, E.; Bilgin, V.In this work, we have tried to improve some physical properties of CdO films by Mg doping. Ultrasonic spray pyrolysis technique has been used to obtain the films. Thicknesses and refractive indices of the films have been determined by Spectroscopic ellipsometry technique using Cauchy-Urbach model for fitting. Transmission and reflectance spectra have been taken by UV Spectrophotometer, and band gap values have been determined by optical method. X-ray diffraction patterns have been used to study the structural properties. Texture coefficient, grain size and lattice constants have also been determined. AFM images have been taken to see the effect of Mg doping on surface topography and roughness of CdO films. Finally, it has been concluded that Mg doped CdO films (especially at 4%) have improved properties and are good candidates for photovoltaic applications.Öğe Optical, structural and surface characterization of ultrasonically sprayed CdO:F films(Elsevier Science Sa, 2011) Akyuz, I.; Kose, S.; Ketenci, E.; Bilgin, V.; Atay, F.In this work, we report the effect of F doping on some physical properties of CdO films. Ultrasonic spray pyrolysis technique has been used to obtain the films. Thicknesses, refractive indices and extinction coefficients of the films have been determined by spectroscopic ellipsometry technique using Cauchy-Urbach model for fitting. Transmission and reflectance spectra have been taken by UV spectrophotometer, and band gap values have been determined by optical method. X-ray diffraction patterns have been used to study the structural properties such as crystallinity level, texture coefficient, crystallite size and lattice constants. Atomic force microscope images have been taken to see the effect of F doping on surface topography and roughness of CdO films. Finally, it has been concluded that both of the F doped CdO films have improved properties and are promising materials for solar cell applications. (C) 2010 Elsevier B.V. All rights reserved.Öğe Some physical properties of In doped copper oxide films produced by ultrasonic spray pyrolysis(Elsevier, 2012) Kose, S.; Ketenci, E.; Bilgin, V.; Atay, F.; Akyuz, I.In this work, we have reported the effect of In doping on structural, optical and surface properties of copper oxide films obtained by a low-cost ultrasonic spray pyrolysis technique. Thicknesses, refractive indices and extinction coefficients of the films have been determined by Spectroscopic ellipsometry technique using Cauchy-Urbach model for fitting. A very good agreement was found between experimental and theoretical parameters with low MSE values. Transmission and reflectance spectra have been taken by UV Spectrophotometer, and band gap values have been determined by optical method. Structural properties of the films were investigated with X-ray diffraction patterns. In doping caused the films to growth through some certain directions. Atomic force microscope images have been taken to see the effect of In doping on surface topography and roughness of copper oxide films. Surface properties of undoped films have been improved by In doping. Lowest roughness values have been obtained for In doping at 1%. As a result, we have concluded that properties of copper oxide films which are commonly used in solar cells may have improved by In doping (especially In doped at 1%). (C) 2011 Elsevier B.V. All rights reserved.
