Ultrasonic Spray Pyrolysis Deposited Copper Sulphide Thin Films for Solar Cell Applications

Polycrystalline copper sulphide (CuxS) thin films were grown by ultrasonic spray pyrolysis method using aqueous solutions of copper chloride and thiourea without any complexing agent at various substrate temperatures of 240, 280, and 320°C. The films were characterized for their structural, optical, and electrical properties by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), atomic force microscopy (AFM), contact angle (CA), optical absorption, and current-voltage (I-V) measurements. The XRD analysis showed that the films had single or mixed phase polycrystalline nature with a hexagonal covellite and cubic digenite structure. The crystalline phase of the films changed depending on the substrate temperature. The optical band gaps (Eg) of thin films were 2.07 eV (CuS), 2.50 eV (Cu1.765S), and 2.28 eV (Cu1.765S–Cu2S). AFM results indicated that the films had spherical nanosized particles well adhered to the substrate. Contact angle measurements showed that the thin films had hydrophobic nature. Hall effect measurements of all the deposited CuxS thin films demonstrated them to be of p-type conductivity, and the current-voltage (I-V) dark curves exhibited linear variation

The characterization of asphaltene behavior in some aromatic solvents by dynamic nuclear polarization technique

Dynamic nuclear polarization (DNP) studies of asphaltene/some hydrocarbons solutions were performed at 1.53. mT. The low field EPR spectrum of Asphaltene/Mesitylene sample was recorded. The DNP parameters such as enhancement factor, nuclear-electron coupling constant, saturation factor, leakage factor, the parameter for the relative importance of scalar and translational dipolar interaction and the total spin-lattice relaxation rate were determined. The effect of irradiation with neutrons from the Ra-Be source to the DNP parameters was investigated. Dissolved molecular oxygen effect on the enhancement factor for each sample was examined experimentally. We also make some interpretations depending on the results obtained for the interactions between nuclei of the solvent and electrons delocalized on the asphaltene. © 2010 Elsevier B.V.F-2009/44This work was partly supported by the Research Fund of the Uludag University Project number: F-2009/44. The authors would like to thank the Uludag University for financial support

Influence of oxide layer coating on giant magneto-impedance response in amorphous ribbons

Cobalt-rich amorphous ribbon (Fe5.85Co72.15Mo2B15Si5) 13 mm in length and 5 mm in width were coated with different oxide layers in order to improve their GMI response. The coating process was performed using a chemical Successive Ionic Layer Adsorption and Reaction (SILAR) technique at room temperature. Oxide layer coated ribbons were imaged by an Atomic Force Microscopy (AFM). The variations in oxide layers and their roughness were studied to elucidate the cause of the improvements in GMI ratios in amorphous ribbons

Investigation of giant magneto-impedance effect in inorganic nickel coated amorphous ribbons

Co-based amorphous ribbon Fe5.85Co70.15Mo4B15Si5 (Metglas 2705X) was coated by Nickel complexes in order to increase the giant magneto-impedance response. Influence of inorganic nickel complex coating on giant-magneto impedance (GMI) effect was investigated under varied applied dc fields (–8 kA/m < H dc < 8 kA/m) at a frequency range of 0.1–3.5 MHz. The results showed that the GMI effect and operating frequency on Co-based amorphous ribbons, which were coated by Ni film, have significantly improved as compared to the uncoated samples. The variations on permeability, transverse anisotpy and flux penetration in the coated ribbons cause this improvement in the GMI effect

The Influence of the magnetic susceptibility of coated amorphous ribbons on giant-magneto impedance

Different inorganic thin layers (based on Cobalt, Copper and Nickel complexes) were grown on the surface of Co-rich Fe5.85Co70.15Mo4B15Si5 (Metglas 2705X) amorphous ribbons by a chemical coating process to improve the giant magneto impedance (GMI) effect. Magnetic susceptibilities of the inorganic complexes were measured by the Gouy's method. Therefore, the influence of the magnetic susceptibility of thin layers, which are coated on the surfaces of the amorphous ribbons, on the GMI effect has been studied. Cobalt, copper and nickel complexes were found to be diamagnetic, paramagnetic and paramagnetic, respectively. The results showed that changes in the GMI effect are related to the magnetic susceptibility