Metin Bedir

Effect of sample producing conditions on the thermoluminescence properties of ZnS thin films developed by spray pyrolysis method

Abstract In this work, the effect of thin film production conditions (substrate temperature and ratio of starting material) was studied on the intensity of thermoluminescence (TL) signal and TL emission spectrum of ZnS samples that were grown by spray pyrolysis method. It was observed that the intensity of TL signal increases with increasing the substrate temperature ( T s ) and reaches a maximum point at the substrate temperature of 500°C with a high ratio of ZnCl 2 salt solutions. Secondly, it was observed that the energy level of trap present in ZnS samples is not single-level but instead has a distribution of energy levels. The type of the trap distribution is probably an exponential distribution. However, the distribution of energy levels approaches to single energy level with increasing substrate temperature.

Characterization of Undoped and Cu-Doped ZnO Thin Films Deposited on Glass Substrates by Spray Pyrolysis

Undoped and copper doped zinc oxide (ZnO) thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt (CuCl2) in the spray solution of ZnO. Variation of structural, electrical, optical and thermoluminescence (TL) properties with doping concentrations is investigated in detail.

Structural and Optical Properties of Nanocrystal In2O3 Films by Thermal Oxidation of In2S3 Films

In2S3 nanocrystalline films are prepared on glass substrates by the spray pyrolysis technique using indium chloride and thiourea as precursors. The deposition is carried out at 350°C on glass substrates. The films are then annealed for two hour at 200, 400, 600, and 800°C in O2 flow. This process allows the transformation of nanocrystal In2O3 films from In2S3 films and the reaction completes at 600°C. These results indicate that the In2O3 film prepared by this simple thermal oxidation method is a promising candidate for electro-optical and photovoltaic devices.

A study on electrodeposited Ni x Fe1−x alloy films

NixFe1−x (0.22 ≤x ≤ 0.62) alloy films were grown by electrodeposition technique. A shift in diffraction peaks of NiFe and Ni3Fe was detected with increasing Ni content. The highest positive magnetoresistance ratio was detected as 5% in Ni0.51Fe0.49. Positive and negative anisotropic magnetoresistance were observed in longitudinal and transverse geometries respectively. The highest anisotropic magnetoresistance ratio of 9.8% was also detected in Ni0.51Fe0.49. The angular variation of magnetoresistance was studied. Magnetisation loop curves show that NiFe alloy films have a linear decreasing anisotropy constant with increasing Ni deposit content and show a decreasing behavior of coercivity which indicates soft magnetic property with increasing Ni deposit content

Temperature and Thickness Effects on Electrical Properties of InP Films Deposited by Spray Pyrolysis

InP film samples are prepared by spray pyrolysis technique using aqueous solutions of InCl3 and Na2HPO4, which are atomized with compressed air as carrier gas onto glass substrates at 500° C with different thicknesses of the films. The structural properties of the samples are determined by x-ray diffraction (XRD). It is found that the crystal structure of the InP films is polycrystalline hexagonal. The orientations of all the obtained films are along the c-axis perpendicular to the substrate. The electrical measurements of the samples are obtained by dc four-probe technique on rectangular-shape samples. The effects of temperature on the electrical properties of the InP films are studied in detail.

The Analysis of Main Dosimetric Glow Peaks in CaF2:Tm (TLD-300)

The thermoluminescence properties of CaF2:Tm (TLD-300) are examined in detail after β-irradiation at room temperature. The glow curve of the sample shows two main dosimetric glow peaks: P3 (at ~150°C) and P5 (at ~250°C). The additive dose, variable heating rate, computer glow curve deconvolution, peak shape and three points methods are used to evaluate the trapping parameters, namely the order of kinetics (b), activation energy (E) and frequency factor (s) associated with the dosimetric thermoluminescent glow peaks (P3 and P5) of CaF2:Tm (TLD-300) after different dose levels with β-irradiation.

Studies on structural and electrical properties of MnO films prepared by the spray pyrolysis method

MnO film samples of various thicknesses were prepared by the spray pyrolysis technique via the atomization of MnCl2 aqueous solutions onto glass substrates held at 350 °C using compressed air as a carrier gas. The crystal structure of the MnO films that was determined by x-ray diffraction was found to be polycrystalline. The crystalline structure of all the film samples showed a preferred orientation along the c-axis perpendicular to the substrate. The electrical parameters of the samples were obtained by applying the dc four-probe technique to rectangular-shaped samples. The effect of temperature on the electrical properties of MnO films is described here.

Effect of Water Concentration on the Characterization of Sprayed Cd0.5Zn0.5S Films

Cd0.5Zn0.5S film samples are prepared by a spray pyrolysis technique using aqueous solutions of CdCl2, ZnCl2, SC(NH2)2 and deionized water, which are atomized using compressed air as the carrier gas onto glass substrates with different water (H2O) concentrations. H2O is used as the activator. The prepared films are characterized by means of XRD and UV-VIS spectroscopy. Experimental results reveal that the structures and properties of the films are greatly affected by the H2O content. Water in a certain range of concentrations promotes the formation of the Cd0.5Zn0.5S films and improves the properties of the films.

Effect of the grain size on the structural and optical properties of the sprayed Cd x Zn 1-x S films

Cd_xZn_1-xS films were obtained with incorporation of Cd element into ZnS at different concentrations (0≤x≤1) by spray pyrolysis technique using aqueous solutions of CdCl₂, ZnCl₂ and (CS(NH)₂)₂, which were atomized with compressed air as carrier gas. The CdxZn1-xS films were obtained on glass substrates at substrate temperatures of 400°C. Effects of the grain size of the films on structural and optical properties of sprayed cadmium zinc sulfide (CdZnS) films were investigated. It was seen that the crystallinity level of the films increased. with increasing x composition and grain size.

Investigation of Structural and Optical Properties of InP Thin Films Developed by Using Spraying Method

Structural and optical properties of InP films developed with the solutions prepared with InCl3 and Cl2HPO4 salts having different rates by using spraying method have been investigated using the data obtained from UV spectrometer and XRD (x‐ray difractometer). Band gap energy values of all samples obtained by using UV spectrometer are found in 1.60–1.85 eV range. It was observed that basic piks of all samples are in (200) plane and have a fcc structure in the XRD analysis. In addition, grain size of the samples increases with the rate of indium included in samples and it is seen that the crystallization in surface structure tends to become more homogenity.