Browsing by Author "Ozkartal, A."

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Characterization of the Ito/P-si Contacts Produced by Thermal Evaporation
(Elsevier Ltd, 2019) Ozkartal, A.
Indium-tin-oxide (ITO)/p-Si heterojunctions were produced by thermal evaporation using a vacuum coating unit. Cleaning process for the p-Si (1 0 0) crystal was carried out according to the conventional procedure. Prior to ITO evaporation, ohmic contact was made on the back side of the p-Si using Al (99.999%) metal. Optical transmission measurements of the ITO film was performed using a UV–Vis spectrophotometer. The fact that the ITO film shows a sharp absorbtion in a certain photon energy range points out it has a semiconductor property. So, optical band-gap of the ITO film was determined as 3.85 eV. The structural properties of the films were examined by x-ray diffraction spectroscopy (XRD). Current-voltage (I–V) measurements of the ITO/p-Si heterojuntions were performed under illumination and in dark to reveal photovoltaic and electrical properties of them, respectively. It is discovered from the I–V measurements that the ITO/p-Si heterojuctions have shown rectifier properties and exhibited low photovoltaic characteristic. © 2019 Elsevier Ltd
Measurements of K-Shell X-Ray Production Cross-Sections and Fluorescence Yields for Some Elements in the Atomic Number Range 28 ≤ Z ≤ 40
(Pergamon-elsevier Science Ltd, 2015) Yilmaz, R.; Tunc, H.; Ozkartal, A.
K shell X-ray production cross-sections (sigma(K alpha) and sigma(K beta)) have been measured for some elements in the atomic number range 28 <= Z <= 40. Measurements have been carried out at 16.896 keV excitation energy using secondary source. K X-rays emitted by samples have been counted by a Si(Li) detector with 160 eV resolution at 5.9 keV. The values of K-shell fluorescence yields (omega(K)) have been evaluated for the same elements. The results obtained for K X-ray production cross-sections and fluorescence yields have been compared with the theoretically calculated values and other available semiempirical values. (C) 2015 Elsevier Ltd. All rights reserved.
Relationship Between Photovoltaic and Diode Characteristic Parameters in the Sn/P-si Schottky Type Photovoltaics
(Pergamon-elsevier Science Ltd, 2016) Ozkartal, A.; Temirci, C.
In order to investigate relationship between photovoltaic and diode characteristic parameters, we fabricated four kinds of samples of Sn/p-Si Schottky type photovoltaics using surface treatment by anodic oxidation and chemical etching method. Diode and photovoltaic characteristics of the samples were determined from the current voltage measurements performed in dark and under illumination. Etching time of front surface of the p-Si substrate in HF solution used in the fabrication of Sn/p-Si Schottky type photovoltaics was found to be very influential on diode and photovoltaic parameters. Especially, an etching time of 30 s showed a positive effect both on diode and photovoltaic characteristic parameters. It was also observed that the characteristic parameters of the samples were affected negatively depending on the over-etching time. More importantly, a close relationship between photovoltaic parameters (fill factor, conversion efficiency) and diode parameters (ideality factor, series resistance) was observed. (C) 2016 Elsevier Ltd. All rights reserved.