Yazar "Batibay, Derya" seçeneğine göre listele

Listeleniyor 1 - 7 / 7
  • [ X ]
    Öğe
    Co-sputtered Cu2ZnTi(S:Se)4 absorbers for thin film solar cells
    (Pergamon-Elsevier Science Ltd, 2020) Batibay, Derya; Ocak, Yusuf Selim; Genisel, Mustafa Fatih; Turan, Rasit
    Thin film solar cells are an exciting topic for low cost and high efficient solar cells. Owing to the high price of the indium metal in the fabrication of copper indium gallium diselenide (CIGS) solar cells, Cu2ZnSn(SSe)(4) thin films are used as a new material to reduce the cost and increase the efficiency. As an alternative absorber material for solar cell production, Cu2ZnTi(S:Se)(4) thin films were deposited by the co-sputtering method at various temperatures. During the deposition, Cu, ZnSe and Ti targets were used as metal sources. The Cu2ZnTi(S:Se)(4) thin films were annealed in H2S:Ar (1:9) atmosphere. The morphological, structural and optical properties of Cu2ZnTi(S:Se)(4) thin films was analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) Raman spectroscopy and UV-Vis-NIR spectrometer. It was seen that the thin films had good optical absorption till the infrared region and the band gap of the Cu2ZnTi(S:Se)(4) thin films were smaller than the conventional Cu2ZnSnS4 thin films. Furthermore, fabrication of a solar cell with 1.96% power conversion efficiency was reported using a Cu2ZnTi(S:Se)(4) thin film as a low cost absorber layer. (c) 2019 Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Diester Molecules for Organic-Based Electrical and Photoelectrical Devices
    (Springer, 2017) Topal, Giray; Tombak, Ahmet; Yigitalp, Esref; Batibay, Derya; Kilicoglu, Tahsin; Ocak, Yusuf Selim
    Diester derivatives of terephthalic acid molecules were synthesized according to the literature. Au/Diester derivatives/n-Si organic-inorganic (OI) heterojunction-type devices were fabricated, and the current-voltage (I-V) characteristics of the devices have been investigated at room temperature. I-V characteristics demonstrated that all diodes had excellent rectification properties. Primary diode parameters such as series resistance and barrier height were extracted by using semi-log I-V plots and Norde methods, and were compared. It was seen that there was a substantial agreement between results obtained from two methods. Calculated barrier height values were about the same with 0.02-eV differences that were attributed to the series resistance. Ideality factors, which show how the diode closes to ideal diodes, were also extracted from semi-log I-V plots. Thus, the modification of the Au/n-Si diode potential barrier was accomplished using diester derivatives as an interlayer. The I-V measurements were repeated to characterize the devices at 100 mW/cm(2) illumination intensity with the help of a solar simulator with an AM1.5G filter.
  • [ X ]
    Öğe
    n-Type conductivity of CuO thin films by metal doping
    (Elsevier Science Bv, 2019) Baturay, Silan; Tombak, Ahmet; Batibay, Derya; Ocak, Yusuf Selim
    Due to its unique electrical and optical properties, copper (II) oxide (CuO) potentially has a wide variety of applications. It is commonly known that CuO has p-type conductivity; however, we report observations of n-type conductivity in thin CuO films by metal doping for the first time. We achieved n-type electrical conductivity in CuO films with cobalt (Co) doping. Undoped and Co-doped CuO thin films were fabricated using a spin coating technique. Electrical parameters, specifically, the charge carrier concentration, sheet resistance, and conductivity type were investigated using a van der Pauw Hall measurement system. By 3 per cent of the cobalt doping conductivity type conversion was observed. The effects of metal doping on the width of the optical band gap were investigated using ultraviolet-visible spectrometry over the wavelength range of 300-1100 nm. The optical band gaps were found to be 1.43, 1.44, 1.44, 1.42 eV for un-doped, 2, 4 and 6% Co doped CuO thin films, respectively. The influence of different concentration ratio on the growth of CuO films was investigated using XRD. Microstrain (e), crystalline size (D) and dislocation density (delta) for all orientations were calculated from XRD analysis. (C) 2017 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    New chitin derivatives and their Schottky diodes: Synthesis and characterization
    (Sage Publications Ltd, 2019) Aksoy, Onder; Uzun, Ilhan; Topal, Giray; Celik, Omer; Ocak, Yusuf Selim; Batibay, Derya
    First, chitin was reacted with 4,5-dichlorophthalic acid and diphenic acid, and thus two new chitin derivatives (C45DA and CDA) were synthesized. Then, C45DA and CDA were characterized by various spectroscopies and techniques (FTIR, C-13 CP-MAS solid-state NMR, XRPD, SEM, and TGA/DTA). Besides, some electrical properties of C45DA were measured. After the characterization process, the Schottky diodes of C45DA and CDA were made. It was determined that these diodes showed photodiode characteristics at the same time. Later on, both electrical properties (phi(b), n, and R-s) and photoelectrical properties (I-illumination/I-Dark, I-SC and V-OC) of these diodes were determined.
  • [ X ]
    Öğe
    Optical and electrical properties of Ni-doped CdO thin films by ultrasonic spray pyrolysis
    (Springer, 2018) Ocak, Yusuf Selim; Batibay, Derya; Baturay, Silan
    Transparent conducting oxides like ZnO, CuO and CdO have applications in photovoltaic solar cells and optoelectronic devices. Recently, much thin film work has investigated the characteristic properties of CdO films. In this work, Ni-doped CdO films in different concentration ratio were successfully deposited on soda lime glass (SLG) substrate using ultrasonic spray pyrolysis (USP) technique. The influence of 1, 2, 3, and 5% Ni concentrations in the films on the structural (orientations, D, epsilon (str) ), morphological (roughness value), optical (transmittance, energy band gap) and electrical properties (electrical conductivity, carrier concentration, Hall mobility) of the deposited CdO thin films was studied, respectively. X-ray diffraction (XRD) studies indicated that the obtained CdO films had good crystallinity and cubic phases with (111), (200), (220), (311), and (222) orientations with increasing Ni concentrations in the thin film. The optical energy band gap, E (g) , was changed from 2.35 to 2.51 eV for wavelengths of 300-1100 nm for soda lime glass substrate. Atomic force microscopy showed the effect of the substrate temperature on the surface morphology and roughness of the obtained films. The roughness value of the obtained films decreased related to increasing of the Ni doped CdO films. Scanning electron microscopy showed nanostructure particles homogeneously distributed on the film surfaces. In addition, the electrical conductivity of the obtained films changed with various Ni concentrations like 0, 1, 2, 3 and 5 at.% in solution for increasing free carrier concentration.
  • [ X ]
    Öğe
    Schottky Diodes Based on the New Chitin Derivatives
    (Maik Nauka/Interperiodica/Springer, 2019) Aksoy, Onder; Uzun, Ilhan; Topal, Giray; Ocak, Yusuf Selim; Celik, Omer; Batibay, Derya
    New chitin derivatives were synthesized by the reactions of chitin with o-acetylsalicyloyl chloride and phthaloyl chloride and their structure was characterized by FTIR and C-13 CP-MAS solid-state NMR spectroscopy and X-ray powder diffraction technique. Also, the thermal and surface properties of the chitin derivatives were investigated by thermogravimetric analysis and a scanning electron microscope. In addition, some electrical properties of the polymers were determined using Hall effect technique. Then, the Schottky diodes were fabricated by the formation of interlayers of chitin derivatives between Au metal and n-Si semiconductor, and the electrical and photoelectrical properties of the diodes were determined.
  • [ X ]
    Öğe
    Synthesis, characterization, and Schottky diode applications of low-cost new chitin derivatives
    (Springer, 2018) Aksoy, Onder; Uzun, Ilhan; Topal, Giray; Ocak, Yusuf Selim; Celik, Omer; Batibay, Derya
    In this study, low-cost two new chitin derivatives were first synthesized. Products formed in the consequence of the reaction of chitin with 4-nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride were named C4NC and C35DC, respectively. Then, C4NC and C35DC were characterized by FTIR and C-13 CP-MAS solid-state NMR spectroscopies and X-ray powder diffraction technique. Surface topography and composition of C4NC and C35DC with a scanning electron microscope were investigated. Mass loss in C4NC and C35DC with thermogravimetric analysis method was determined as a function of increasing temperature. Endothermic and exothermic transitions in C4NC and C35DC were investigated with differential thermal analysis and differential scanning calorimetry techniques. Later on, charge carrier density, hole mobility, and electrical conductivity values of C4NC and C35DC were determined. Besides, Schottky diodes of C4NC and C35DC were constructed, and several parameters related to these diodes were determined. Finally, the sensitivity of these diodes to light was studied.