Yazar "Imer, Arife Gencer" seçeneğine göre listele

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    Effect of Light Intensity and Temperature on the Current Voltage Characteristics of Al/SY/p-Si Organic-Inorganic Heterojunction
    (Springer, 2016) Imer, Arife Gencer; Ocak, Yusuf Selim
    An organic-inorganic contact was fabricated by forming a thin film of sunset yellow dye (SY) on a p-Si wafer. The device showed a good rectification property, and the sunset yellow thin film modified the barrier height (Ub) of Al/p-Si contact by influencing the space charge region. The heterojunction had a strong response to the different illumination intensities and showed that it can be suitable for photodiode applications. The I-V measurements of the device were also applied in the temperature range of 100-500 K. It was seen that characteristic parameters of the device were strongly dependent upon temperature. While the value of Ub increased, the ideality factor (n) decreased with the increase in temperature. This variation was attributed to spatial inhomogeneity at the interface. The Norde function was used to determine the temperature-dependent series resistance and Ub values, and there was a good agreement with that of ln I-V data. The values of the Richardson constant (A*) and mean Ub were determined as 29.47 A cm(-2) K-2 by means of a modified activation energy plot, matching with a theoretical one, and 1.032 eV, respectively. Therefore, it was stated that the current voltage characteristic with the temperature can be explained by thermionic emission theory with Gaussian distribution of the Ub at the interface.
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    Effects of the r-GO doping on the structural, optical and electrical properties of CdO nanostructured films by ultrasonic spray pyrolysis
    (Springer, 2020) Imer, Arife Gencer; Gulcan, Mehmet; Celebi, Metin; Tombak, Ahmet; Ocak, Yusuf Selim
    Undoped and reduced graphene oxide (r-GO)-doped CdO films were prepared via the ultrasonic spray pyrolysis method with weight ratios of 1, 3 and 5% onto substrates. The successfully prepared films were characterized to understand the influence of r-GO dopant content on the morphological, structural, electrical and optical properties of the films by several diagnostic techniques. XRD measurement confirms that all the films were polycrystalline in the cubic phase of CdO with the preferred orientation (111). The optical band gap of the films decreases with the increase in doping amount. The r-GO@CdO nanostructured films were used as an interfacial layer to fabricate the heterojunction device and to investigate their electrical properties using current-voltage and capacitance-voltage measurements in the dark. The rectification properties of the studied devices increase with the r-GO dopant amount. The obtained results indicate that the r-GO content in the CdO films is responsible for the modification of physical properties of electronic device.
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    Electrical and photoelectrical characterization of an organic-inorganic heterojunction based on quinoline yellow dye
    (Elsevier Sci Ltd, 2015) Ugur, Ali; Imer, Arife Gencer; Ocak, Yusuf Selim
    An organic-inorganic contact was fabricated by forming a thin film of quinoline yellow dye (QY) on a p-Si wafer and evaporating Al metal on the film. The current-voltage (I-V) and capacitance-voltage (C-V) measurements of Al/QY/p-Si heterostructure were applied in dark and room temperature to calculate the characteristic parameters of diode like ideality factor, barrier height and series resistance. Ideality factor and barrier height values were found as 1.23 and 0.87 eV from I-V data, respectively. The series resistance value of the device was determined as 1.8k Omega by using modified Norde function. The C-V measurements were carried out at different frequencies and it was seen that capacitance value decreased with increasing frequency. Interface state density distribution was calculated by means of I-V measurement. In addition the optical absorption of thin QY film on glass was measured and optical band gap of the film was found as 2.73 eV. Furthermore, I-V measurements of Al/QY/p-Si/Al were taken under illumination between 40 and 100 mW/cm(2). It was observed that reverse bias current of the device increased with light intensity. Thus, the heterojunction had a strong response to the light and it can be suitable for electrical and optoelectronic applications like a photodiode. (C) 2015 Elsevier Ltd. All rights reserved.
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    The novel pyridine based symmetrical Schiff base ligand and its transition metal complexes: synthesis, spectral definitions and application in dye sensitized solar cells (DSSCs)
    (Springer, 2018) Imer, Arife Gencer; Syan, Ranjdar Hamad Basha; Gulcan, Mehmet; Ocak, Yusuf Selim; Tombak, Ahmet
    The pyridine based azo-linked symmetrical Schiff base ligand, (E)-2,2'-((1E,1'E)-(pyridine-2,6-diylbis(azanylylidene))bis(methanylylidene))bis(4-((E)-phenyldiazenyl)phenol) (H2L), and its Co(II), Ni(II) and Pd(II) transition metal complexes were prepared, and defined by using elemental analysis, Fourier transform infrared, UV-visible, mass, nuclear magnetic resonance spectra, molar conductance, magnetic susceptibility and thermal analysis techniques. The conductivity results pointed out the non-electrolytic nature of all metal complexes. Elemental composition, ultraviolet spectra and magnetic susceptibility data showed that the synthesized complexes are in the binuclear structure and square plane geometry. When compared to the characteristic infrared bands for the functional groups of the ligand structure with complex molecules are reached, the ligand binds to the metal atom via phenolic OH and azomethine-nitrogen. Furthermore, the dye-sensitized solar cells (DSSCs) based on H2L and its metal complexes were fabricated, and photovoltaic properties of these devices were also investigated. The power conversion efficiency of fabricated devices based on ligand H2L can be improved with the incorporation of the transition metal complex.
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    Synthesis, Characterization, DFT Studies, and Photodiode Application of Azo-azomethine-Based Ligand and Its Transition-Metal Complexes
    (Springer, 2018) Tombak, Ahmet; Imer, Arife Gencer; Syan, Ranjdar Hamad Basha; Gulcan, Mehmet; Gumus, Selcuk; Ocak, Yusuf Selim
    An azo-azomethine-based ligand (H2L) and its transition-metal complexes were prepared, and the electronic structure of the synthesized compounds obtained computationally using density functional theory at B3LYP/6-31G (d,p) level. Furthermore, organic-inorganic heterojunctions were fabricated by forming thin films of complexes of H2L and Co(II), Ni(II), and Pd(II) metal on n-Si substrate. The fundamental electrical parameters of the rectifying heterojunctions were identified based on current-voltage data obtained in the dark at room temperature. The photosensing properties of the devices were investigated under illumination at various intensities from 40 mW/cm(2) to 100 mW/cm(2). The results showed that the photoelectrical characteristics of the devices could be modified by the thin film of metal complex, with the best photosensing properties being obtained for the heterojunction based on compound 1.