Browsing by Author "Karabulut, A."

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Illumination Impact on the Electrical Characteristics of Au/Sunset Yellow/N-si Hybrid Schottky Diode
(Springer, 2020) Imer, A. G.; Kaya, E.; Dere, A.; Al-Sehemi, A. G.; Al-Ghamdi, A. A.; Karabulut, A.; Yakuphanoglu, F.
In this study, semiconductor device applications of organic material sunset yellow (SY) (C16H10N2Na2O7S2) has been investigated. The SY thin film was grown onn-Si via spin coating method and theAu/SY/n-Si/Auheterojunction was fabricated. The basic diode parameters of device were determined by the current-voltage (I-V) and capacitance-voltage (C-V) measurements at the room temperature. The values of the ideality factory (n) and barrier height (phi(b)) were evaluated as 1.15 and 0.70 eV, respectively; and series resistance (R-s) of device was found using Norde functions. The values of built in potential, donor concentration, Fermi energy level and barrier height were also estimated from the linearC(-2)-Vcurves with reverse bias room temperature and difference frequency. Furthermore,I-Vmeasurements were applied under different illuminations; some photoelectrical parameters of device were evaluated to understand the photo response properties of the device. Consequently, the results confirmed that the barrier height can be modified by interfacial SY layer, and the device can be used in optoelectronic applications such as optical sensor or photodiode.
Li2b4o7-Bi2o3 Glass System for Neutron Protection in Neutron Applications
(Pergamon-elsevier Science Ltd, 2023) Aygun, B.; Yorgun, N. Yildiz; Sayyed, M. I.; Karabulut, A.
In this study, new glass samples with a chemical composition of 40Li2B4O7+xBi2O3+(55-x)ZrO4+5CaWO4 (x = 10, 20, 30, 40, and 50 wt%) were fabricated using the melt quenching-annealing technique. Important neutron shielding parameters, such as the effective neutron removal cross-section, half-value layer, and neutron transmission factor, of all the new glass samples were calculated using the GEANT4 Monte Carlo simulation code. In addition, neutron dose measurements were performed using an 241Am-Be fast neutron source with an activity of 74 GBq and an average neutron energy of 4.5 MeV and a BF3 gaseous neutron detector. The results were compared with those of conventional shielding materials to determine the neutron absorption capabilities of the new glass materials. All the new glass samples were found to have excellent neutron shielding abilities. In particular, the GB5 sample had a high absorption capacity compared to the other samples. These new glass samples may be used as shielding materials in various radiation applications, such as generation of nuclear energy, radiation medicine, and the transport and storage of radioactive wastes.