Yazar "Al-Ghamdi, Ahmed A." seçeneğine göre listele

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    Cadmium Oxide:Titanium Dioxide Composite Based Photosensitive Diode
    (Springer, 2018) Karabulut, Abdulkerim; Dere, A.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.
    Cadmium oxide:titanium dioxide (CdO:TiO2) composite thin films with various ratios of CdO contents were prepared on p-type silicon semiconductor substrates by the sol-gel spin coating method. Al/CdO:TiO2/p-Si/Al heterojunction devices exhibited optoelectronic device behavior due to their photocurrent under solar light illuminations. The photoresponse behavior of the diodes is controlled by changing the molar ratio of CdO to TiO2. The fabricated CdO:TiO2 (2:1) based device exhibited the highest photoresponse of about 7.5 x 10(3). The interface properties of the devices are changed with the molar ratio of CdO:TiO2. The obtained results suggest that CdO:TiO2 composite film/p-type Si structure can be used in optoelectronic applications.
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    Electronic and optoelectronic properties of Al/coumarin doped Pr2Se3-Tl2Se/p-Si devices
    (Springer, 2018) Tataroglu, A.; Ahmedova, C.; Barim, G.; Al-Sehemi, Abdullah G.; Karabulut, Abdulkerim; Al-Ghamdi, Ahmed A.; Farooq, W. A.
    In this study, coumarin-doped Pr2Se3-Tl2Se (0.00, 0.05, 0.1, 0.3 wt% coumarin) were covered on the front side of a p-Si substrate by drop coating method and thus Al/coumarin doped Pr2Se3-Tl2Se/p-Si diodes were fabricated. The electronic and optoelectronic properties of the prepared diodes were investigated. The highest rectification ratio (RR = I-F/I-R) value was found to be 2.24 x 10(5) for the diode having 0.05 wt% coumarin doping at dark and +/- 5 V. Also, the highest I-photo/I-dark photosensitivity was found to be 1327 for the diode which has 0.1 wt% coumarin doping at 100 mW/cm(2) and - 5 V. The photocurrent of the diodes is higher than the dark current and increases by the increase of the light intensity. These results confirm that the fabricated diodes show a strong photovoltaic behavior. The electronic parameters of the diodes, for example ideality factor and barrier height values, were calculated by the use of current-voltage characteristics. The transient measurement proves that the diodes show both photodiode and photocapacitor behaviors. The change on the conductance and capacitance by the frequency is attributed to the existence of interface states. Thus, the obtained results suggest that the prepared diodes might be used as a photosensor in the applications of optoelectronic.
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    Photodiode based on Pb0.9Cd0.1S ternary alloy semiconductor for solar tracking systems
    (Springer, 2018) Wageh, S.; Karabulut, Abdulkerim; Dere, A.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; El-Tantawy, Farid; Yakuphanoglu, F.
    The fabrication and photoelectrical properties of the photodiodes based on the ternary alloy of semiconductor nanocrystallite Pb0.9Cd0.1S with coumarin dopant were investigated. The structure, stability, melting temperature and optical bandgap of the prepared nanostructure were characterized by X-ray diffraction, thermogravimetric analysis, Infrared, Raman spectroscopy and UV-VIS-NIR spectroscopies. The characterization of the ternary alloy indicates that the crystal structure of the ternary alloy is cubic with some distortion in (111) direction and has a nanosize of 9 nm. The photoelectrical characteristics of fabricated Si-based photodiodes with coumarin doped PbCdS interfacial layers were investigated by using current-voltage, transient photocurrent and capacitance/conductance-voltage measurements. Some electrical parameters and the effects of illumination on these parameters have been determined from these measurements. Consequently, results of experiments suggest that the ternary alloy Pb0.9Cd0.1S nanocrystallite based photodiode can be suitable for optoelectronic applications.
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    Silicon based photodetector with Ru(II) complexes organic interlayer
    (Elsevier Sci Ltd, 2019) Karabulut, Abdulkerim; Dere, A.; Dayan, Osman; Al-Sehemi, Abdullah G.; Serbetci, Z.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.
    In present work, the electrical properties and illumination effects were investigated for the silicon based photodetector with organic Ru(II) complexes interfacial layer. The current-voltage (I-V) and capacitance/conductance-voltage (C/G-V) measurements were analyzed to determine electrical and photoelectrical properties under dark and different solar light intensity conditions. The reverse bias current values under light conditions were higher than dark conditions, and this situation demonstrates that the fabricated device displays a photo conducting behavior. Besides, some crucial electrical parameters such as series resistance, barrier height and ideality factor values of prepared device were calculated by using current-voltage measurements. The ideality factor and barrier height values of fabricated device were calculated as 9.42 and 0.59 for dark condition. Besides to these experiments, transient photocurrent and photo-capacitance/conductance were also investigated under different light conditions. It was determined from transient measurements that the fabricated device has a high sensitivity to light. The photoresponse of the diode was determined to be around 4479 +/- 1.9 under 100 mW/cm(2 )illumination. The examined C/G-V characteristics of the fabricated device strongly depend on voltage and frequency. The analyzed results suggest that the fabricated Al/Ru(II) complexes/p-Si/Al device can be used in rapidly developing optoelectronic applications, especially for the organic materials-based photodetector technology.