Yazar "Turut, A." seçeneğine göre listele

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    Determination of the laterally homogeneous barrier height of metal/p-InP Schottky barrier diodes
    (Pergamon-Elsevier Science Ltd, 2009) Asubay, S.; Gullu, O.; Turut, A.
    We have reported a study of a number of metal/p-type InP (Cu, Au, Al, Sn, Pb, Ti, Zn) Schottky barrier diodes (SBDs). Each one diode has been identically prepared on p-InP under vacuum conditions with metal deposition. In Schottky diodes, the current transport occurs by thermionic emission over the Schottky barrier. The current-voltage characteristics of Schottky contacts are described by two fitting parameters such as effective barrier height and the ideality factor. Due to lateral inhomogeneities of the barrier height, both characteristic diode parameters differ from one diode to another. We have determined the lateral homogeneous barrier height of the SBDs from the linear relationship between experimental barrier heights and ideality factors that can be explained by lateral inhomogeneity of the barrier height. Furthermore, the barrier heights of metal-semiconductor contacts have been explained by the continuum of metal-induced gap states (MIGS). It has been seen that the laterally homogeneous barrier heights obtained from the experimental data of the metal/p-type InP Schottky contacts quantitatively confirm the predictions of the combination of the physical MIGS and the chemical electronegativity. (C) 2009 Elsevier Ltd. All rights reserved.
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    Determination of the laterally homogeneous barrier height of thermally annealed and unannealed Au/p-InP/Zn-Au Schottky barrier diodes
    (Elsevier, 2008) Asubay, S.; Gullu, O.; Turut, A.
    We have identically prepared Au/p-InP Schottky barrier diodes (SBDs). The diodes were annealed up to 400 degrees C thermally. The barrier height (BH) for the as-deposited Au/p-InP/Zn-Au SBDs from the current-voltage characteristics have varied from 0.58 to 0.72 eV, and ideality factor n from 1.14 to 1.47. The BH for the annealed SBDs from the current-voltage characteristics have varied from 0.76 to 0.82 eV, and ideality factor n from 1.17 to 1.39. As a result of the thermal annealing, it has been seen that the BH values of the annealed SBDs are larger than those of the as-deposited SBDs. We have determined a lateral homogeneous BH value of 0.72 eV for the as-deposited Au/p-InP SBD from the experimental linear relationship between barrier heights and ideality factors, and a value of 0.85 eV for the annealed Au/p-InP SBD. The increase of 0.13 eV in the BH value by means of 400 degrees C annealing has been ascribed to the formation of the excess charges that electrically actives on the semiconductor surface. (C) 2007 Elsevier B.V. All rights reserved.
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    The electrical characteristics of sn/methyl-red/p-type Si/Al contacts
    (Elsevier, 2007) Aydin, M. E.; Turut, A.
    The junction characteristics of the organic compound methyl-red film (2-[4-(dimethylamino)phenylazo]benzoic acid) on a p-type Si substrate have been studied. The current-voltage characteristics of the device have rectifying behavior with a potential barrier formed at the interface. The barrier height and ideality factor values of 0.73 eV and 3.22 for the structure have been obtained from the forward bias current-voltage (I-V) characteristics. The interface state energy distribution and their relaxation time have ranged from 1.68 x 10(12) cm(-2) eV(-1) and 1.68 x 10(-3) s in (0.73-E-v) eV to 1.80 x 10(12) cm(-2) eV(-1) and 5.29 x 10(-5) s in (0.43-E-v) eV, respectively, from the forward bias capacitance-frequency and conductance-frequency characteristics. Furthermore, the relaxation time of the interface states shows an exponential rise with bias from (0.43-E-v) eV towards (0.73-Ev) eV. (C) 2007 Elsevier B.V. All rights reserved.
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    Electrical characterization of the Al/new fuchsin/n-Si organic-modified device
    (Elsevier, 2010) Gullu, O.; Asubay, S.; Aydogan, S.; Turut, A.
    The current-voltage (I-V) and the capacitance-voltage (C-V) characteristics of the Al/new fuchsin (NF)/n-Si device have been investigated at room temperature. The I-V characteristic of the device shows a good rectification. The ideality factor and the barrier height from the I-V characteristics have been determined as 3.14 and 0.80 eV, respectively. A modified Norde's function combined with the conventional I-V method has been used to extract the parameters including the barrier height and the series resistance. The barrier height and the series resistance obtained from Norde's function have been compared with those from Cheung functions, and it has been seen that there was a good agreement between those from both method. It has also been seen that the values of diode capacitance increased up to the constant values for the forward bias. (C) 2009 Elsevier B.V. All rights reserved.
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    Electrical properties of safranine T/p-Si organic/inorganic semiconductor devices
    (Edp Sciences S A, 2010) Gullu, O.; Asubay, S.; Biber, M.; Kilicoglu, T.; Turut, A.
    We investigated the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of identically prepared safranine T/p-Si organic/inorganic Schottky devices (total 26 diodes) formed by evaporation of organic compound solution on p-Si semiconductor substrate. It was seen that the safranine T organic thin film on the p-Si substrate showed a good rectifying behavior. The barrier heights and ideality factors of all devices were extracted from the electrical characteristics. The mean barrier height and mean ideality factor from I-V measurements were calculated as 0.59 +/- 0.02 eV and 1.80 +/- 0.20, respectively. Also, the mean barrier height and mean acceptor doping concentration from C-V measurements were calculated as 0.67 +/- 0.10 eV and (6.96 +/- 0.37) x10(14) cm(-3), respectively. The discrepancy in the barrier height values obtained from I-V and C-V characteristics has been attributed to different nature of the measurements. The discrepancy between these values can also be due to the existence of the interfacial native oxide and the organic safranine T thin layer between the semiconductor substrate and top contact metal.
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    Electronic properties of the metal/organic interlayer/inorganic semiconductor sandwich device
    (Pergamon-Elsevier Science Ltd, 2010) Gullu, O.; Kilicoglu, T.; Turut, A.
    In this study, we prepared a Metal(Al)/Organic Interlayer(Congo Red=CR)/Inorganic Semiconductor (p-Si) (MIS) Schottky device formed by coating of an organic film on p-Si semiconductor wafer. The Al/CR/p-Si MIS device had a good rectifying behavior. By using the forward bias I-V characteristics, the values of ideality factor (n) and barrier height (Phi(b)) for the Al/CR/p-Si MIS device were obtained as 1.68 and 0.77 eV, respectively. It was seen that the Phi(b) value of 0.77 eV calculated for the Al/CR/p-Si MIS device was significantly higher than value of 0.50 eV of the conventional Al/p-Si Schottky diodes. Modification of the interfacial potential barrier of the Al/p-Si diode was achieved by using a thin interlayer of the CR organic material. This was attributed to the fact that the CR organic interlayer increased the effective barrier height by influencing the space charge region of Si. The interface-state density of the MIS diode was found to vary from 1.24 x 10(13) to 2.44 x 10(12) eV(-1) cm(-2). (C) 2009 Elsevier Ltd. All rights reserved.