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Öğe N-type InP Schottky diodes with organic thin layer: Electrical and interfacial properties(Journal of Vacuum Science & Technology B, 2010-03) Güllü, Ömer; Turut, AbdulmecitThe rectifying junction characteristics of methyl red (MR) organic film on n-type InP substrate have been studied. It has been observed that MR-based structure shows an excellent rectifying behavior and that the MR film increases the effective barrier height by influencing the space charge region of the n-type InP. The barrier height and ideality factor values for this structure have been obtained as 0.75 eV and 1.93 from the forward bias current-voltage characteristics, respectively. By using capacitance-voltage characteristics at 1 MHz, the barrier height and the carrier concentration values have been calculated as 0.93 eV and 5.13×1015 cm−3, respectively. The energy distributions of the interface states and their relaxation times have been determined from the forward bias capacitance-frequency and conductance-frequency characteristics. Moreover, it was seen that both the interface-state density and the relaxation time of the interface states decreased with bias voltage from experimental results.Öğe Electrical analysis of organic dye based MIS Schottky contacts(Microelectronic Engineering, 2010-05-25) Güllü, Ömer; Turut, AbdulmecitIn this work, we prepared metal/interlayer/semiconductor (MIS) diodes by coating of an organic film onp-Si substrate. Metal(Al)/interlayer(Orange G@OG)/semiconductor(p-Si) MIS structure had a good recti-fying behavior. By using the forward-biasI–Vcharacteristics, the values of ideality factor (n) and barrierheight (BH) for the Al/OG/p-Si MIS diode were obtained as 1.73 and 0.77 eV, respectively. It was seen thatthe BH value of 0.77 eV calculated for the Al/OG/p-Si MIS diode was significantly larger than the value of0.50 eV of conventional Al/p-Si Schottky diodes. Modification of the potential barrier of Al/p-Si diode wasachieved by using thin interlayer of the OG organic material. This was attributed to the fact that the OGorganic interlayer increased the effective barrier height by influencing the space charge region of Si. Theinterface-state density of the MIS diode was found to vary from 2.79x1013to 5.80x1012eVx1cmx2.Öğe Electronic properties of the metal organic interlayer inorganic semiconductor sandwich device(Elsevier, 2010-03) Güllü, Ömer; Turut, Abdulmecit; Kılıçoğlu, TahsinIn 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 (Φb) for the Al/CR/p-Si MIS device were obtained as 1.68 and 0.77 eV, respectively. It was seen that the Φb 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 1.24×1013 to 2.44×1012 eV−1 cm−2.Öğe Electrical properties of organic–ınorganic semiconductor device based on rhodamine-101(SpringerLink, 2009-05) Güllü, Ömer; Turut, Abdulmecit; Yıldırım, Nezir; Çakar, MuzafferRhodamine-101 (Rh101) thin films on n-type Si substrates have been formed by means of evaporation, thus Sn/Rh101/n-Si heterojunctions have been fabricated. The Sn/Rh101/n-Si devices are rectifying. The optical energy gaps have been determined from the absorption spectra in the wavelength range of 400 nm to 700 nm. Rh101 has been characterized by direct optical absorption with an optical edge at 2.05 ± 0.05 eV and by indirect optical absorption with␣an optical edge at 1.80 ± 0.05 eV. It was demonstrated that trap-charge-limited current is the dominant transport mechanism at large forward bias. A␣mobility value of μ = 7.31 × 10−6 cm2 V−1 s−1 for Rh101 has been obtained from the forward-bias current–voltage characteristics.Öğe Electrical properties of safranine T p Si organic inorganic semiconductor devices(Cambridge University, 2010-04-25) Güllü, Ömer; Asubay, Sezai; Biber, Mehmet; Kılıçoğlu, Tahsin; Turut, AbdulmecitWe 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)×1014 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.Öğe Determination of the laterally homogeneous barrier height of thermally annealed and unannealed Au/p-InP/Zn-Au Schottky barrier diodes(Elsevier, 2008-03-25) Güllü, Ömer; Turut, Abdulmecit; Asubay, SezaiWe have identically prepared Au/p-InP Schottky barrier diodes (SBDs). The diodes were annealed up to 400 °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 °C annealing has been ascribed to the formation of the excess charges that electrically actives on the semiconductor surface.
