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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 Design of PV energy system in Batman Turkey(AIP Conf.Proc., 2017) Pakma, Nilay; Pakma, Osman; Güllü, ÖmerÖğe Fabrication and electrical characterization of ZnO SiO2 p Si structure with outsized diode factor(European Union, 2010) Kavasoğlu, Neşe; Kavasoğlu, Abdülkadir Sertap; Pakma, Osman; Kabakçı, Murat; Birgi, Özcan; Oktik, ŞenerÖğe Temperature dependent electrical transport in Al/Poly(4-vinyl phenol)/ p -GaAs metal-oxide-semiconductor by sol-gel spin coating method(Hindawi, 2016-03-10) Özden, Şadan; Tozlu, Cem; Pakma, OsmanDeposition of poly(4-vinyl phenol) insulator layer is carried out by applying the spin coating technique onto p-type GaAs substrate so as to create Al/poly(4-vinyl phenol)/p-GaAs metal-oxide-semiconductor (MOS) structure. Temperature was set to 80-320 K while the current-voltage (I-V) characteristics of the structure were examined in the study. Ideality factor (n) and barrier height (φ b) values found in the experiment ranged from 3.13 and 0.616 eV (320 K) to 11.56 and 0.147 eV (80 K). Comparing the thermionic field emission theory and thermionic emission theory, the temperature dependent ideality factor behavior displayed that thermionic field emission theory is more valid than the latter. The calculated tunneling energy was 96 meV.Öğe Frequency dependent interface state properties of a schottky device based on coronene deposited on n-type silicon by spin coating technique(Ulusal Fotovoltaik Teknoloji Platformu, 2016) Yüksel, Ömer Faruk; Pakma, Osman; Tuğluoğlu, NihatÖğe Control of barrier heigth ofmetal/semiconductor contacts bymolecular organic film(2011-06) Güllü, Ömer; Turut, Abdulmecit; Kılıçoğlu, Tahsin; Özerden, EniseÖğe Ag-doped HfO2 thin films via sol–gel dip coating method(Springer Nature, 2019-10-01) Pakma, Osman; Kaval, Şehmus; Kari̇per, İshak AfşinIn this study, undoped and Ag-doped HfO2 thin films were deposited on glass substrates by means of sol–gel dip coating method. These films were then thermally annealed at 500 °C for 1 h. The structural and optical properties of undoped and Ag-doped HfO2 thin films were characterized by X-ray diffraction, UV–Vis spectrometry and scanning electron microscope. The results of this analysis were compared and interpreted with the results obtained in literature by various methods of coating with HfO2. The X-ray diffraction peaks of the films paired with monoclinic HfO2 crystalline peaks. The refractive indices of the films decreased with doping Ag, at 500 nm wavelengths. The optical band gap values of Ag-doped HfO2 thin films increased with doping Ag. The porous structures were observed on the surface films, especially with 5% Ag doping.Öğe Electronic properties of the Al/Orange G/n-Si junction(2017-04) Güllü, Ömer; Arsel, İsmailÖğe Some electrical parameters of the Sn/p-Si diode under γ-irradiation(Çukurova Üniversitesi, 2017) Pakma, Osman; Güllü, ÖmerThe radiation response of metal-semiconductor (MS) contacts has been found to alter significantly when the structures are exposed to pre-irradiation processes at determined doses. Radiation doses greater than a kilogray exposure may cause strong changes on the electrical characteristics of MS structures. It has been also shown that the particle or gamma irradiations induce defects in the band gap which affects the free carrier concentration and leads to an increase and decrease of barrier height in p-type and n-type semiconductors, respectively. The knowledge of the influence of radiation damage on the Schottky barrier diodes (SBDs) performance is a fundamental field of research, having technological relevance for many applications in the semiconductor electronic devices. Hence, it is very much essential to evaluate the effect of irradiation and identify the degradation mechanism to understand the failure mechanisms. In this work, we have investigated the electrical parameters of the Sn/p-Si Schottky barrier diodes by using I-V and C-V characteristics under γ-irradiation at room temperature. The basic diode parameters such as ideality factor, barrier height, series resistance and reverse saturation current were extracted from electrical measurements as a function of the irradiation dose. The results indicated that γ-irradiation induced an increase in the effective Schottky barrier height extracted from both I-V and C-V measurements. Also, it was seen that ideality factor increased with the increasing γ-irradiation doses. We have also observed that the reverse bias current of the Sn/Si contact exceedingly decreased with increasing irradiation dose with low energy (60 keV). The basic results as related to the gamma irradiation have been indicated that this device may have applications as radiation sensors in order to detect the low energy gamma radiation.Öğe Characterization of Au N Inp photovoltaic structure with organic thin film(Uppsala University, 2012) Güllü, Ömer; Özerden, Enise; Rüzgar, Şerif; Asubay, Sezai; Pakma, Osman; Kılıçoğlu, Tahsin; Türüt, Abdulmecit
