Yazar "Tecimer, Habibe Uslu" seçeneğine göre listele

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    Comparative study of the effect of different interlayer thicknesses on frequency dependent electric modulus and conductivity in Au/n-Si structures
    (Elsevier Science Sa, 2021) Arslan, Bilal; Tan, Serhat Orkun; Orak, Ikram; Tecimer, Habibe Uslu
    Frequency dependent capacitance (C) and conductance (G/omega) data for Au/n-Si structures fabricated at room temperature without interlayers and with 5 nm and 10 nm aluminium-oxide (Al2O3) interlayer thicknesses are investigated. The Al2O3 interlayers were deposited by atomic layer deposition. Data on the complex electric modulus (M*) and alternating current electrical conductivity (sigma(ac)) values are acquired for the three structures in the 3 kHz-3 MHz frequency range between (-3 V) - (+5 V) bias interval and compared. It was observed that the C and G/omega values decreased with the increase in frequency and interlayer thickness and that the frequency increases as a result of polarization which also increases M*, especially in 5 nm and 10 nm interlayered structures. Frequency and interlayer thickness increment have a positive impact by increasing sigma(ac), while conductivity has been shown to be highly sensitive to the presence of an interlayer and to its thickness.
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    Determination of temperature sensitivity and current-transport mechanisms of the GaAs-based MS contact
    (Elsevier, 2023) Kaymaz, Ahmet; Baydilli, Esra Evcin; Tecimer, Hueseyin; Tecimer, Habibe Uslu; Altindal, Semsettin
    In this study, the GaAs-based metal-semiconductor (MS) contact was prepared as a reference sample for com-parison with other devices in the literature, especially some interfacial layered Schottky structures and tem-perature sensors. The study also includes investigating and evaluating essential device parameters for determining current-transport mechanisms (CTMs) and temperature-sensing behavior. In fact, the benefits of the insulator/organic interfacial layer in devices, such as controlling charge transfers and preventing diffusion at the MS interface, have been mentioned a lot in the literature. However, since the production processes of the MS contact are easier and less costly than interfacial-layered devices, it would be more logical/suitable to prefer it in applications where this device may be sufficient, especially as a temperature sensor. Therefore, the current-voltage (I-V) data of the produced MS contact was obtained in a wide temperature range to determine the CTMs, and it was observed that two linear areas with different slopes, known as the two-parallel diode model, existed in the GaAs-based MS contact. Therefore, essential contact parameters and graphs were obtained for both two regions, and it was obtained that quantum mechanical tunneling mechanisms, the T0 effect, and the Double Gaussian Distribution (DGD) with Thermionic Emission theory play a role as CTMs of the GaAs-based MS contact such as some interfacial layered devices given in the literature. On the other hand, the temperature sensitivity of the MS contact was examined, and it was observed that the sensitivity parameter values exhibit an excellent quality sensing behavior compared to other devices in the literature, including devices with high-temperature sensitivity. Therefore, it can be preferred as a temperature sensor in many applications due to its low cost and easy production processes.
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    Dielectric characterization of BSA doped-PANI interlayered metal-semiconductor structures
    (Springer, 2019) Karaoglan, Nursel; Tecimer, Habibe Uslu; Altindal, Semsettin; Bindal, Cuma
    The measured capacitance and conductance-voltage (C & G/omega-V) data between 1 and 200 kHz of Al/(BSA-doped-PANI)/p-InP structure were examined to uncover real and imaginary components of complex permittivity (epsilon* = epsilon ' - j epsilon ''), loss tangent (tan delta), complex electric modulus (M* = M ' + jM ''), and electrical conductivity (sigma). It was uncovered that dielectric constant (epsilon '), dielectric loss (epsilon ''), tan delta, real and imaginary components (M ' and M '') show a big dispersive behavior at low frequencies due to the oriental and the interfacial polarizations, as well as the surface states (N-ss) and the BSA doped-PANI interlayer. Such behavior in epsilon ', epsilon '', and tan delta, behavior with frequency was also explained by Maxwell-Wagner relaxation. The values of sigma are almost constant at lower-intermediate frequencies, but they start increase at high frequencies which are corresponding to the dc and ac conductivity, respectively. The values of M ' and M '' are lower in the low frequency zone and they become increase with increasing frequency at accumulation region due to the short-range charge carriers mobility. Ultimately, dielectric parameters and electric modulus alteration with frequency is the consequence of surface states and relaxation phenomena.
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    Evaluation of gamma-irradiation effects on the electrical properties of Al/(ZnO-PVA)/p-Si type Schottky diodes using current-voltage measurements
    (Pergamon-Elsevier Science Ltd, 2021) Kaymaz, Ahmet; Baydilli, Esra Evcin; Tecimer, Habibe Uslu; Altindal, Semsettin; Azizian-Kalandaragh, Yashar
    In this study, Al/(ZnO-PVA)/p-Si (MPS) type Schottky diodes (SDs) were produced and the radiation effects on their electrical properties were investigated using the current-voltage (I?V) measurements. The I?V measurements were performed before irradiation and after various irradiation doses in the wide voltage range (?4 V) at room temperature. To determine gamma-irradiation effects on the MPS-type SDs accurately, one SD was preferred as a sample, and its significant electrical parameters such as zero-bias barrier height (?B0), ideality factor (n), and reverse-saturation-current (I0) were calculated using the linear parts of the ln(I)?V characteristics. Besides, to observe the effects of gamma-rays on MPS-type SDs in different voltage regions, some diode parameters were obtained by different calculation methods such as Cheung and Norde functions as well as Thermionic Emission (TE) theory. The calculations showed that high doses of gamma-irradiation (>5 kGy) caused the annealing effect, which leads to an improvement in some electrical parameters of SD, especially in the high electric field region. On the other hand, the energy distribution of the surface states (Nss) was obtained by utilizing the voltage-dependent ideality factor and the effective barrier height, with and without considering the series resistance (Rs) effect. It was observed that Nss values decreased almost as exponentially from the mid-band gap of the semiconductor towards the upper edge of the valance-band. Also, the density of surface states decreased with increasing radiation doses. As a result, almost all diode parameters are affected by irradiation. However, no significant defect has been detected that would affect the stable operation of the diode. Hence, Al/ (ZnO-PVA)/p-Si type SD can be used as an MPS-type detector instead of MIS/MOS-type detectors due to some advantages of the organic/polymer interlayer such as being cheap, light per molecule, flexible and requiring low energy consumption.
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    The Impact of Dopant on the Dielectric Properties of Metal-Semiconductor With ZnFe2O4 Doped Organic Polymer Nanocomposites Interlayer
    (Ieee-Inst Electrical Electronics Engineers Inc, 2022) Alsmael, Jaafar Abdulkareem Mustafa; Tan, Serhat Orkun; Tecimer, Habibe Uslu; Altindal, Semsettin; Kalandaragh, Yashar Azizian
    In this research, the dielectric characteristics of fabricated Al/(ZnFe2O4-PVA)/p-Si structures have been investigated in wide range frequency and voltage. Thus, by deriving capacitance-conductance (C-G/omega) measurements the main parameters of the metal-polymer-semiconductor (MPS) structure such as complex dielectric constants (epsilon ' and epsilon ''), loss tangent (tan delta), complex electric modulus (M ' and M '') and ac electrical conductivity (sigma(ac)), were acquired at frequency and voltage ranges of 1 kHz-1 MHz and (+/- 5V). As a result of the experiment, it was observed that the presence of negative capacitance (NC) at low frequencies differently affects the dielectric properties of the structure. Although the NC effect disappeared at high frequencies by the reduction of the effect of many parameters such as series resistance (R-ss) and interface states (N-ss) with frequency increment, the dielectric properties of the structure varied especially in the reverse bias region. Ultimately, it has been observed that the dielectric properties of the structure are highly dependent on frequency, voltage, N-ss, and polarization.
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    Integration of Zn-doped organic polymer nanocomposites between metal semiconductor structure to reveal the electrical qualifications of the diodes
    (Springer, 2018) Tecimer, Habibe Uslu; Alper, M. A.; Tecimer, H.; Tan, S. O.; Altindal, S.
    Schottky barrier diodes (SBDs) have been fabricated with pure and zinc (Zn) doped organic interfacial layer of polyvinyl alcohol (PVA) to form Au/PVA/n-GaAs and Au/PVA(Zn-doped)/n-GaAs structures. The electrical characterization of these SBDs have also been made using their current-voltage (I-V) characteristics data on both forward and reverse biases at room temperature. The main electrical parameters, such as ideality factor (n), barrier height (I broken vertical bar (Bo)), series resistance (R (s)) and the voltage dependence resistance (R (i)) have also been extracted from the I-V data to compare the Zn-doped and undoped polymer interfacial layer SBDs. The rectifying ratio values of Au/PVA/n-GaAs and Au/PVA(Zn-doped)/n-GaAs SBDs have been obtained as 10(5) and 10(7), respectively, at (+/- 2 V). Consequently, the comparison of the polymer interfacial layer SBDs indicates that the Zn-doped SBDs have given better results than the undoped SBDs when considering the main electrical parameters at room temperature.
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    Investigation of gamma-irradiation effects on electrical characteristics of Al/(ZnO-PVA)/p-Si Schottky diodes using capacitance and conductance measurements
    (Springer, 2020) Kaymaz, Ahmet; Tecimer, Habibe Uslu; Baydilli, Esra Evcin; Altindal, Semsettin
    In this study, Al/(ZnO-PVA)/p-Si (MPS type) Schottky diodes (SDs) were fabricated instead of metal-semiconductor (MS) type SDs with traditional insulator interfacial layer. Additionally, basic electrical parameters of these MPS-type SDs (such as doping acceptor atoms (N-A), depletion layer width (W-D), series resistance (R-s), barrier height (phi(B)), and surface states/traps (N-ss/N-it)) were found as a function of gamma-irradiation by using the capacitance/conductance-voltage (C/G-V) measurements. These measurements under 0-60 kGy radiation doses show that radiation-induced N-ss are more effective in the depletion layer. On the other hand, voltage-dependent profiles of R-s and N-ss were also obtained using Nicollian-Brews and Castagne-Vapaille methods, respectively. Additionally, the C/G-V characteristics were corrected before irradiation and after 60 kGy doses by considering the effects of R-s. These calculations show that R-s is more effective especially in the accumulation region and therefore, it must be considered in the calculations. All these results have indicated that MS-type SDs with (ZnO-PVA) polymer interfacial layer are very sensitive to gamma-irradiation. Hence, they can be successfully used as MPS-type detectors instead of MIS/MOS-type detectors. Hence, they can be successfully used as MPS-type detectors instead of MIS/MOS-type detectors, since polymer layers can be easily grown compared to insulator/oxide layers. Also, they are cheaper, lighter, more flexible, and require low energy consumption. In conclusion, it can be said that although all parameters were affected by gamma-irradiation, no significant defect/deterioration was observed in applied dose range which would hinder the operation of these MPS-type SDs.