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Comparison of dielectric characteristics for metal-semiconductor structures fabricated with different interlayers thicknesses
(Springer, 2021) Arslan, Bilal; Tan, Serhat Orkun; Tecimer, Huseyin; Altindal, Semsettin
The dielectric properties of MS structures without interlayer and with Al2O3 interlayer have been investigated in a wide frequency range under forward and reverse biases. In this context, parameters such as loss tangent (tan delta), dielectric constant (epsilon '), dielectric loss (epsilon '') were calculated from the capacitance and conductivity data. The observed changes in dielectric parameters have been attributed to the coupling mechanisms between charges placed at the interface states, surface and bipolar polarization, and traps. The experimental results clearly indicate that the values of epsilon ', epsilon '' and tan delta vary significantly with frequency and voltage. That is, the thickness of the interlayer changes considerably the dielectric properties of the structure. As a result, it has been revealed that the desired device properties can be achieved by varying the thickness of the interlayers.
Determination of Surface States Energy Density Distributions and Relaxation Times for a Metal-Polymer-Semiconductor Structure
(Ieee-Inst Electrical Electronics Engineers Inc, 2019) Alptekin, Sebahaddin; Tan, Serhat Orkun; Altindal, Semsettin
The capacity/conductivity-voltage (C/G-V) data of the PVP interlayered metal-semiconductor structure were examined at +/- 4V biases and 1-500 kHz frequency interval at room temperature. The surface states (N-ss) in the insulation layer and the metal-semiconductor interface are seen as the main causes of high capacitance and conductivity values at low frequencies. AC signals, which result in an increase in capacitance and conductivity values, are easily monitored by N-ss at low frequencies. The graph extracted against the conductivity and frequency logarithm (G(p)/omega-log(f)) indicates a peak appearance as a result of the N-ss effect. In the energy range of (E-c -0.423) - (E-c-0.604), surface states (N-ss) and relaxation times (tau) values alter from 8.71 x 10(11) to 5.84 x 10(11) eV(-1) cm(-2) and 6.54x10(-6) s to 1.10x10(-4) s, respectively.
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.
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.
Dielectric properties, electric modulus and conductivity profiles of Al/Al2O3/p-Si type MOS capacitor in large frequency and bias interval
(Elsevier - Division Reed Elsevier India Pvt Ltd, 2022) Tan, Serhat Orkun; Cicek, Osman; Turk, Cagri Gokhan; Altindal, Semsettin
The letter reports that the impedance spectroscopy method has been performed to acquire impeccable results on the ac electric conductivity (sigma(ac)) dielectric (epsilon' and epsilon '') and electric modulus (M' and M '') components of the Al/Al2O3/p-Si type MOS capacitor. The relevant parameters are defined with C-V-f and G/omega-V-f data between 1 kHz and 5 MHz and +/- 3 V at room temperature. Both parts of dielectric constants are decreasing at high frequencies to prevent the interface dipoles from gaining enough time to return to the alternative area. Depending on the restructuring and reorganization of surface states (N-ss) in the alternative field, tan delta decreases at higher frequencies. The M' values reach maximum by frequency increment in the depletion region, while M '' values shift to the forward biases depending on a certain density distribution of N-ss. The sigma(ac) values increase with increasing frequency in the accumulation region depending on series resistance. Considering polarization processes, surface conditions (N-ss) and Al2O3 interlayer, frequency and biases are extremely effective and dependent on the dielectric specifications, electrical modulus and conductivity. (C) 2021 Karabuk University. Publishing services by Elsevier B.V.
The effect of gamma irradiation on electrical and dielectric properties of organic-based Schottky barrier diodes (SBDs) at room temperature
(Pergamon-Elsevier Science Ltd, 2012) Uslu, Habibe; Yildirim, Mert; Altindal, Semsettin; Durmus, Perihan
The effect of Co-60 (gamma-ray) irradiation on the electrical and dielectric properties of Au/Polyvinyl Alcohol (Ni,Zn-doped)/n-Si Schottky barrier diodes (SBDs) has been investigated by using capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements at room temperature and 1 MHz. The real capacitance and conductance values were obtained by eliminating series resistance (R-s) effect in the measured capacitance (C-m) and conductance (G(m)) values through correction. The experimental values of the dielectric constant (epsilon'), dielectric loss (epsilon ''), loss tangent (tan delta), ac electrical conductivity (sigma(ac)) and the real (M') and imaginary (M '') parts of the electrical modulus were found to be strong functions of radiation and applied bias voltage, especially in the depletion and accumulation regions. In addition, the density distribution of interface states (N-ss) profile was obtained using the high-low frequency capacitance (C-HF-C-LF) method for before and after irradiation. The N-ss-V plots give two distinct peaks for both cases, namely before radiation and after radiation, and those peaks correspond to two different localized interface states regions at M/S interface. The changes in the dielectric properties in the depletion and accumulation regions stem especially from the restructuring and reordering of the charges at interface states and surface polarization whereas those in the accumulation region are caused by series resistance effect. (C) 2011 Elsevier Ltd. All rights reserved.
The effects of (Bi2Te3-Bi2O3-TeO2-PVP) interfacial film on the dielectric and electrical features of Al/p-Si (MS) Schottky barrier diodes (SBDs)
(Elsevier, 2020) Altindal, Semsettin; Farazin, Javid; Pirgholi-Givi, Gholamreza; Maril, Elif; Azizian-Kalandaragh, Yashar
The influence of the inorganic/organic interfacial layer on the electric and dielectric performance of both Al/p-Si (MS) and Al/(Bi2Te3- Bi2O3- TeO2- PVP)/p-Si (MPS) type SBDs have been investigated. The material for the interfacial layer has been synthesized by the ultrasound-assisted method. FE-SEM, XRD, EDS, and UV-Vis techniques have been used for structural and optical characteristics of the prepared sample. The main electrical, dielectric, and electrical modulus parameters of these SBDs were obtained from the I-V and impedance spectroscopy measurements and using different calculation methods. The surface states (N-ss) have been calculated. The real and imaginary components of the permittivity (epsilon* = epsilon'-j epsilon ''), complex modulus (M* = M' +jM ''), dielectric loss tangent, and conductivity (sigma(ac)) values were also calculated from the (C/G-f) measurements in the wide range of frequency(100Hz-1MHz). We observed that (Bi2Te3-Bi2O3-TeO2-PVP) interlayer may be a good alternative to the low-dielectric insulator prepared by traditional methods.
Effectuality of Barrier Height Inhomogeneity on the Current-Voltage-Temperature Characteristics of Metal Semiconductor Structures with CdZnO Interlayer
(Springer, 2018) Tascioglu, Ilke; Tan, Serhat Orkun; Yakuphanoglu, Fahrettin; Altindal, Semsettin
Current-conduction/transport mechanisms (CCMs or CTMs) through barrier and barrier height (BH) formation in the Al/(CdZnO)/p-Si/Al diodes, which were prepared by the sol-gel method, were examined in the range of 110-380 K. The decrease of zero-bias BH (Phi(Bo)) and increase of ideality factor (n) with decreasing temperature were observed. The classic Richardson plot indicated two distinct linear regions that correspond to low and high temperature range (LTR and HTR), respectively. Contrary to this, the acquired Richardson constant value (A*) was much lower than its theoretical value (32 A cm(-2) K-2). Such abnormal behavior of the Phi(Bo), n and A* was attributed to the evidence of the barrier inhomogeneities, especially at low temperature. Therefore, the Phi(Bo-)n, Phi(Bo) and (n(-1) - n) versus q/2kT plots were sketched to acquire significant clues for the Gaussian distribution (GD) of the BHs at rectifier contact area with the mean BH ((Phi) over bar (Bo)) and standard deviation (sigma(so)), which also have two linear parts with distinct slopes. (Phi) over bar and sigma(so) were calculated from the slope and intercept of Phi(Bo) versus q/2kT plot as 0.802 eV and 0.066 V for LTR, 1.043 eV and 0.106 V for HTR, respectively. The (Phi) over bar (Bo) and A* were acquired by utilizing the sigma(so) values and using the Richardson plot as 0.626 eV and 14.26 A cm(-2) K-2 for LTR and 1.021 eV and 32.53 A cm(-2) K-2 for HTR, respectively. Thus, the I-V-T characteristics of the Al/(CdZnO)/p-Si/Al diodes at forward biases were successfully elucidated by the double-GD of BHs with mean BHs of 0.626 eV and 1.021 eV, respectively.
Evaluation of Electric and Dielectric Properties of Metal-Semiconductor Structures With 2% GC-Doped-(Ca3Co4Ga0.001Ox) Interlayer
(Ieee-Inst Electrical Electronics Engineers Inc, 2018) Maril, Elif; Tan, Serhat Orkun; Altindal, Semsettin; Uslu, Ibrahim
Electrical and dielectric properties of Au/n-Si metal-semiconductor structures with high dielectric have been examined by capacitance/conductance-voltage (C/G-V) measurements in the frequency range of 5-500 kHz at room temperature. Voltage-dependent profiles of interface states (N-ss) and resistance (R-i) were extracted from the C and G data using the low-high-frequency capacitance and Nicollian-Brews methods, respectively. The real and imaginary components of the complex dielectric constant (epsilon', epsilon ''), electric modulus (M' and M ''), and ac conductivity (sigma(ac)) were calculated from the C and G data. All parameters have a strong relation with frequency and voltage, especially at low frequencies due to Maxwell-Wagner relaxation and N-ss. The observed peaks in the N-ss-V and R-i-V plots can be ascribed by the special distribution of N-ss at M/S interface. These results confirmed that [2% graphene cobalt-doped (Ca3CO4Ga0.001Ox] interlayer has high-dielectric constant and can be used an interlayer instead of the traditional SiO2 at M/S interface to increase their capacitance or more charges/energy storage and reduce both the values of N-ss and series resistance (R-s). The values of a are almost constant at lower-intermediate frequencies, but they start to increase at high frequencies that are corresponding to the dc and ac conductivity, respectively.
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.
Frequency and voltage dependence of barrier height, surface states, and series resistance in Al/Al2O3/p-Si structures in wide range frequency and voltage
(Elsevier, 2020) Turk, Cagri Gokhan; Tan, Serhat Orkun; Altindal, Semsettin; Inem, Burhanettin
In this study, Al/Al2O3/p-Si (MIS) type structures were fabricated and then the effects of Al2O3 interlayer on the electrical characteristics have been investigated at room temperature. For this purpose, capacitance/ conductance-voltage-frequency (C/G-V-f) measurements were performed in the wide range frequency (1kHz-5 MHz) and voltage (+/- 3 V) to get more reliable and accuracy results on the barrier height (BH) formation at Al/p-Si interface, conduction mechanisms, and main electrical parameters. Experimental results indicate that C and G/omega values are strong function of frequency and voltage particularly in the regions of accumulation and depletion. Calculating from the interception and slope of C-2-V plot, the doping acceptor atoms (N-A), BH and depletion layer width (W-D) were obtained for each frequency, respectively. Both BH and W-D values exponentially increase by frequency increment. Nicollian-Brews method were used to extract voltage dependence profiles of R-s and frequency from C and G data.
Frequency dependent electrical and dielectric properties of the Au/(RuO2: PVC)/n-Si (MPS) structures
(Elsevier, 2023) Guneser, Muhammet Tahir; Elamen, Hasan; Badali, Yosef; Altindal, Semsettin
In this study, the electrical and dielectric characteristics of the Au/(RuO2:PVC)/n-Si structures were analyzed using the impedance spectroscopy method, including capacitance/conductance (C - G/omega) measurements in wide voltage and frequency ranges (+4 V, 5 kHz - 5 MHz) at room temperature. The main electrical parameters such as concentration of donor atoms (N-D), diffusion potential (V-D), depletion layer thickness (W-D), Fermi energy level (E-F), barrier height (phi(B)), and maximum electric field (E-m) were extracted for each measured frequency. The phi(B), W-D, and E-F values are increasing with increased frequency, while N-D and E-m exponentially decrease. The surfacestates (N-SS) were evaluated using the low-high-frequency capacitance technique. Furthermore, the basic dielectric parameters such as tangent-loss (tan delta), electrical conductivity (sigma(ac)), real and imaginary parts of epsilon*, electric-modulus (M*), and complex impedance (Z*) were investigated. The obtained results indicate that the N-SS, and RuO2:PVC organic interlayer are more effective on C and G/omega measurements.
Frequency Response of Metal-Semiconductor Structures With Thin-Films Sapphire Interlayer by ALD Technique
(Ieee-Inst Electrical Electronics Engineers Inc, 2021) Tan, Serhat Orkun; Tascioglu, Ilke; Altindal, Semsettin
MIS-type Al/Al2O3/p-Si structures were fabricated to identify its admittance analysis through capacitance/conductance versus logarithmic frequency (C/G-V-f) data in the 1 kHz-5 MHz and +/- 3 V ranges at room temperature. Admittance measurements determine the surface states (N-ss) and these states occurred at M/S interlayer arise as a result of high capacitance and conductance values at low frequencies. This is also explained by adequacy of tracking ac signal by N-ss at lower frequencies. In consequence with N-ss presence, a peak turns up or becomes visible at the normalized parallel conductance versus logarithm of frequency [G(p)/omega - ln(f)] plot under various biases. In the energy range of (0.17 - E-v)-(0.67 - E-v), N-ss and their life/relaxation time (tau) values vary from 4.95 x 10(12) to 7.42 x 10(11) eV(-1).cm(-2) and from 7.85 x 10(-5) to 1.05 x 10(-6) s, respectively.
Frequency-Dependent Admittance Analysis of the Metal-Semiconductor Structure With an Interlayer of Zn-Doped Organic Polymer Nanocomposites
(Ieee-Inst Electrical Electronics Engineers Inc, 2018) Tecimer, Huseyin; Tan, Serhat Orkun; Altindal, Semsettin
The capacitance-voltage (C-V) and conductance-voltage (G/omega-V) data for Al/(0.07Zn-doped polyvinyl alcohol)/p-Si structure have been performed (at +/- 6-V biases) in a frequency interval of 1-400 kHz at room temperature. Utilizing form conductance method, N-ss values were specified from admittance measurements. The reason of higher C and G values obtained at lower frequencies was ascribed to the surface states located atMS interface and insulator layer. The increment at capacitance and conductance was occurred in consequence of the ac signal that followed easily by the surface states at these lower frequencies. The surface states existence also generates peaks at conductance versus logarithm of frequency (Gp/omega-log(f)) plots under distinct voltage values. The acquired values of Nss and relaxation time (tau) are in the interval of 1.94 x 10(14)-1.67 x 10(14) eV(-1).cm(-2) and 2.81 x 10(-3)-1.30 x 10(-5) s, respectively.
Identification of Current Transport Mechanisms and Temperature Sensing Qualifications for Al/(ZnS-PVA)/p-Si Structures at Low and Moderate Temperatures
(Ieee-Inst Electrical Electronics Engineers Inc, 2022) Alsac, Aysun Arslan; Serin, Tulay; Tan, Serhat Orkun; Altindal, Semsettin
Current transport mechanisms (CTMs) and temperature sensing qualifications of Al/(ZnS-PVA)/p-Si structures are identified with the help of temperature-dependent forward bias current-voltage measurements. To determine the current transport mechanism, the electrical parameters of the structure such as saturation current (I-o), zero - bias barrier height (Phi(B0)), ideality factor (n) are determined from these characteristics measured in the temperature range of 60-320 K. The temperature dependencies of the calculated Phi(Bo) and n values indicate the existence of double Gaussian distribution (DGD) of barrier height (BH) at M/S interface. Using the modified Richardson plots, Phi(B0) and A* values have been found in the high temperature region (HT) (160-320 K) as 0.95 eV, 31.64 A.cm(-2)K(-2), respectively and in the low temperature region (60-140 K) as 0.3871 eV, 20.996 A.cm(-2)K(-2), respectively. The A* value in the HT region is very close to its theoretical value and hence the CTMs can be explained by the DGD of BH. Sensitivity (S) values are calculated for each voltage at forward biases from the temperature-dependent variation of the logarithm of the
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.
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.
Overview of the irradiation-dependent behaviour of the negative dielectric properties of GaAs-based MIS devices
(Pergamon-Elsevier Science Ltd, 2024) Baydilli, Esra Evcin; Kaymaz, Ahmet; Altindal, Semsettin
In this study, negative dielectric properties of the natural oxide interfacial-layered metal-insulator-semiconductor (MIS) type structure have been investigated under different radiation doses. Some essential parameters of the GaAs-based MIS structure, such as dielectric constant (e '), dielectric loss (e) and loss factor (tan6), were obtained from the capacitance/conductance-voltage (C-G/w-V) data for before and after radiation to investigate the effects of gamma-rays on the dielectric properties of the device. Measurements were performed in the voltage range of +/- 4 V, 500 kHz frequency and at room temperature for before irradiation and after 5 and 10 kGy radiation doses to obtain C-G/w-V data under various conditions. On the other hand, the voltage-dependent variation of the ac-conductivity (aac) and complex electric modulus (M*) (including its real (M ') and the imaginary (M '') parts) of the structure were calculated before and after radiation. As a result, the peaks at approximately 1.75 V were observed in the voltage-dependent variation of the dielectric constant before irradiation and after all radiation doses. It was also observed from this point that the dielectric constant quickly took negative values, and these behaviours were attributed to the structure's differential change of charge, polarization, and electrical resonance. However, there was no significant change in the radiation-dependent dielectric properties of the structure up to the abnormal peak values. In conclusion, it can be said that although the device is generally resistant to ionizing radiation, it exhibits significant change behaviour in the negative dielectric region. This result means that when the device is operated under appropriate conditions, it can respond as a radiationresistant rectifier diode or electronic device that can benefit from its negative dielectric properties.
The photoresponse behavior of a Schottky structure with a transition metal oxide-doped organic polymer (RuO2:PVC) interface
(Springer, 2024) Elamen, Hasan; Badali, Yosef; Ulusoy, Murat; Azizian-Kalandaragh, Yashar; Altindal, Semsettin; Gueneser, Muhammet Tahir
The RuO2-doped organic polymer composite structure was used as the interface to study the photodiode properties of a Schottky structure. Some basic electrical and optoelectrical parameters of the structure interlaid with RuO2:PVC were investigated using the I-V characteristics in the dark and under definite illuminations. The values of saturation current (I-0), barrier height (phi(B0)) at zero-bias, ideality factor (n), series and shunt resistances (R-s and R-sh) were calculated by using different methods such as thermionic emission, Ohm's law, Cheung and Norde functions. They were found to be intensely depend on illumination levels and voltage. Forward bias I-V data were used to obtain energy-dependent profiles of interface-states (N-ss) for each illumination level. Moreover, the open-circuit voltage (V-oc), short circuit current (I-sc), filling factor (FF), and efficiency (eta) of the fabricated Schottky structure were found as 0.118 V, 6.4 mu A, 46%, and 0.088% under 50 mW/cm(-2), respectively. According to the findings, the RuO2:PVC organic interlayer is light-sensitive and can thus be used in optoelectronic applications, such as photodetectors and photodiodes.[Graphic]
The possible current-conduction mechanism in the Au/(CoSO4-PVP)/n-Si junctions
(Springer, 2020) Elamen, Hasan; Badali, Yosef; Guneser, Muhammet Tahir; Altindal, Semsettin
The possible current-conduction mechanism (CCMs) of the Au/CoSO4-PVP/n-Si junctions was investigated using temperature-dependence current-voltage (I-V) experiments over 100-360 K. The experimental results showed that the value of BH increases approximately linearly with increasing temperature. Such positive temperature coefficient (alpha = Delta phi(B0)/Delta T) is in agreement with the reported negative temperature coefficient of the bandgap of Si (= - 0.473 meV/K). The (n(ap)(-1)-1) vsq/2kT curves have different characters in two temperature ranges due to having separate two barrier distributions. The rho(2)and rho(3)values obtained from intercept and slope of these curves as 0.521 V and 0.011 V for 240-360 K temperature range and 0.737 V and 0.004 V for the 100-220 K range. This results show that the high temperature region with smaller rho(2)and larger rho(3)voltage deformation coefficients has a wider and greater of the barrier height distribution than the second region. As an evidence for the Gaussian distribution, the phi(B0)and standard deviation (sigma(0)) were derived from the intercept and slope of the phi(B0)-q/2kT curves as 1.14 eV and 0.163 V at high temperatures and 0.62 eV and 0.088 V at low temperatures. The Richardson constant obtained as 102 A/cm(2)K(2)for 240-360 K temperature range using standard deviation value which is similar to the theoretical Richardson constant value of silicon (112 A/cm(2)K(2)). For each temperature, the profile ofN(ss)vs (E-c-E-ss) was provided using the voltage-dependent effective barrier height (phi(e)) value. It was observed that these surface conditions decreased with increasing temperature.

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