This study examines the radiation-dependent dielectric properties of an Au/(Co/Zn)-doped PVA/n-Si MPS-type Schottky structure (SS). Capacitance/conductance-voltage (C/(G/ω)−V) measurements were taken at 1 MHz frequency before and after 22 kGy radiation application on the 1st, 3rd, 5th, 10th, 20th, and 30th days. The dielectric constant (ε') and dielectric loss (ε”) parameters were calculated using the impedance/admittance spectroscopy method. The results indicate that the most significant difference occurred on the first day after irradiation. In the subsequent days, particularly on the 30th day, the values closely approached those of the unirradiated sample (U.S). Similar results were obtained for loss tangent (tan(δ)), ac-conductivity (σac), and the complex electric modulus (M*), including both the real (M') and imaginary (M”) parts. The results indicate that the sample is mainly affected by the transient effects of radiation, but there are also permanent radiation effects present. The results show that the polarisation mechanism, which is a crucial factor in dielectric properties, can be explained by the Maxwell–Wagner dispersion model based on Koop’s theory. The study concluded that the Au/(Co/Zn)-doped PVA/n-Si MPS-type SS can be safely and accurately used as a rectifier contact even after exposure to 22 kGy radiation.

In this study, the GaAs-based metal-semiconductor (MS) contact was prepared as a reference sample for comparison with other devices in the literature, especially some interfacial layered Schottky structures and temperature 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.

In this research, the dielectric characteristics of fabricated Al/(ZnFe 2 O 4 -PVA)/p-Si structures have been investigated in wide range frequency and voltage. Thus, by deriving capacitance-conductance (C-G/ω) measurements the main parameters of the metal-polymer-semiconductor (MPS) structure such as complex dielectric constants (ϵ′ and ϵ′′), loss tangent (tanδ), complex electric modulus (M′ and M′′) and ac electrical conductivity (σ 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.

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 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.

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 (tanδ), dielectric constant (ε′), dielectric loss (ε′′) 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 ε′, ε′′ and tanδ 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.

Electrical data of the Schottky structure with CdZnO interlayer have been evaluated for different illumination intensities. Considering such parameters as, the ideality factor ( n ), reverse saturation current ( I o ), zero bias barrier height (Φ Bo ), series and shunt resistances ( R s and R sh ) and surface states ( N s s ), we concluded that these parameters extremely depend on the illumination power and applied bias voltage. In consequence of the Ohm’s law and Norde’s method used for R s determination, the R s values decreased with increasing illumination intensity. The energy distribution of the N ss and voltage dependent profile of resistance ( R i ) of the structure were extracted from the forward bias current-voltage ( I-V ) data. The fabricated CdZnO interlayered metal-semiconductor structure appears to have photodiode behavior. Accordingly, the alteration in the basic electrical parameters by the increment in illumination levels indicates that, the carrier generation takes place in the depletion layer and the conductivity of the CdZnO interlayered structure is improved.

Determining the radiation effects on the basic electrical parameters of the fabricated high-dielectric MFIS structures, they were exposed to the high-energy 60Co γ-rays. For this purpose, the values of ideality factor (n), barrier height (ΦB) and series resistance (Rs) were extracted from the forward bias I–V data before and after irradiation by using various methods such as standard thermionic emission (TE) theory, Cheung’s and Norde functions. Additionally, the energy-dependent profile of surface states Nss was extracted by considering voltage dependence of n, ΦB and Rs and compared each other. Experimental results show that the reverse saturation current (Io), n and Rs values increase with increasing radiation dose, but ΦB decreases. When the value of Rs is considered in the calculation of Nss, they were found to be considerably decreased. The observed low discrepancies between Nss after irradiation show that the use of a high-dielectric ferroelectric interlayer leads to an increase in the resistance of MS to radiation. It is more important to fabricate radiation-resisted electronic device, especially in the satellites due to hard radiation in space. As a result, Nss, Rs and the existence of interlayer are more effectual on the I–V characteristics which must be considered in the electrical parameter calculation.

Au/PVA/n-GaAs (MPS) type Schottky diodes (SDs) were fabricated and investigated in a temperature range of 80–360 K to explain their possible conduction mechanisms (CMs). Three distinct linear regions with different slopes were observed in ln( I )– V plots. The first region (R1), is within the range of 0.22–0.60 V, the second region (R2), is within the range of 0.64–0.90 V, and the third region (R3), is within the range of 1.1–1.5 V. It was shown that both ideality factor ( n ) and zero-bias barrier height (Φ Bo ) are strong functions of temperature for all three regions. It was noticed that n values decreased and Φ Bo values increased with increasing temperature. In order to ascertain the possible CMs, Φ Bo − n , − Φ Bo − q /2 kT , and ( n −1 − 1) − q /2 kT plots were also examined. In each of these plots, two linear regions were obtained within each of the three regions. The region from 80–180 K is called the low-temperature range (LTR), and the region from 200–360 K is called the high-temperature range (HTR). It has been revealed that the reason for the deviation from the classical thermionic emission (TE) theory cannot be explained only by the existence of the interface layer, interface states ( N SS ) or quantum mechanical tunneling mechanisms, which can be also explained by the double Gaussian distribution (DGD) due to barrier inhomogeneity. Finally, the experimental Richardson constants ( A *) were calculated from the interception point of the modified Richardson curve in LTR and HTR for all three regions. It was calculated as 6.22 and 8.13 A/cm 2 K 2 for RI, 7.77 and 8.14 A/cm 2 K 2 at R2, and 7.07 and 8.13 A/cm 2 K 2 at R3 for low- and high-temperature ranges, respectively. It is clear that especially HTR results are quite close to the known theoretical A * value of 8.16 A/cm 2 K 2 for n-GaAs.

The possible current-transport mechanisms (CTMs) of Au/(%7Gr-doped)PVA/n-GaAs structure was examined between 80 K and 360 K. The forward bias semi-logarithmic I-V curves have two different linear regions; as 0.30 V and 0.56 V (Region I), and 0.72 V and 0.92 V (Region II). Contrary to classical thermionic emission (TE) theory, the ideality factor (n) decreases but the zero bias barrier height (Phi(Bo)) increases while the temperature increases for both regions. The plots of n vs Phi(B0), q/2 kT vs Phi(Bo) and q/2 kT vs n(-1)-1 have two linear regions from 80 K to 160 K and 180 K-360 K. This indicates the Double Gaussian Distribution (DGD). Experimental Richardson constant (A*) was acquired as 8.73 A/cm(2)K(2) and 8.14 A/cm(2)K(2) for Region I and II which are quite close to theoretical A* value for n-GaAs. Consequently, the predominant CTMs at M/S interfaces can be clarified by DGD on the basis of TE.

There are several methods used to obtain the basic diode parameters that affect the diode quality of Schottky diodes (SD) such as ideality factor (n), barrier height (ΦBo), and series resistance (Rs). In this study, it is aimed to compare the results using Ohm’s law, Thermionic Emission theory (TE), Norde and Cheung-Cheung functions. The I–V measurement of the Au/7%Gr-doped PVA/n-GaAs type SD was taken in the range of 80–360 K in 20 K steps. Considering that each method is effective in the different voltage region of the I–V curve and the parameters are strongly voltage-dependent, the results are compatible with each other. Also, the interface states (Nss) were calculated with and without Rs for each temperature value, and it was attained that the effect of Rs reduced Nss values by almost 1 degree. This result reveals the importance of the Rs parameter for SDs. As a result, it is plainly represented that the basic diode parameters n, Rs and ΦBo values are strongly dependent on temperature and voltage, and affected by barrier inhomogeneity and surface states.

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 (NA), depletion layer width (WD), series resistance (Rs), barrier height (ΦB), and surface states/traps (Nss/Nit)) 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 Nss are more effective in the depletion layer. On the other hand, voltage-dependent profiles of Rs and Nss 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 Rs. These calculations show that Rs 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.

The measured capacitance and conductance–voltage (C&G/ω–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 (ε* = ε′ − jε″), loss tangent (tanδ), complex electric modulus (M* = M′ + jM″), and electrical conductivity (σ). It was uncovered that dielectric constant (ε′), dielectric loss (ε″), tanδ, 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 (Nss) and the BSA doped-PANI interlayer. Such behavior in ε′, ε″, and tanδ, behavior with frequency was also explained by Maxwell–Wagner relaxation. The values of σ 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.

Bu çalışmada, 50 ve 150 nm kalınlıklarına sahip (Zn-katkılı PVA) polimer ara yüzey tabakalı Al/p-Si (MPS) yapıların elektriksel özellikleri, kapasitans-kondüktans-voltaj (C-G/w-V) ölçüm metodu kullanılarak frekansa bağlı incelendi. C-G/w-V ölçümleri -3.5/+5.5 V aralığında 50 mV adımlarla 2kHz, 20kHz ve 200kHz frekanslarında oda sıcaklığında alındı. Ters öngerilim C-2-V grafiklerinin lineer kısmının kesim noktası ve eğimlerinden faydalanılarak; difüzyon potansiyeli (VD,) alıcı katkı atomlarının yoğunluğu (NA), Fermi enerji (EF) seviyesi, tüketim tabakasının kalınlığı (WD) ve potansiyel engel yüksekliği (FB) gibi temel elektriksel parametreler hem frekansa hem de kalınlığa bağlı olarak elde edilerek karşılaştırıldı. Bu parametrelerin tümü oldukça hem organik arayüzey tabakasının kalınlığına hem de frekansa bağlı değişiklik göstermektedir. Ayrıca Nicollian ve Brews metodu kullanılarak bu yapıların direnci (Ri) ve düşük-yüksek frekans (CLF-CHF) kapasitans metodu kullanılarak da arayüzey durumlarının (Nss) voltaja bağlı değişim profilleri elde edildi. Seri direnç (Rs) etkisinin hangi bölge ve frekansta daha etkin olduğunu belirlemek için yapıların ölçülen C-G/w-V eğrileri Rs değeri dikkate alınarak düzeltildi. Elde edilen deneysel sonuçlar hem polimer arayüzey tabaka kalınlığının hem de Rs ve Nss değerlerinin C-G/w-V ölçümleri üzerinde oldukça etkili olduğu gözlendi.

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 (ΦBo), series resistance (Rs) and the voltage dependence resistance (Ri) 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 105 and 107, 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.

The frequency effect on the dielectric features of Zn doped polymer interlayered metal–semiconductor (MS) structure has been investigated by admittance measuring methods. As a function of frequency and voltage, the parameters such as dielectric constant (ε′), dielectric loss (ε″), dielectric loss tangent (tanδ), and ac electrical conductivity (σac) have been calculated. The values of ε′, ε″ and tanδ were decreased with frequency increment for each applied bias. The decrement at ε′ and ε″ by frequency increase indicated that the interfacial dipoles have not enough time to orient themselves in the alternate field direction. While the M′ value increase with frequency and reach a maximum, M″ displays a peak where its position shifts to higher frequency with increasing applied bias. The ln(σac) vs ln(ω) plot of the structure at 6 V has two linear regions with different slopes. Such behavior of ln(σac) vs ln(ω) plot reveals that there are two distinct conduction mechanisms in the Al/(0.07Zn-doped PVA)/p-Si MPS type SBDs at room temperature.

In this study, the current–voltage characteristics of non-doped and distinct graphene (Gr)-doped polyvinyl alcohol (PVA) interlayers in metal/organic polymer semiconductor type Schottky junction structures (SJSs) were investigated on both forward and reverse biases under distinct levels of illumination. The distinct doping concentration ratios (1%, 3% and 7%) of the Gr added to the PVA interlayers were compared by taking into account the basic electrical parameters, such as saturation current ( I o ), ideality factor ( n ), barrier height (Φ Bo ), series ( R s ) and shunt resistance ( R sh ). The 7% Gr-doped structure displayed the lowest I o values at zero bias. Moreover, the results indicated that the 7% Gr-doped PVA decreased the n value but increased the Φ Bo value compared with values associated with structures that have different doping concentrations. In terms of quality and reliability, the R s and R sh values of the SJSs were obtained using Ohm’s law and Cheung’s functions, and the 7% Gr-doped structure eventually displayed more uniformly distributed and lower R s values and the highest R sh values. Consequently, the 7% Gr-doped structure had better overall quality because of its superior electrical properties compared with structures that have other doping concentrations. Therefore, the 7% Gr-doped structure can be used as a photodiode in electronic devices.

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.

Photovoltaic effects were tracked on both electric and dielectric properties of Au/(Ni, Zn)-doped polyvinyl alcohol/n-Si Schottky barrier diodes as function of illumination intensity by 50 W steps at 1 MHz and in the voltage interval of (− 4)–(+ 5) V. The measurements indicate that ac electrical conductivity (σ ac ), dielectric constant’s both real and imaginary parts (ε′, ε″), loss tangent (tanδ) and electric modulus (M′, M″) are highly relevant functions of illumination and voltage. The variations in depletion region can be ascribed to the charges at interface and its reordering and restructuring under illumination and electric field but then accumulation region variations can be ascribed to the interfacial layer and series resistance (R s ). The values of εʹʹ and tanδ show a step increase with the increasing voltage for each illumination intensity while the values of ε′ show an anomalous peak (~ 1.4 V). C–V plot shows an intersection behavior at about 2.2 V due to lack of enough free charges in low illumination. The values of σ ac increase with increasing illumination and voltage due to the formation electron–hole pairs. The M″ vs V have two peaks for each illumination intensity and peak value increases with increasing illumination intensity and its positions tend to shift towards low voltage region.

Au/ZnO/n-GaAs Schottky barrier diodes (SBDs) have been examined by the capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements. The frequency dependence characteristics of measurements were obtained under various illumination levels at room temperature. The C and G/ω relation was observed as the decrement in capacitance corresponds to an increment in conductance. The increment of negative capacitance (NC) values by high frequency at forward biases was ascribed to the series resistance, interface states and interfacial layer. Considering the illumination intensity, the NC values were observed to increase with the decreasing illumination while the G/ω values increase with the increasing illumination. This behavior was referred to the increments in the polarization and carriers in the SBDs. The adverse impacts of the voltage dependent resistivity were decreased with increasing illumination levels. Eventually, a strong interaction between the electrical properties of SBDs and the frequency, illumination and applied bias voltage was demonstrated by experimental results.