61 research outputs found
Dielectric characterization of BSA doped-PANI interlayered metal-semiconductor structures
No full textThe 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
THE INVESTIGETION OF FREQUENCY AND TEMPERATURE DEPENDENCE OF ELECTRICAL AND DIELECTRIC PROPERTIES OF Au/SiO2/n-GaAs (MOS) STRUCTURES
No full textu/SiO2/n-GaAs (MOS) yapıların; seri direnç (Rs), arayüzey durumları (Nss) ve
ac elektrik iletkenlik (sac) gibi elektriksel karakteristikleri ile dielektrik sabiti
(e\'), dielektrik kayıp (e\"), dielektrik kayıp tanjantı (tand), reel ve imajiner
elektrik modülü (M\' and M\") gibi dielektrik özelliklerinin frekans, sıcaklık ve
oksit tabaka kalınlığına bağımlılığı, 80-350 K sıcaklık aralığında değisik frekans
ve oksit tabaka kalınlıkları için deneysel kapasitans-voltaj (C-V) ve
kondüktans-voltaj (G/w-V) ölçümleri kullanılarak arastırıldı. Deneysel sonuçlar
göstermistir ki; özellikle yüksek sıcaklık ve düsük frekanslarda, arayüzey
durum yoğunluğunun (Nss) dağılımı ile gevseme zamanı t ve arayüzeyin termal
olarak yeniden yapılanmasına bağlı olarak C ve G/w değerleri frekans, sıcaklık
ve oksit tabaka kalınlığına oldukça bağımlıdır. Au/SiO2/n-GaAs (MOS)
yapısının Rs ve Nss değerleri sırasıyla Nicollian ve Hill-Coleman metotları
kullanılarak hesaplanmıs olup bu değerler artan frekansla azalmaktadır. Artan
sıcaklıkla azalan seri direnç, artan oksit kalınlığına bağlı olarak lineer olarak
artmaktadır. Dielektrik sabiti, dielektrik kayıp, kayıp tanjant ve elektrik
modülünün frekans, sıcaklık ve oksit tabaka kalınlığının kuvvetli bir fonksiyonu
olduğu bulundu. ε\', ε\'\' ve tanδ değerleri artan frekansla azalırken reel ve
imajiner elektrik modülü artan frekansla artmaktadır. Ayrıca, ε\' ve ε\'\' artan
v
sıcaklıkla artarken, reel ve imajiner elektrik modülü artan sıcaklıkla
azalmaktadır. Artan oksit kalınlığına bağlı olarak dielektrik sabiti e\' değerleri
azalırken, tand ve elektrik modülünün imajiner bileseni olan M\" değerleri
artmaktadır.The frequency, temperature and oxide thickness dependence of electrical
characteristics such as series resistance (Rs), interface states (Nss) and ac
electrical conductivity (sac) and dielectric properties such as dielectric constant
(e\'), dielectric loss (e\"), dielectric loss tangent (tand), real and imaginary part of
electric modulus (M\' and M\") of the Au/SiO2/n-GaAs (MOS) structures have
been investigated in the temperature range of 80-350 K at various frequencies
by using experimental capacitance-voltage (C-V) and conductance-voltage (G/w-
V) measurements. Experimental results show that both the values of C and G/w
were quite sensitive to frequency, temperature and oxide layer thickness at
relatively high temperatures and low frequencies due to a continuous density
distribution of Nss and their relaxation time (t), and thermal restructuring and
reordering of the interface. The values Rs and Nss of the Au/SiO2/n-GaAs (MOS)
structure were obtained from Nicollian and Hill-Coleman methods, respectively,
and their values decrease with increasing frequency. While the series resistance
decreases with increasing temperature, it increases linearly with increasing
oxide layer thickness. The dielectric constant, dielectric loss, loss tangent and
the electric modulus were found a strong function of frequency, temperature
and oxide layer thickness. While the values of the ε\', ε\'\' and tanδ decrease with
increasing frequencies, the electric modulus (real and imaginary part) increase
vii
with increasing frequency. Also, while the dielectric constant and dielectric loss
increase with increasing temperature, electric modulus (real and imaginary
part) decrease with increasing temperature. While the ε\' decreases with
increasing oxide layer thickness tand and imaginary electric modulus increase
with increasing oxide layer thickness
The effect of different rates of ultra-thin gossamer-like rGO coatings on photocatalytic performance in ZnO core-shell structures for optoelectronic applications
No full textSakarya University of Applied Sciences Scientific Research Projects; [069-2022]Acknowledgements The study was funded by Sakarya University of Applied Sciences Scientific Research Projects (Project Number: 069-2022) .In the study, core-shell-structured Al/(ZnO:rGO)/pSi/Al photo-diodes were successfully fabricated using a sol-gel spin-coating method by varying the concentration of reduced-graphene oxide (rGO) from 1 % to 9 % (wt). The ZnO:rGO composite solution was coated on a silicon (p-Si) wafer at 1000 rpm and 300 K. Both aluminum back-ohmic and front-rectifier contacts were performed on the p-Si wafer by physical-vapor-deposition (PVD). The morphological and chemical structure of the photo-diodes were determined by using field-emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). The current -voltage (I-V) analysis in dark and under ultraviolet (UV, 365 nm) wavelength was utilized in detail. Basic electrical parameters, including the ideality factor (n), barrier height (BH) and series-shunt resistances (Rs, Rsh), were calculated using a variety of methods and compared to each other. The Card-Rhoderick method was used to extract energy-dependent profiles of interface traps (Nss). The core-shell-structured (ZnO-7 % rGO) photo-diode exhibited the best photocatalytic performance both in dark and under various illumination intensities (50-250 mW/cm2). The ZnO:rGO interlayer at the metal-semiconductor (M/S) interface leads to improvement of the photo-diode in respect of low-ideality factor/Nss/leakage-current and high-rectification and BH
Comparative Analysis of Temperature-Dependent Electrical and Dielectric Properties of an Schottky Device at Two Frequencies
No full textOn the intersecting behaviour of experimental forward bias current-voltage (I-V) characteristics of Al/SiO2/p-Si (MIS) Schottky diodes at low temperatures
No full textWOS: 000240123100013In this study, we have investigated the intersection behaviour of forward and reverse bias current-voltage (I-V) characteristics of Al/SiO2/p-Si Schottky diodes in the temperature range of 79-325 K. The crossing of the experimental semi-logarithmic ln(I)-V curves appears as an abnormality when seen with respect to the conventional behaviour of ideal Schottky diodes. Experimental results show that this crossing of ln(I)-V curves is an inherent property of even Schottky diodes. The ideality factor n was found to decrease, while the zero-bias Schottky barrier height (SBH) Phi(B0) increases with increasing temperature. The conventional Richardson plot is found to be nonlinear in the temperature range measured. However, the ln(I-0/T-2) versus 1000/nT plot gives a straight line corresponding to activation energy 0.233 eV. It is shown that the values of series resistance R-S estimated from Cheung's method were strongly temperature dependent and abnormally increased with increasing temperature. In addition, the temperature dependence of energy distribution of interface states density N-SS profiles was obtained from the forward bias I-V measurements by taking into account the bias dependence of the effective barrier height Phi(e) and ideality factor n. All these behaviours indicate that the thermionic emission (TE) cannot be the main current transport mechanism, especially at low temperatures
Controlling the electrical characteristics of Au/n-Si structure with and without (biphenyl-CoPc) and (OHSubs-ZnPc) interfacial layers at room temperature
No full textIn order to interpret well whether or not the organic or polymer interfacial layer is effective on performance of the conventional Au/n-Si (metal semiconductor [MS]) type Schottky barrier diodes (SBDs), in respect to ideality factor (n), leakage current, rectifying rate (RR), series and shunt resistances (R-s, R-sh) and surface states (N-ss) at room temperature, both Au/biphenyl-CoPc/n-Si (MPS1) and Au/OHSubs-ZnPc/n-Si (MPS2) type SBDs were fabricated. The electrical characteristics of these devices have been investigated and compared by using forward and reverse bias current-voltage (I-V) characteristics in the voltage range of (-4V)-(4V) for with and without (biphenyl-CoPc) and (OHSubs-ZnPc) interfacial layers at room temperature. The main electrical parameters of these diodes such as reverse saturation current (I-0), ideality factor (n), zero-bias barrier height (phi(B0)), RR, R-s and R-sh were found as 1.14x10(-5)A, 5.8, 0.6eV, 362, 44 and 15.9k for reference sample (MS), 7.05x10(-10)A, 3.8, 0.84eV, 2360, 115 and 270k for MPS1 and 2.16x10(-7)A, 4.8, 0.7eV, 3903, 62 and 242k for MPS2, respectively. It is clear that all of these parameters considerably change by using an organic interfacial layer. The energy density distribution profile of N-ss was found for each sample by taking into account the voltage dependence of effective barrier height (phi(e)) and ideality factor, and they were compared. Experimental results confirmed that the use of biphenyl-CoPc and OHSubs-ZnPc interfacial layer has led to an important increase in the performance of the conventional of MS type SBD. Copyright (c) 2015 John Wiley & Sons, Ltd
Dielectric Properties of Au/PVA (Cobalt-Doped)/n-Si Photoconductive Diodes
No full textGokcen, Muharrem/0000-0001-9063-3028;WOS: 000312660100014The voltage (V) and frequency (f) dependence of dielectric parameters such as the dielectric constant (epsilon'), dielectric loss (epsilon aEuro(3)), dielectric loss tangent (tan delta), real and imaginary parts of electrical modulus (M' and MaEuro(3)), and alternating-current (AC) electrical conductivity (sigma (AC)) of Au/PVA (cobalt-doped)/n-Si structures have been investigated by using experimental admittance measurements conducted at room temperature. The values of epsilon', epsilon aEuro(3), and tan delta were found to be strong functions of voltage and frequency, especially at low frequencies in the positive voltage region. It was observed that the values of epsilon' and epsilon aEuro(3) increase as the frequency decreases. The M' values increase with increasing frequency due to increasing dielectric relaxation, while MaEuro(3) values, in general, remain stable as frequency is changed. The sigma (AC) values at each bias voltage increase with increasing frequency.Duzce University Scientific Research ProjectDuzce University [2012.05.02.110]This work is supported by Duzce University Scientific Research Project (project no. 2012.05.02.110). Also, the author would like to thank Dr. Ibrahim Uslu (Department of Chemistry Education, Gazi University, Turkey), Dr. Tuncay Tunc (Department of Science Education, Aksaray University, Turkey), and Dr. Semsettin Altindal (Department of Physics, Gazi University, Turkey) for providing the material and its spinning
Frequency-Dependent Admittance Analysis of the Metal–Semiconductor Structure With an Interlayer of Zn-Doped Organic Polymer Nanocomposites
No full textInvestigation of effects on dielectric properties of different doping concentrations of Au/Gr-PVA/p-Si structures at 0.1 and 1 MHz at room temperature
No full textIn order to improve and detailedly investigate the dielectric properties of polymer interfaces of Metal-Polymer-Semiconductor (MPS) structures, three types of MPS were fabricated by doping 1, 3 and 5% graphene (Gr) into the polyvinyl alcohol (PVA) interface material. Capacitance-Voltage (C-V) and Conductance-Voltage (G/omega-V) measurements were used to analyze the dielectric properties of three types of MPS. UsingC-Vand G/omega-V data, series resistance (R-s) affecting device performance and interface properties besides basic dielectric parameters of each structure such as both the real and imaginary components of complex dielectric constant (epsilon'and epsilon''), complex electrical modulus (M' and M''), loss tangent (tan delta), and ac electrical conductivity (sigma(ac)) were also calculated. The effect of graphene doping was examined for each parameter and obtained results were compared at both low (0.1 MHz) and high (1 MHz) frequencies. It was observed that epsilon and epsilon'' decreased with increasing graphene doping at both 0.1 and 1 MHz, while M' and M'' increased under same conditions. Moreover, both the M' and M'' vs V plots have two distinctive peaks between -2.0 V and 0.0 V due to a special density distribution of surface states between (Gr-PVA) and p-Si. The tan delta gradually increased with increasing graphene doping at only 0.1 MHz. As the doping ratio of graphene increases, the charge carriers in the structure generate more dipoles and create an earlier relaxation process. In other words, increasing the doping ratio helps to improve the series resistance effects in MPS structures. As a result, it was seen that the interfacial properties of MPS structures were improved by increasing the rate of graphene doping.Gazi University Scientific Research Center [GU-BAP.05/2019-26]All authors would like to thank Gazi University Scientific Research Center for the supports and contributions (Project No: GU-BAP.05/2019-26)
Effects of gamma-ray irradiation on the C-V and G/omega-V characteristics of Al/SiO2/p-Si (MIS) structures
No full textWOS: 000255318700014The effect of the C-60(o) (gamma-ray) exposure oil the electrical characteristics of Al/SiO2/p-Si (MIS) structures has been investigated using capacitance-voltage (C - V) and conductance-voltage (G/omega - V) measurements. The MIS structures were stressed with a bias of 0 V during C-60(o) gamma-sources irradiation with the total dose range from 0 to 25 kGy. The C - V and G/omega - V characteristics were measured at 500 kHz and room temperature before and after C-60(o) gamma-ray irradiation. The results indicated that gamma-irradiation caused an increase in the barrier height Phi(B), interface states N-SS and depletion layer width W-D obtained from reverse bias C - V measurements. The series resistance R-S profile for various radiation closes was obtained from forward and reverse bias C - V and G/omega - V measurements. Both C - V and G/omega - V characteristics indicate that the total dose radiation hardness of MIS structures may be limited by the decisive properties of the SiO2/Si interface to radiation-induced damage. After gamma-irradiation, the decrease in capacitance of MIS structure results in the increase in the semiconductor depletion width. (c) 2008 Elsevier B.V. All rights reserved
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