Frequency and voltage dependence of electrical and dielectric properties in metal-interfacial layer-semiconductor (MIS) type structures

© 2020 Elsevier B.V.Zinc-ferrite nanostructures were fabricated using ultrasonic-assisted-method. FE-SEM, EDX and XRD were utilized for the investigation of morphological and structural properties. Au/(ZnFe2O4-PVP)/n-Si MPS structures were prepared for the purpose of characterizing electrical and dielectric properties via impedance-spectroscopy-method (ISM) between -2 V and 5 V in the frequency range of 10 kHz-5MHz. The frequency-dependent values of electrical parameters such as VD, ND, EF, WD and ΦC-V were extracted from the reverse bias C−2-V. Voltage-dependent profiles of Rs and Nss was calculated using Nicollian-Brews and high-low frequency capacitance (CLF-CHF) methods. Results showed Nss is more effective are depletion and inversion whereas accumulation region is the region at which Rs is more effective. The real and imaginary parts of ε* and M* were calculated and showed strong dependence on frequency and voltage. The higher values of C, G/ω or ϵ', ϵ" at low frequencies and observed peak in the M″-V and (tanδ)-V were associated with Nss

A comparison of electrical parameters of Au/n-Si and Au/(CoSO 4 –PVP)/n-Si structures (SBDs) to determine the effect of (CoSO 4 –PVP) organic interlayer at room temperature

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. In this study, the Au/n-Si structures with and without (CoSO 4 –PVP) organic interlayer were fabricated on the same n-Si wafer and electrical characteristics of them were analyzed by using current, capacitance, and conductance measurements in forward and reverse bias voltages and experimental results were compared with each other. The values of ideality factory (n), zero-bias barrier height (Φ Bo ), and the rectifying ratio (RR at ± 3 V) for Au/n-Si and Au/(CoSO 4 –PVP)/n-Si structures were found as 2.453, 0.732 eV, 2.01 × 10 3 and 2.489, 0.799, 5.37 × 10 4 by using the I–V measurements, respectively. The RR of Au/(CoSO 4 –PVP)/n-Si structures at ± 3 V was 26.77 times higher than Au/n-Si structure. The concentration of donor-atoms (N D ), Fermi energy (E F ) and barrier height for these two structures were found as 15.06 × 10 14 cm −3 , 0.254 eV, 0.744 eV and 2.310 × 10 14 cm −3 , 0.303 eV, 1.010 eV from the C −2 –V characteristics in the reverse bias region at 1 MHz in dark, respectively. These results show that the use of (CoSO 4 –PVP) polymer interface layer at Au/n-Si interface improves the performance of these structures. Additionally, a simple ultrasound-assisted method has been utilized to grown cobalt sulfide nanostructures. The morphological and structural analyses of them have been investigated by scanning electron-microscopy, and X-ray diffraction methods

A comparison study regarding Al/p-Si and Al/(carbon nanofiber–PVP)/p-Si diodes: current/impedance–voltage (I/Z–V) characteristics

© 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Al/p-Si and Al/(carbon nanofiber–PVP)/p-Si diodes were produced using a p-type silicon wafer with 10 Ω cm resistivity to determine the polymer interlayer effects on device characteristics. To assess whether carbon nanofiber–PVP interlayer is beneficial for electrical performance, the current–voltage (I–V) and the impedance–voltage (Z–V) measurements were performed in wide range of voltage. Thus, electrical parameters such as series resistance, barrier height, and ideality factor were derived from the forward bias Ln (IF)–VF and Cheung’s functions, so that they are compared and voltage dependence of them is explored. Later, the values of intercept voltage, width of depletion layer, doping acceptor atom concentration, and barrier height were also extracted from C−2–V data at 1 MHz and then results were compared with each other. The surface states and their energy profile were also extracted from the IF–VF characteristics by considering barrier height (BH) and n is voltage dependent as well. Experimental results indicate that the carbon nanofiber–PVP interlayer decreases surface states (Nss), series resistance (Rs) and leakage current, whereas it increases rectifying ratio and shunt resistance. Hence, such polymeric interlayer material forms an interesting alternative to conventional oxide layer due to some advantages of polymers such as desirably low values of cost, weight, and energy consumption

Investigation of the efficiencies of the (SnO2-PVA) interlayer in Au/n-Si (MS) SDs on electrical characteristics at room temperature by comparison

© 2019, Springer Science+Business Media, LLC, part of Springer Nature.Au/n-Si (MS) and Au/(SnO2-PVA)/n-Si (MPS) type SDs were manufactured at identical conditions for investigation of the (SnO2-PVA) organic/polymer interlayer effects on the electrical characteristics using voltage dependent current (I) and capacitance/conductance (C/G) data and compared each other. Rectifying ratio (RR) and the barrier height (BH) were found from forward bias ln(I)–V plots,. The values found are 2.5 × 102 and 0.57 eV for MS type SDs and 2 × 103 and 0.68 eV for MPS type SDs, respectively. The ideality factor (n), series resistance (Rs) and BH were also calculated from Cheung’s functions. They are agreement observed to be compatible with other results. The surface states versus (Ec−Ess) and Rs versus V curves were calculated by using the I–V data by using Roderick and Ohm’s law. The doping donor atoms (ND), Fermi energy (EF), BH of these SDs were also calculated from the reverse bias C−2–V data. While the calculated values of surface states and leakage current for the MPS is lower than Au/n-Si SD, RR is higher. Obtained results prove the use of a (SnO2-PVA) organic interlayer improved the performance of the Au/n-Si diodes

A comparison study regarding Al/p-Si and Al/(carbon nanofiber-PVP)/p-Si diodes: current/impedance-voltage (I/Z-V) characteristics

Al/p-Si and Al/(carbon nanofiber-PVP)/p-Si diodes were produced using a p-type silicon wafer with 10 omega cm resistivity to determine the polymer interlayer effects on device characteristics. To assess whether carbon nanofiber-PVP interlayer is beneficial for electrical performance, the current-voltage (I-V) and the impedance-voltage (Z-V) measurements were performed in wide range of voltage. Thus, electrical parameters such as series resistance, barrier height, and ideality factor were derived from the forward bias Ln (I-F)-V(F)and Cheung's functions, so that they are compared and voltage dependence of them is explored. Later, the values of intercept voltage, width of depletion layer, doping acceptor atom concentration, and barrier height were also extracted from C-2-Vdata at 1 MHz and then results were compared with each other. The surface states and their energy profile were also extracted from theI(F)-V(F)characteristics by considering barrier height (BH) and n is voltage dependent as well. Experimental results indicate that the carbon nanofiber-PVP interlayer decreases surface states (N-ss), series resistance (R-s) and leakage current, whereas it increases rectifying ratio and shunt resistance. Hence, such polymeric interlayer material forms an interesting alternative to conventional oxide layer due to some advantages of polymers such as desirably low values of cost, weight, and energy consumption.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).WOS:0005511003000012-s2.0-8508830623

Determining electrical and dielectric parameters of Al/ZnS-PVA/p-Si (MPS) structures in wide range of temperature and voltage

WOS: 000438679000024In this study zinc sulphide (ZnS) nanostructures have been prepared by microwave-assisted method in presence of polyvinyl alcohol (PVA) as a capping agent. The structural and morphological properties of prepared sample have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). These analyses confirm that the sample has nano structure. They have been used this sample to fabrication of Al/ZnS-PVA/p-Si structure. The effect of temperature and voltage on the electrical and dielectric parameters of the Al/ZnS-PVA/p-Si (MPS) structures has been investigated in the wide range of temperature (140-340 K) and voltage (- 2 V to + 4 V) using capacitance/conductance-voltage (C/G-V) measurements at 500 kHz. Experimental measurements revealed that the values of C/G-V increase with increasing temperature but the values of series resistance (R (s) ) increase with decreasing temperature. As well as the dielectric parameters such as the values of real and imaginary parts of the dielectric constants (epsilon' and epsilon aEuro(3)) and electric modules (M' and MaEuro(3)), loss tangent (tan delta), and ac electrical conductivity (sigma (ac) ) were obtained using C and G/omega data. These parameters are found out as strong functions of temperature and voltage. While the values of epsilon', epsilon aEuro(3) and tan delta increase with increasing temperature, the values of sigma (ac) , M' and MaEuro(3) decrease. The Arrhenius plot (ln(sigma(ac)) vs q/kT) shows two distinct linear ranges with different slopes or activation energies (E (a) ) at low (140-230 K) and high (260-340 K) temperatures. Both values of R (s) and (ZnS-PVA) interfacial layers are also very effective parameters on the electric and dielectric properties.Gazi University Scientific Research ProjectGazi University [GU-BAP.05/2018-10]This study was supported by Gazi University Scientific Research Project. (Project Number: GU-BAP.05/2018-10)

Frequency-Dependent Admittance Analysis of Au/n-Si Structure with CoSO4-PVP Interfacial Layer

A film of cobalt sulfate (CoSO4)-doped polyvinylpyrrolidone (PVP) blend was spin-coated on n-Si. Electrical measurements were conducted on the Au/n-Si structure with the CoSO4-PVP film sandwiched between them. The frequency dispersion of the main electrical and dielectric parameters and the corresponding mechanisms were evaluated. The extra capacitance originating from the contribution of interface states (N-ss) resulted in a fairly large frequency dispersion in C-V plots. These states also influence the carrier transport and conduction mechanism, thus the determination of real N-ss values is crucial to evaluate the nonideal behavior of such plots. The values of N-ss were calculated using the Hill-Coleman method. The dielectric constant (epsilon ') and dielectric loss (epsilon '') exhibited higher values in the low-frequency region as a result of interface and dipole polarization, while the alternating-current (AC) electrical conductivity (sigma(ac)) generally decreased. The variation of the loss tangent with increasing frequency of the applied field confirmed the effect of some internal field within the CoSO4-PVP film accompanied by the external AC field

Determining electrical and dielectric parameters of dependence as function of frequencies in Al/ZnS-PVA/p-Si (MPS) structures

WOS: 000394232600022We have studied electrical and dielectric parameters of the Al/ZnS-PVA/p-Si structures using admittance measurements. For this aim, capacitance/conductance-voltage (C/G-V) measurements were performed in the frequency range of 10 kHz-5 MHz and voltages (+/- 4 V) by 50 mV steps at 300 K. Experimental results confirmed that both electric and dielectric parameters are strong function of frequency and voltage and they are especially influenced from series resistance (R-s), surface states (N-ss) and polarization processes. The values of R-s and N-ss which are obtained from the Nicollian and Brews and Hill-Coleman method, respectively, and they are decrease with increasing frequency almost as exponentially. In addition, the values of real and imaginary part of the dielectric constants (epsilon' and epsilon '') and electric modules (M' and M ''), loss tangent (tan delta), and ac electrical conductivity (sigma(ac)) were obtained using C and G/omega data as function of applied bias voltage and they are found to a strong functions of frequency. While the values of epsilon', epsilon '', and tand increase with increasing frequency, M' and rac decrease. Moreover, the epsilon', epsilon '', tand, and rac increase with applied bias voltage, whereas the M' decreases with increasing applied bias voltage. The M '' versus V plot shows a peak and its position shifts to the right with increasing bias voltage and it disappears at high frequencies. As a result, the change in the epsilon', epsilon '', tan delta, M', M '' and rac is a result of restructuring and reordering of charges at the (ZnS-PVA)/p-Si interface under an external electric field or voltage and interface polarization

Temperature and Interfacial Layer Effects on the Electrical and Dielectric Properties of Al/(CdS-PVA)/p-Si (MPS) Structures

WOS: 000445474800031In the present study, cadmium sulphide (CdS) nanopowders were prepared by using a simple physical ball milling technique, and their x-ray diffraction (XRD) analysis confirmed the formation of hexagonal wurtzite structure of CdS. The morphology of CdS nanopowders was characterized by scanning electron microscope (SEM). Dielectric and electrical properties of the manufactured Al/(CdS-PVA)/p-Si (MPS) type structures were investigated by capacitance-voltage (C-V) and conductance-voltage (G/-V) measurements as functions of temperature and applied bias voltage at 500kHz. Some main parameters of the structure such as real and imaginary parts of complex dielectric constants, epsilon(=epsilon-j epsilon), loss tangent (tan), a.c. electrical conductivity (sigma(ac)), and real and imaginary parts of complex electric modulus, M*(=M+jM) of the structure were investigated in the temperature range between 230K and 340K. Ln(sigma(ac))-q/kT curve showed a linear behavior. The value of activation energy (E-a) was obtained as 0.0601eV at 5.0V from the slope of this curve. Moreover, argand diagrams of complex modulus were studied to determine relaxation process of these structures.Duzce University Scientific Research ProjectDuzce University [2017.07.02.567]; Gazi University Scientific Research ProjectGazi University [GU-BAP.05/2018-10]This study was financially supported by Duzce University Scientific Research Project (Project Number: 2017.07.02.567) and Gazi University Scientific Research Project (Project Number: GU-BAP.05/2018-10)