On the intersecting behaviour of experimental forward bias current-voltage (I-V) characteristics of Al/SiO2/p-Si (MIS) Schottky diodes at low temperatures

WOS: 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

Effects of gamma-ray irradiation on the C-V and G/omega-V characteristics of Al/SiO2/p-Si (MIS) structures

WOS: 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

Investigation 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

In 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).WOS:0005593755000092-s2.0-8508936624

The distribution of the barrier height in Al-TiW-Pd2Si/n-Si Schottky diodes from I-V-T measurements

WOS: 000254385900003The forward and reverse bias current-voltage ( I-V) characteristics of Al-TiW-Pd2Si/n-Si Schottky barrier diodes ( SBDs) were measured in the temperature range of 300-400 K. The estimated zero-bias barrier height Phi(B0) and the ideality factor n assuming thermionic emission ( TE) theory show a strong temperature dependence. While n decreases, Phi(B0) increases with increasing temperature. The Richardson plot is found to be linear in the temperature range measured, but the activation energy value of 0.378 eV and the Richardson constant ( A*) value of 15.51 A cm(-2) K-2 obtained in this plot are much lower than the known values. Such behavior is attributed to Schottky barrier inhomogeneities by assuming a Gaussian distribution of barrier heights ( BHs) due to BH inhomogeneities that prevail at the interface. Also, the Phi(B0) versus q/2kT plot was drawn to obtain evidence of a Gaussian distribution of the BHs, and Phi(B0) = 0.535 eV and sigma(0) = 0.069 V for the mean BH and zero-bias standard deviation, respectively, have been obtained from this plot. Thus, the modified ln(I-0/T-2) - q(2)sigma(0)(2)/2k(2)T(2) versus q/kT plot gives Phi(B0) and A* as 0.510 eV and 121.96 A cm(-2) K-2, respectively. This value of the Richardson constant 121.96 A cm(-2) K-2 is very close to the theoretical value of 120 A K-2 cm(-2) for n-type Si. Hence, it has been concluded that the temperature dependence of the forward I-V characteristics of the Al-TiW-Pd2Si/n-Si Schottky barrier diodes can be successfully explained on the basis of a thermionic emission mechanism with a Gaussian distribution of the BHs

Dielectric properties, electrical modulus and current transport mechanisms of Au/ZnO/n-Si structures

Au/ZnO/n-Si (MIS) structures were fabricated by using the RF sputtering method and their complex dielectric constant (epsilon{*}= epsilon'-j epsilon{''}), electric modulus (M{*}=M' + jM{''}) and electrical conductivity (sigma = sigma(dc) + sigma(ac)) values were investigated as a function of frequency (0.7 kHz-1 MHz) and voltage (- 6 - ( + 6 V)) by capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements to get more information on the conduction mechanisms and formation of barrier height between Au and n-Si. The In sigma-Inf plots have two different regions corresponding to low-intermediate and high frequencies. Such behavior of In sigma-Inf plots shows that the existence of two different conduction mechanisms (CMs) at low-intermediate and high frequencies. Moreover, the reverse bias saturation current (I-0), ideally factor (n), barrier height (Phi(B0)) were determined from the forward bias I-V data and they were found as a strong function of temperature. The value of n especially at low temperature is considerably higher than unity. The values of (Phi) over bar (B0) and standard deviation(sigma(s)) were found from the intercept and slope of (Phi) over bar (B0)-q/2kT plots as 0.551 eV and 0.075 V for the region I (80-220 K) and 1.126 eV and 0.053 V for the region II (220-400 K), respectively. The values of (Phi) over bar (B0) and effective Richardson constant (A{*}) were found from slope and intercept of activation energy plots as 0.564 eV and 101.084 Acm(-2) K-2 for the region I and 1.136 eV and 41.87 Acm(-2) K-2 for the region II, respectively. These results confirm that the current-voltage-temperature (I-VT) characteristics of the fabricated Au/ZnO/n-Si SBDs can satisfactorily be explained on the basis of TE theory with double GD of the BHs

Identifying of series resistance and interface states on rhenium/n-GaAs structures using C-V-T and G/omega-V-T characteristics in frequency ranged 50 kHz to 5 MHz (November, 10.1007/S10854-019-02578-1, 2019)

The original version of the article inadvertently published without the character omega ``omega{''} in all the places. This has been corrected by publishing this erratum. The original article has been corrected

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

Dielectric characterization of BSA doped-PANI interlayered metal-semiconductor structures

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