Frequency, voltage and illumination interaction with the electrical characteristics of the CdZnO interlayered Schottky structure

Taşçıoğlu, İlke (Arel Author)cadmium-zincoxide (CdZnO) interlayered metal-semiconductor structure was examined by capacitance and conductance versus voltage data in dark and under 250W illumination at 100kHz, 500kHz and 1MHz frequencies, respectively. The effectuality of the frequency, applied voltage, illumination, and series resistance on the electrical parameters was discussed in detail. The increase in the frequency led to the decrement in capacitance and conductance and the increment in the illumination generally led to the increment in capacitance and conductance. An abnormal behavior was detected in the accumulation region of the C-V plots at 500kHz and 1MHz due to the inductive phenomenon of device. The effect of illumination intensity reduces the R-i values in the inversion region while enhances them in the depletion and accumulation region for 1MHz. Additionally, the series resistance values decrease with increasing frequency due to the specific dispersion of localized interface states. As a consequence of the experimental results, a remarkable interaction was realized between the electrical parameters and the illumination, frequency and applied biases

Illumination effect on admittance measurements of polyvinyl alcohol (Co, Zn-doped)/n-Si Schottky barrier diodes in wide frequency and applied bias voltage range

Istanbul Kultur University;Gebze Institute of Technology;Doga Nanobiotech Inc.;Terra Lab. Inc;LOT Oriel Group Europe1st International Congress on Advances in Applied Physics and Materials Science, APMAS2011 -- 12 May 2011 through 15 May 2011 -- Antalya --In order to have a good interpretation of the illumination effect on the capacitance-voltage (C-V) and conductance-voltage (G/?-V) profiles, C-V and G/?-V characteristics of the polyvinyl alcohol (Co, Zn-Doped)/n-Si Schottky barrier diodes (SBDs) were investigated in the wide frequency and applied bias voltage ranges at room temperature. Experimental results show that the values of both C and G/? are strong functions of frequency and applied bias voltage in dark and under illumination (200 W) conditions. It is clear that the dispersion in C and G/? is considerably high in the depletion and accumulation regions due to illumination induced electron-hole pairs and series resistance (R s) effect, respectively. The values of C and G/? exponentially decrease with the increasing frequency and at high frequencies (f>100kHz) the values of C and G/? become almost independent of frequency both in dark under illumination. © 2011 American Institute of Physics

Controlling the electrical characteristics of Al/p-Si structures through Bi4Ti3O12 interfacial layer

YILDIRIM, Mert/0000-0002-8526-1802WOS: 000324099300014In this study, the effects of high permittivity interfacial Bi4Ti3O12 (BTO) layer deposition on the main electrical parameters; such as barrier height, series resistance, rectifying ratio, interface states and shunt resistance, of Al/p-Si structures are investigated using the currentevoltage (I-V) and admittance measurements (capacitance-voltage, C-V and conductance-voltage, G/omega-V) at 1 MHz and room temperature. I-V characteristics revealed that, due to BTO layer deposition, series resistance values that were calculated by both Ohm's law and Cheung's method decreased whereas shunt resistance values increased. Therefore, leakage current value decreased significantly by almost 35 times as a result of high permittivity interfacial BTO layer. Moreover, rectifying ratio was improved through BTO interfacial layer deposition. I-V data indicated that high permittivity interfacial BTO layer also led to an increase in barrier height. Same result was also obtained through C-V data. Obtained results showed that the performance of the device is considerably dependent on high permittivity BTO interfacial layer. (C) 2013 Elsevier B.V. All rights reserved

Analysis of surface states and series resistance in Au/n-Si Schottky diodes with insulator layer using current-voltage and admittance-voltage characteristics

Tataroglu, Adem/0000-0003-2074-574XWOS: 000272057200001In order to good interpret the experimentally observed Au/n-Si (metal-semiconductor) Schottky diodes with thin insulator layer (18 angstrom) parameters such as the zero-bias barrier height (Phi(bo)), ideality factor (n), series resistance (R-s) and surface states have been investigated using current-voltage (I-V), capacitance-frequency (C-f) and conductance-frequency (G-f) techniques. The forward and reverse bias I-V characteristics of Au/n-Si (MS) Schottky diode were measured at room temperature. In addition, C-f and G-f characteristics were measured in the frequency range of 1 kHz-1 MHz. The higher values of C and G at low frequencies were attributed to the insulator layer and surface states. Under intermediate forward bias, the semi-logarithmic Ln (I)-V plot shows a good linear region. From this region, the slope and the intercept of this plot on the current axis allow to determine the ideality factor (n). the zero-barrier height (Phi(bo)) and the saturation current (I-s) evaluated to 2.878, 0.652 and 3.61 x 10(-7) A, respectively. The diode shows non-ideal I-V behavior with ideality factor greater than unity. This behavior can be attributed to the interfacial insulator layer, the surface states, series resistance and the formation barrier inhomogeneity at metal-semiconductor interface. From the C-f and G-f characteristics, the energy distribution of surface states (N-ss) and their relaxation time (tau) have been determined in the energy range of (E-c-0.493E(v))-(E-c-0.610) eV taking into account the forward bias I-V data. The values of N-ss and tau change from 9.35 x 10(13) eV(-1) cm(-2) to 2.73 x 10(13) eV(-1) cm(-2) and 1.75 x 10(-5) s to 4.50 x 10(-4) s, respectively. (C) 2009 Elsevier Ltd. All rights reserved.Gazi University Scientific Research Project (BAB)Gazi University [FEF 05/2009-34, FEF 05/ 2009-56]This work is supported by Gazi University Scientific Research Project (BAB), FEF-Research Project FEF 05/2009-34 and FEF 05/ 2009-56

Investigation of photovoltaic effect on electric and dielectric properties of Au/n-Si Schottky barrier diodes with nickel (Ni)-zinc (Zn) doped organic interface layer

WOS: 000424338500029Photovoltaic 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 (sigma (ac) ), dielectric constant's both real and imaginary parts (epsilon', epsilon aEuro(3)), loss tangent (tan delta) and electric modulus (M', MaEuro(3)) 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 epsilon(EE1)-E-1 and tan delta show a step increase with the increasing voltage for each illumination intensity while the values of epsilon' show an anomalous peak (similar to 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 sigma (ac) increase with increasing illumination and voltage due to the formation electron-hole pairs. The MaEuro(3) 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

Preparation and dielectric properties of polyvinyl alcohol (Co, Zn Acetate) Fiber/n-Si and polyvinyl alcohol (Ni, Zn Acetate)/n-Si Schottky diodes

WOS: 000296170400007Dielectric properties and ac electrical conductivity (sigma(ac)) of Au/PVA(Co, Zn acetate)/n-Si and Au/PVA(Ni, Zn acetate)/n-Si Schottky diodes (SDs) have been investigated in dark and under illumination by using experimental capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements at 1 MHz and room temperature. Experimental results indicate that the change in dielectric constant (e), dielectric loss (epsilon ''), loss tangent (tan delta), the real (M') and imaginary (M '') parts of electric modulus and ac electrical conductivity (sigma(ac)) with illumination were found to change linearly with illumination level (P). On the other hand, the epsilon', epsilon '', tan delta and sigma(ac) vs P have positive slope while the M' and M '' vs P have negative slope. Such behavior of dielectric properties and sigma(ac) can be attributed to illumination induced electron-hole pairs under illumination effect in the depletion region of SDs. The obtained results under illumination suggest that these devices can be used as a sensor in optical applications

On the possible conduction mechanisms in Rhenium/n-GaAs Schottky barrier diodes fabricated by pulsed laser deposition in temperature range of 60-400K

YILDIRIM, Mert/0000-0002-8526-1802WOS: 000468050800097AbstarctThis study presents electrical characteristics of n-GaAs based Schottky barrier diodes (SBDs) with Rhenium (Re) rectifier contacts. The electrical characteristics of the Re/n-GaAs SBDs were investigated utilizing the forward bias current-voltage (I-F-V-F) data collected in temperature range of 60-400K. The values of ideality factor (n) and zero-bias barrier height (phi(Bo)) were found as 9.10 and 0.11eV for 60K, and 1.384 and 0.624eV for 400K, respectively, on the basis of thermionic-emission theory. The conventional Richardson plot deviated from linearity at low temperatures and the Richardson constant value (A(*)) was obtained quite lower than the theoretical value for this semiconductor (8.16Acm(-2)K(-2)). nkT/q-kT/q plot shows that the field-emission may be dominant mechanism at low temperatures as a result of tunneling via surface states since the studied n-GaAs's doping concentration is on the order of 10(18) cm(-3), i.e. at high values so leads to tunneling. On the other hand, phi(Bo)-n, phi(Bo)-q/2kT and (n(-1)-1)-q/2kT plots exhibit linearity but this linearity is observed for two temperature regions (60-160K and 180-400K) due the presence of double Gaussian distribution (GD) of the barrier height. Therefore, the standard deviation value was obtained from the plot of phi(Bo)-q/2kT and it was used for modifying the conventional Richardson plot into the modified Richardson plot by which the values of mean barrier height and A(*) were obtained as 0.386eV and 15.55Acm(-2)K(-2) and 0.878eV and 8.35Acm(-2)K(-2) for the low and high temperature regions, respectively. As a result, I-F-V-F-T characteristics of the Re/n-GaAs SBDs were successfully elucidated by double-GD of barrier height

On the frequency dependent negative dielectric constant behavior in Al/Co-doped (PVC plus TCNQ)/p-Si structures

WOS: 000340097400004The dielectric properties, electric modulus and ac electrical conductivity (sigma(ac)) of Al/Co-doped (PVC + TCNQ)/p-Si structures have been investigated in the wide frequency and voltage range of 0.5 kHz-3 MHz and (-4 V)-( 9 V), respectively, using the capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements at room temperature. The real and imaginary parts of dielectric constant (epsilon ', epsilon ''), loss tangent (tan delta), sigma(ac) and the real and imaginary parts of electric modulus (M ', M '') were found strongly function of frequency and applied voltage especially at low frequencies. The epsilon '-V plot shows an anomalous peak in the forward bias region due to the series resistance (R-s), surface states (N-ss) and interfacial layer (PVC + TCNQ) effects for each frequency and then it goes to negative values known as negative dielectric constant (NDC) at low frequencies (f <= 70 kHz). Such observation of NDC is important result because it implies that an increment of bias voltage produces a decrease in the charge on the electrodes. The amount of negativity epsilon ' value increases with decreasing frequency and this decrement in the NDC corresponds to the increment in the epsilon ''

Analyses of temperature-dependent interface states, series resistances, and AC electrical conductivities of Al/p-Si and Al/Bi4Ti3O12/p-Si structures by using the admittance spectroscopy method

YILDIRIM, Mert/0000-0002-8526-1802WOS: 000326616700101In this study, Al/p-Si and Al/Bi4Ti3O12/p-Si structures are fabricated and their interface states (N-ss), the values of series resistance (R-s), and AC electrical conductivity (sigma(ac)) are obtained each as a function of temperature using admittance spectroscopy method which includes capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. In addition, the effect of interfacial Bi4Ti3O12 (BTO) layer on the performance of the structure is investigated. The voltage-dependent profiles of N-ss and R-s are obtained from the high-low frequency capacitance method and the Nicollian method, respectively. Experimental results show that N-ss and R-s, as strong functions of temperature and applied bias voltage, each exhibit a peak, whose position shifts towards the reverse bias region, in the depletion region. Such a peak behavior is attributed to the particular distribution of N-ss and the reordering and restructuring of N-ss under the effect of temperature. The values of activation energy (E-a), obtained from the slope of the Arrhenius plot, of both structures are obtained to be bias voltage-independent, and the E-a of the metal-ferroelectric-semiconductor (MFS) structure is found to be half that of the metal-semiconductor (MS) structure. Furthermore, other main electrical parameters, such as carrier concentration of acceptor atoms (N-A), built-in potential (V-bi), Fermi energy (E-F), image force barrier lowering (Delta Phi(b)), and barrier height (Phi(b)), are extracted using reverse bias C-2-V characteristics as a function of temperature

On the Anomalous Peak in the Forward Bias Capacitance and Dielectric Properties of the Al/Co-Doped (PVC plus TCNQ)/p-Si structures as Function of Temperature

WOS: 000357170600002The temperature and voltage dependence of electric and dielectric characteristics and ac electrical conductivity (sigma(ac)) of Al/Co-doped (PVC + TCNQ)/p-Si structure in the temperature range of 200-360 K and voltage range of (-4 V)-(9 V) have been investigated in detail by using experimental C-V and G/omega -V measurements at 500 kHz. The value of dielectric constant (epsilon'), dielectric loss (epsilon ''), dielectric loss tangent (tan delta), the real and imaginary parts of electric modulus (M' and M ''), and the sigma(ac) were strongly dependent applied bias voltage and temperature, especially in the depletion and accumulation regions. Such a behavior in these parameters can be explained on restructuring and reordering of charges at interface traps/states. The forward C-V plots exhibit an anomalous peak for each temperature and the peak position shift towards lower voltages with increasing temperature due to the particular density distribution of interface traps (D-it) and series resistance (Rs) of structure. Therefore the plots of dielectric properties and also sigma(ac) indicate two different behaviors before and after intersection point. Before this intersection point, while the values of the epsilon', epsilon '', and sigma(ac) increase, the tan delta decreases, after this intersection point, while the value of the epsilon', epsilon '', and sigma(ac) decrease, the tan delta increases. The ln (sigma(ac))-q/kT plot shows two linear regions both for the 2 V and 9 V which are corresponding to below room temperature (200-300 K) and above room temperature (320-360 K) and the corresponding activation energy (E-a) values were called as Ea((I)) and Ea((II)), respectively. Thus the E-a values were obtained from the slope of these Arrhenius plot as 182 meV and 4.7 meV for 2 V and 22 meV and 0.6 meV for 9 V, respectively