677 research outputs found
Dielectric characteristics of gamma irradiated Au/SnO2/n-Si/Au (MOS) capacitor
No full textInternational Semiconductor Science and Technology Conference (ISSTC) -- JAN 13-15, 2014 -- Istanbul, TURKEYTataroglu, Adem/0000-0003-2074-574X; YILDIRIM, Mert/0000-0002-8526-1802WOS: 000345645000016The dielectric characteristics of gamma irradiated Au/SnO2/n-Si/Au (MOS) capacitor were studied. The MOS capacitor was irradiated by a Co-60 gamma radiation source with a dose rate of 0.69 kGy/h. The dielectric parameters such as dielectric constant (epsilon'), dielectric loss (epsilon ''), loss factor (tan delta) and ac electrical conductivity (sigma(ac)) were calculated from the capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements. It is found that the C and G/omega values decrease with the increasing total dose due to the irradiation-induced defects at the interface. Also, the calculated values of epsilon', epsilon '' and sigma(ac) are found to decrease with an increased radiation dose. This result indicates that the dielectric characteristics of the MOS capacitor are sensitive to gamma-ray dose. (C) 2014 Elsevier Ltd. All rights reserved
Supplementary_Material_R1 – Supplemental material for A bioartificial rat heart tissue: Perfusion decellularization and characterization
No full textSupplemental material, Supplementary_Material_R1 for A bioartificial rat heart tissue: Perfusion decellularization and characterization by Busra Ozlu, Mert Ergin, Sevcan Budak, Selcuk Tunali, Nuh Yildirim and Cevat Erisken in The International Journal of Artificial Organs</p
Influence of interfacial layer thickness on frequency dependent dielectric properties and electrical conductivity in Al/Bi4Ti3O12/p-Si structures
No full textYILDIRIM, Mert/0000-0002-8526-1802WOS: 000345215500025Three Al/Bi4Ti3O12/p-Si structures were fabricated with different interfacial layer thickness values (10, 25, and 53 nm) and admittance measurements of the structures were carried out between 1 kHz and 1 MHz in order to investigate the influence of interfacial layer thickness on dielectric properties of these structures. For the structure with thicker interfacial layer, higher dielectric constant (epsilon') and dielectric loss (epsilon '') values were obtained at low frequencies. At high frequencies, these parameters tend to be saturated and become almost constant. Loss tangent versus frequency plots exhibit a peak and magnitude of the peak weakens with increasing frequency and shifts toward high frequency region. The dispersion in epsilon' and epsilon '' with varying thickness at low frequencies was ascribed to interfacial polarization. In addition, obtained epsilon '' values indicated higher energy dissipation in the structure with thicker interfacial layer. Admittance data of the structures were also considered in terms of modulus formalism to interpret the relaxation processes in the structures. Moreover, dc electrical conductivity values were derived using frequency dependent ac electrical conductivity of the structures. (C) 2014 American Vacuum Society
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
No full textYILDIRIM, 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
The effect of gamma irradiation on electrical and dielectric properties of organic-based Schottky barrier diodes (SBDs) at room temperature
No full text/0000-0002-0094-7427; YILDIRIM, Mert/0000-0002-8526-1802WOS: 000301016100003The effect of Co-60 (gamma-ray) irradiation on the electrical and dielectric properties of Au/Polyvinyl Alcohol (Ni,Zn-doped)/n-Si Schottky barrier diodes (SBDs) has been investigated by using capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements at room temperature and 1 MHz. The real capacitance and conductance values were obtained by eliminating series resistance (R-s) effect in the measured capacitance (C-m) and conductance (G(m)) values through correction. The experimental values of the dielectric constant (epsilon'), dielectric loss (epsilon ''), loss tangent (tan delta), ac electrical conductivity (sigma(ac)) and the real (M') and imaginary (M '') parts of the electrical modulus were found to be strong functions of radiation and applied bias voltage, especially in the depletion and accumulation regions. In addition, the density distribution of interface states (N-ss) profile was obtained using the high-low frequency capacitance (C-HF-C-LF) method for before and after irradiation. The N-ss-V plots give two distinct peaks for both cases, namely before radiation and after radiation, and those peaks correspond to two different localized interface states regions at M/S interface. The changes in the dielectric properties in the depletion and accumulation regions stem especially from the restructuring and reordering of the charges at interface states and surface polarization whereas those in the accumulation region are caused by series resistance effect. (C) 2011 Elsevier Ltd. All rights reserved
MERT HANDAN,COMBA BAHAT,MERT NİHAT,ÇINAR DURSUNALİ,APAYDIN YILDIRIM BETÜL, Advanced oxidation protein products AOPP levels and kidney function in fluorotic sheep, Fluoride, vol.49, pp.336-342, 2016
No full textOn the possible conduction mechanisms in Rhenium/n-GaAs Schottky barrier diodes fabricated by pulsed laser deposition in temperature range of 60-400K
No full textYILDIRIM, 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
Investigation of the inhomogeneous barrier height of an Au/Bi4Ti3O12/n-Si structure through Gaussian distribution of barrier height
No full textYILDIRIM, Mert/0000-0002-8526-1802; Gokcen, Muharrem/0000-0001-9063-3028WOS: 000314221400083A Au/Bi4Ti3O12/n-Si structure is fabricated in order to investigate its current-voltage (I-V) characteristics in a temperature range of 300 K-400 K. Obtained I-V data are evaluated by the thermionic emission (TE) theory. Zero-bias barrier height (Phi(B0)) and ideality factor (n) calculated from I-V characteristics, are found to be temperature-dependent such that Phi(B0) increases with temperature increasing, whereas n decreases. The obtained temperature dependence of Phi(B0) and linearity in Phi(B0) versus the n plot, together with a lower barrier height and Richardson constant values obtained from the Richardson plot, indicate that the barrier height of the structure is inhomogeneous in nature. Therefore, I-V characteristics are explained on the basis of Gaussian distribution of barrier height.Duzce UniversityDuzce University [2010.05.02.056, 2012.05.02.110]Project supported by the Duzce University Scientific Research Project (Grant Nos. 2010.05.02.056 and 2012.05.02.110)
Investigation of current-voltage characteristics and current conduction mechanisms in composites of polyvinyl alcohol and bismuth oxide
No full textWOS: 000340659600010Temperature dependent current-voltage (I-V) measurements of Au/Polyvinyl Alcohol+Bi2O3/n-Si structure were conducted between 100 and 350 K for investigating the temperature dependence of I-V characteristics and current conduction mechanisms in the structure. Series resistance of the structure is calculated using Ohm's law and Cheungs' method. Ideality factor (n) and zero-bias barrier height (Phi(Bo)) were obtained considering thermionic emission theory. From 100 to 350 K, n changed from 32.1 to 3.54, and Phi(Bo) changed from 0.27 to 0.99 eV. Obtained temperature dependent values of n and Phi(Bo) suggested that thermionic emission is not the dominant current conduction mechanism. Therefore, Ln(I)-Ln(V) curves of the studied structure were plotted for investigating current conduction mechanisms in the structure and current flow is explained considering space charge limited current. Moreover, density of interface states (D-it) in the structure were calculated and its temperature dependence was investigated such that D-it values are reduced to the order of similar to 10(13) eV(-1) cm(-2) from similar to 10(14) eV(-1) cm(-2) with increasing temperature. (C) 2013 Society of Plastics EngineersDuzce University Research Fund [2012.05.02.110]This project is supported by Duzce University Research Fund Project Number 2012.05.02.110
Controlling the electrical characteristics of Al/p-Si structures through Bi4Ti3O12 interfacial layer
No full textYILDIRIM, 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
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