scholarly journals Frequency and Voltage-dependent Electrical Parameters, Interface Traps, and Series Resistance Profile of Au/(NiS:PVP)/n-Si Structures 

2021 ◽  
Author(s):  
Murat Ulusoy ◽  
Ş. Altındal ◽  
Perihan Durmuş ◽  
Süleyman Özçelik ◽  
Yashar Azizian Kalandaragh
Keyword(s):  
Series Resistance ◽  
Relaxation Times ◽  
Low Frequency ◽  
Surface States ◽  
Interface Layer ◽  
Voltage Profile ◽  
Electrical Parameters ◽  
Doping Density ◽  
Insulator Layer ◽  
Layer Width

Abstract A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact were prepared on the surface by the sputtering method and then their basic electrical features for example diffusion-potential (VD), doping density of donor-atoms (ND), Fermi-energy (EF), barrier-height (ΦB), and depletion layer-width (WD) were extracted reverse-bias C-2-V plots as function frequency and voltage. The voltage profile of interface/surface-states (Nss)/ relaxation-times (τ), and series resistance (Rs) were also obtained from the admittance and Nicollian-Brews method, respectively. Strongly frequency-dependent and voltage especially in both accumulation and depletion regions due to the existence of Nss, Rs, and polarization as well as (NiS-doped PVP) organic interlayer. At low frequency, the observed higher value of C and G shows that thin (NiS:PVP) interlayer can be successfully used to obtain high charges/energy storage (MPS) structure/capacitor instead of conventional insulator layer performed traditional methods. As a result, the observed important changes in electrical parameters with frequency and voltage depend on Nss, their t, Rs, organic interlayer, and interfacial or dipole polarization.

Comparison of the electrical and impedance properties of Au/(ZnOMn:PVP)/ n-Si (MPS) type Schottky-diodes (SDs) before and after gamma-irradiation

2021 ◽  
Author(s):  
Şemsettin Altindal ◽  
Ali Barkhordari ◽  
Gholamreza Pirgholi-Givi ◽  
Murat Ulusoy ◽  
Hamid Reza Mashayekhi ◽  
...  
Keyword(s):  
Electric Field ◽  
Gamma Irradiation ◽  
Schottky Diodes ◽  
Linear Part ◽  
Thermionic Emission ◽  
Surface States ◽  
Electrical Parameters ◽  
Layer Width ◽  
Before And After ◽  
Voltage Dependent

Abstract The effect of 60Co-irradiation) on the electrical parameters in the Au/(ZnOMn:PVP)/n-Si SDs has been investigated using the current-voltage (I-V) and capacitance/conductance-voltage (C/G-V) measurements. Firstly, the values of reverse-saturation-current (Io), ideality-factor (n), barrier-height (BH), shunt/series resistances (Rsh, Rs), and rectifying-rate (RR) were extracted from the I-V data before and after gamma-irradiation (5 and 60 kGy) using thermionic-emission (TE), Norde, and Cheung methods. The surface-states (Nss) versus energy (Ec-Ess) profile was extracted from I-V data considering voltage-dependent of n and BH using the Card-Rhoderick method. Secondly, the doping-donor atoms (Nd), Fermi-energy (EF), BH, maximum electric-field (Em), and depletion-layer width (Wd) were extracted from the linear-part of reverse-bias C-2-V plot for 100 kHz before and after irradiation. Finally, the voltage-dependent profiles of Rs and radiation-induced of Nss were extracted from the C/G-V plots by using Nicollian-Brews and the difference between C-V plots before and after irradiation, respectively. The peak behavior in the Nss-V plots and shifts in its position was attributed to special-distribution of Nss at (ZnOMn:PVP)/n-Si interface and restructure/reordering of them under radiation and electric field. Experimental results show that gamma-irradiation is more effective both on the I-V and C/G-V plots or electrical parameters, and hence the fabricated Au/(ZnOMn:PVP)/n-Si SDs can be used as a radiation-sensor.

On the negative capacitance behavior in the forward bias of Au/n–4H–SiC (MS) and comparison between MS and Au/TiO2/n–4H–SiC (MIS) type diodes both in dark and under 200 W illumination intensity

2014 ◽  
Vol 29 (01) ◽  
pp. 1450237 ◽  
Author(s):  
H. G. Çetinkaya ◽  
D. E. Yıldız ◽  
Ş. Altındal
Keyword(s):  
Ideality Factor ◽  
Dielectric Material ◽  
Forward Bias ◽  
Reverse Current ◽  
Surface States ◽  
Negative Capacitance ◽  
Distribution Profile ◽  
Insulator Layer ◽  
Layer Width ◽  
Energy Density Distribution

In order to see the effect of interfacial layer on electrical characteristics both Au /n–4 H – SiC (MS) and Au/TiO 2/n–4 H – SiC (MIS) type Schottky barrier diodes (SBDs) were fabricated and their main electrical parameters were investigated by using the forward and reverse bias current-voltage (I–V), capacitance/conductance-voltage (C/G–V) measurements at room temperature. The ideality factor (n), series and shunt resistances (Rs, Rsh), barrier height (BH), depletion layer width (WD) and the concentration of donor atoms (ND) were obtained before and after illumination. The energy density distribution profile of surface states (Nss) was also obtained by taking into account voltage dependent effective BH (Φe) and ideality factor (nV). All of these experimental results confirmed that the use of a high dielectric material or insulator layer ( TiO 2) between metal and semiconductor leads to improvements in the diode performance in terms of Rs, Rsh, BH, Nss and rectifier rate (RR = IF/IR for sufficiently high forward and reverse current). Another important result is the negative capacitance (NC) behavior observed in the forward bias C–V plot for the Au /n–4 H – SiC (MS) diode, but it disappears in Au/TiO 2/n–4 H – SiC (MIS) diode and also the minimum value of C–V plot corresponds to maximum value of G/ω–V plot in the accumulation region. Such behavior of NC shows that the material displays an inductive behavior.

Dielectric Relaxation Studies of Silver Nanoparticles dispersed Liquid Crystal

2015 ◽  
Vol 8 (3) ◽  
pp. 2176-2188 ◽  
Author(s):  
Keisham Nanao Singh
Keyword(s):  
Activation Energy ◽  
Silver Nanoparticles ◽  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Relaxation Times ◽  
Low Frequency ◽  
Bulk Liquid ◽  
Molecular Rearrangement ◽  
Relaxation Studies

This article reports on the Dielectric Relaxation Studies of two Liquid Crystalline compounds - 7O.4 and 7O.6 - doped with dodecanethiol capped Silver Nanoparticles. The liquid crystal molecules are aligned homeotropically using CTAB. The low frequency relaxation process occurring above 1 MHz is fitted to Cole-Cole formula using the software Dielectric Spectra fit. The effect of the Silver Nanoparticles on the molecular dipole dynamics are discussed in terms of the fitted relaxation times, Cole-Cole distribution parameter and activation energy. The study indicate a local molecular rearrangement of the liquid crystal molecules without affecting the order of the bulk liquid crystal molecules but these local molecules surrounding the Silver Nanoparticles do not contribute to the relaxation process in the studied frequency range. The observed effect on activation energy suggests a change in interaction between the nanoparticles/liquid crystal molecules.

scholarly journals Determination of the Distribution of Relaxation Times by Means of Pulse Evaluation for Offline and Online Diagnosis of Lithium-Ion Batteries

Batteries ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 36
Author(s):  
Erik Goldammer ◽  
Julia Kowal
Keyword(s):  
Lithium Ion Batteries ◽  
Electrochemical Impedance ◽  
Sampling Rate ◽  
Relaxation Times ◽  
Low Frequency ◽  
Lithium Ion ◽  
Battery Management ◽  
Time Constants ◽  
Time Domain Data ◽  
Aging Study

The distribution of relaxation times (DRT) analysis of impedance spectra is a proven method to determine the number of occurring polarization processes in lithium-ion batteries (LIBs), their polarization contributions and characteristic time constants. Direct measurement of a spectrum by means of electrochemical impedance spectroscopy (EIS), however, suffers from a high expenditure of time for low-frequency impedances and a lack of general availability in most online applications. In this study, a method is presented to derive the DRT by evaluating the relaxation voltage after a current pulse. The method was experimentally validated using both EIS and the proposed pulse evaluation to determine the DRT of automotive pouch-cells and an aging study was carried out. The DRT derived from time domain data provided improved resolution of processes with large time constants and therefore enabled changes in low-frequency impedance and the correlated degradation mechanisms to be identified. One of the polarization contributions identified could be determined as an indicator for the potential risk of plating. The novel, general approach for batteries was tested with a sampling rate of 10 Hz and only requires relaxation periods. Therefore, the method is applicable in battery management systems and contributes to improving the reliability and safety of LIBs.

Effects of director rotation relaxation on viscoelastic wave dispersion in nematic elastomer beams

2018 ◽  
Vol 24 (4) ◽  
pp. 1103-1115 ◽  
Author(s):  
Dong Zhao ◽  
Ying Liu
Keyword(s):  
Wave Motion ◽  
Relaxation Times ◽  
Low Frequency ◽  
Wave Dispersion ◽  
Frequency Limit ◽  
Anisotropic Parameter ◽  
Acoustic Design ◽  
Phase Velocities ◽  
Nematic Elastomer ◽  
Viscoelastic Wave

In this paper, the transverse wave dispersion in a nematic elastomer (NE) Timoshenko beam is studied by considering anisotropy and viscoelasticity of NEs in the low frequency limit. Firstly, the characteristic equations of wave motion in an NE beam are derived, and then numerically solved to obtain the corresponding phase velocities and attenuation factors. The influences of anisotropic parameter, director rotation and rubber relaxation times on the wave dispersion in an NE beam are discussed. Results show that unlike the situation in general isotropic viscoelastic beam, non-classical viscoelastic wave dispersion is found in NE beams. Geometric dispersion is restrained with the vanishing of cut-off frequencies for shear waves due to director rotation relaxation of NEs. This unique property promises prospective applications of NE beams in optic or acoustic design.

Topological phase and thermoelectric properties of bialkali bismuthide compounds (Na,K)2RbBi from first-principles

2021 ◽  
Author(s):  
Shahram Yalameha ◽  
Zahra Nourbakhsh ◽  
Daryoosh Vashaee
Keyword(s):  
Density Functional ◽  
Transport Coefficients ◽  
Relaxation Times ◽  
Surface States ◽  
Topological Phase ◽  
Boltzmann Transport ◽  
Thermoelectric Power Factor ◽  
Practical Applications ◽  
Wide Range ◽  
P Type

Abstract We report the topological phase, thermal, and electrical properties of bialkali bismuthide compounds (Na,K)2RbBi, as yet hypothetical. The topological phase transitions of these compounds under hydrostatic pressure are investigated. The calculated topological surface states and Z2 topological index confirm the nontrivial topological phase. The electronic properties and transport coefficients are obtained using the density functional theory combined with the Boltzmann transport equation. The relaxation times are determined using the deformation potential theory to calculate the electronic thermal and electrical conductivity. The calculated mode Grüneisen parameters are substantial, indicating strong anharmonic acoustic phonons scattering, which results in an exceptionally low lattice thermal conductivity. These compounds also have a favorable thermoelectric power factor leading to a relatively flat p-type figure-of-merit over a broad temperature range. Furthermore, the mechanical properties and phonon band dispersions show that these structures are mechanically and dynamically stable. Therefore, they offer excellent candidates for practical applications over a wide range of temperatures.

Time Domain Zero Field NMR and NQR

1986 ◽  
Vol 41 (1-2) ◽  
pp. 440-444 ◽  
Author(s):  
A. Bielecki ◽  
D. B. Zax ◽  
A. M. Thayer ◽  
J. M. Millar ◽  
A. Pines
Keyword(s):  
Time Domain ◽  
Relaxation Times ◽  
Low Frequency ◽  
High Sensitivity ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Zero Field ◽  
Spin Lattice ◽  
Field Cycling ◽  
The Time Domain

Field cycling methods are described for the time domain measurement of nuclear quadrupolar and dipolar spectra in zero applied field. Since these techniques do not involve irradiation in zero field, they offer significant advantages in terms of resolution, sensitivity at low frequency, and the accessible range of spin lattice relaxation times. Sample data are shown which illustrate the high sensitivity and resolution attainable. Comparison is made to other field cycling methods, and an outline of basic instrumental requirements is given.

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