Complex Admittance Method Research Articles

Effects of series and parallel resistances on the C-V characteristics of silicon-based metal oxide semiconductor (MOS) devices

This paper investigates the electrical behavior of the Al/SiO2/Si MOS structure. We have used the complex admittance method to develop an analytical model of total capacitance applied to our proposed equivalent circuit. The charge density, surface potential, semiconductor capacitance, flatband and threshold voltages have been determined by resolving the Poisson transport equations. This modeling is used to predict in particular the effects of frequency, parallel and series resistance on the capacitance-voltage characteristic. Results show that the variation of both frequency and parallel resistance causes strong dispersion of the C-V curves in the inversion regime. It also reveals that the series resistance influences the shape of C-V curves essentially in accumulation and inversion modes. A significant decrease of the accumulation capacitance is observed when Rs increases in the range 200–50000 Ω. The degradation of the C-V magnitude is found to be more pronounced when the series resistance depends on the substrate doping density. When Rs varies in the range 100 Ω–50 kΩ, it shows a decrease in the flatband voltage from −1.40 to −1.26 V and an increase in the threshold voltage negatively from −0.28 to −0.74 V, respectively. Good agreement has been observed between simulated and measured C-V curves obtained at high frequency. This study is necessary to control the adverse effects that disrupt the operation of the MOS structure in different regimes and optimizes the efficiency of such electronic device before manufacturing.

Protonic conductivity and ferroelastic instability in triammonium hydrogen disulphate: a dielectric and neutron diffraction study

The protonic conductivity of has been measured using the complex-admittance method in the frequency range 30 Hz-200 MHz and the temperature interval 290-500 K covering both the ferroelastic and the paraelastic phases. The dc conductivity shows quasi-two-dimensional behaviour and in the trigonal paraelastic phase its values in the (001) plane are typically super-protonic with low activation enthalpy . The temperature dependence of the monoclinic superstructure reflection 120 has been studied using elastic neutron diffraction. It was found that the observed anomalies of the macroscopic and microscopic quantities, such as the morphic birefringence and the high-frequency dielectric constant on the one hand and the diffusion proton dynamics as well as the integrated intensity of the reflection 120 on the other hand, show pronounced differences in their temperature evolution below the ferroelastic phase transition temperature. The neutron scattering results as well as the dielectric measurements indicate precursor effects above . The results are discussed on the basis of a phenomenological two-order-parameter model for the - ferroelastic phase transition. It is argued that properties which originate from the disorder of the oxygen and proton subsystem can be described by irreducible representations of the wave vector at the point and the L point of the Brillouin zone, while properties which originate from displacements of the heavy atoms (the displacement mode) are solely described by the wave vector at the L point of the Brillouin zone of the paraphase.

Effect of Microstructure and Composition on Ionic Conductivity of Rare‐Earth Oxide‐Doped Ceria

Polycrystalline ceria doped with several rare‐earth oxides (, and ) at various concentrations were fabricated. Conductivity was measured by ac admittance and dc four‐probe methods. The conductivity was separated into grain and grain boundary contributions using complex admittance technique as well as the grain size dependence of conductivity. The effect of dopant type and concentration on grain boundary conductivity was examined. Grain size dependence of polycrystalline conductivity, which can be adequately described by the so‐called brick layer model, appears to give a more reliable measure of the grain conductivity compared to the complex admittance method. Polycrystalline resistivity (1/conductivity) increases linearly with the reciprocal of grain size. The intercept of resistivity vs. inverse grain size plot gives a measure of the grain resistivity, and the slope gives a measure of the grain boundary resistivity. Activation energies of polycrystalline conductivity, grain conductivity, and grain boundary conductivity were determined. A compositional analysis of fractured samples was carried out by Auger spectroscopy. The dopant concentration near grain boundaries was estimated to be lower than that in the bulk.

Protonic conductivity of (NH 4) 4Fe(CN) 6·1.5H 2O by complex admittance method

The protonic conductivity of ammonium ferrocyanide hydrate has been studied by the complex admittance method. The admittance plots show departures from ideal Debye behaviour. The values of ionic conductivity (σ=3.7×10 −5 (Ω cm) −1) and diffusion coefficient (D=3.8×10 −10 cm 2/s) obtained at room temperature are consistent with the corresponding values estimated by an earlier NMR study.

Characterization of KTaWO 6·H 2O

The pyrochlore-type compound KTaWO 6·H 2O has been characterized by X-ray diffraction technique, thermogravimetric analysis and differential scanning calorimetry. Electrical conductivity measurements have been carried out in the temperature range 25–500°C by complex admittance method.

Influence of stoichiometry and the nature of the spinel-block stabilizing element on proton transport behavior in solid electrolytes with the β″-alumina structure

As an extension of prior work done in this laboratory on proton transport in NH + 4-H 3O + β″-alumina, we reported here new proton diffusion coefficient and conductivity measurements on: (a) magnesia-stabilized NH + 4-H 3O + β″-alumina crystals with a substantially different stoichiometry than that reported earlier; and (b) NH + 4-H 3O + β″-gallate crystals where stabilization of the as-grown crystal involves sodium substitution in the spinel block. Proton diffusion coefficients of both compounds were measured over the temperature range 300–450K with the aid of a pulsed field gradient NMR technique, whereas a complex admittance method was used to obtain the protonic conductivities reported here for the same temperature interval. In the light of the present and earlier observations of protonic transport behavior, ideas were discussed concerning; (a) possible mechanisms of proton transport and (b) the role played by stoichiometry and the type of spinel-block stabilizing element in these β″ materials.

Electrical properties of ZnO stabilized beta″-alumina

The electrical conductivity of ZnO doped (1−5 wt%) beta″-alumina ceramic samples has been measured by the complex admittance method. The smallest value of electrical resistivity was in the case of the samples doped with 3 wt% ZnO. The bulk conductivity dependence (in ln σT−1/ T coordinates) is characterized by two slopes, with a bend occuring at about 250°C. The low temperature activation energy of bulk conductivity is not influenced by the doping level. The high temperature activation energy decreases with increasing ZnO content. The change in the slope of the Arrhenius plot of the beta-alumina bulk conductivity is in agreement with what should be expected from Wang's model.

Study on the electrical properties and phase transitions of lithium ferrite by a complex admittance method

The electrical properties of lithium ferrite (LiFeO 2) with rock-salt structure have been studied as a function of temperature (380–700°C) and oxygen partial pressure ( 2.1 × 10 4 −5.3 Pa) using AC conductivity measurements. Data analysis in the complex admittance plane revealed the presence of three phase transitions and mixed (electronic and ionic) conduction in LiFeO 2. The nature of the charge carriers depends on temperature and oxygen partial pressure. The defect structure of α-LiFeO 2 at high temperature has been discussed from the oxygen partial pressure dependence of electronic conductivity.

Bulk and grain boundary electrical conductivities of NASICON

The ionic conductivity of ceramic samples of NASICON was investigated by the use of the complex admittance method. Measurements were made in the frequency range 5−5×10 5 Hz from room termparature (RT) up to 400°C. The existence of three activation energies for both the bulk and the grain boundary conductivities is reported. A diffusive Warburg-like behaviour of electrical conductivity was revealed at temperatures where the value of the bulk conductivity approaches that of the grain boundary.

Investigations of the ionic conductivity of CdF2 single crystals by the complex admittance method

physica status solidi (a)Volume 60, Issue 1 p. K65-K67 Short Note Investigations of the ionic conductivity of CdF2 single crystals by the complex admittance method F. Krok, F. Krok Institute of Physics, Warsaw Technical University Search for more papers by this authorW. Bogusz, W. Bogusz Institute of Physics, Warsaw Technical University Search for more papers by this authorW. Jakubowski, W. Jakubowski Institute of Physics, Warsaw Technical University Search for more papers by this author F. Krok, F. Krok Institute of Physics, Warsaw Technical University Search for more papers by this authorW. Bogusz, W. Bogusz Institute of Physics, Warsaw Technical University Search for more papers by this authorW. Jakubowski, W. Jakubowski Institute of Physics, Warsaw Technical University Search for more papers by this author First published: 16 July 1980 https://doi.org/10.1002/pssa.2210600157 Ul. Chodkiewicza 8, 02–594 Warsaw, Poland. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume60, Issue116 July 1980Pages K65-K67 RelatedInformation

Analysis of Electrolyte Polarization in Polycrystalline Sodium β‐Alumina by a Complex Admittance Method

The polarization behavior of lithia‐stabilized sodium β‐alumina in the form of polycrystalline pressed and sintered specimens was studied at 100° to 400°C by observing the isothermal values of the complex admittance from ≊5 Hz to 500 kHz. Analyzing these data in the complex admittance plane in terms of an equivalent circuit for the system made it possible, when ion‐blocking electrodes were used, to distinguish the separate contributions of the grain boundaries and the bulk crystals to the total electrolyte resistance. These results gave activation energies of 0.32 to 0.41 eV for the grain‐boundary resistance and 0.11 to 0.14 eV for the bulk resistance. The prefactors in the Arrhenius expressions for these resistances appeared to be more sensitive to factors such as specimen composition, microstructure, and specimen preparation conditions than are the activation energies.

Study of solid electrolyte polarization by a complex admittance method

The polarization behavior of zirconia-yttria solid electrolyte specimens with platinum electrodes has been studied over a temperature range of 400° to 800°C and a wide range of oxygen partial pressures. The complex admittance of these specimens was determined over a frequency range from d.c. to 100kHz. An analysis of these data in the complex admittance plane indicated the presence of three polarizations: (1) an electrode polarization characterized by a double layer capacity and an effective resistance for the overall electrode reaction, 1 2 O 2(gas) + 2 e(platinum) ⇇ O 2− (electrolyte); (2) a capacitive-resistive electrolyte polarization, probably corresponding to a partial blocking of oxygen ions at the electrolyte grain boundaries by an impurity phase there; and (3) a pure ohmic electrolyte polarization.

Study of solid electrolyte polarization by a complex admittance method

In this paper, the guidelines leading to the identification of the values of the parameters of the equivalent electric circuit of vibration electromagnetic harvesters are identified and discussed. A simplified closed form analysis of the non-linear system composed by a vibration electromagnetic harvester which supplies a DC load by means of a diode bridge rectifier is also presented. Such an analysis clearly puts in evidence that the maximum power which can be extracted by a given vibration harvester (when it supplies the optimal load impedance) is higher than the maximum power which can be extracted by such an harvester when it is cascaded with a diode bridge rectifier which supplies the optimal DC load. The term “optimal load” identifies in both cases the load in correspondence of which the electric power which is extracted from vibrations attains its maximum value.