Electrical Properties

The electrical properties of double perovskite Ho2NiTiO6 (HNT) are investigated by impedance spectroscopy in the temperature range 30–420 °C and frequency range 100 Hz to 1 MHz. The X-ray diffraction analysis reveals that the compound crystallizes in monoclinic phase. The imaginary part of impedance (Z″) as a function of frequency shows Debye type relaxation. The frequency dependence of Z″ peak is found to obey an Arrhenius law with an activation energy of 0.129 eV. Impedance data presented in the Nyquist plot (Z″ vs. Z′) are used to identify an equivalent circuit and to know the bulk and interface contributions. The complex impedance analysis of HNT exhibits the appearance of both the grain and grain-boundary contribution. The results of bulk ac conductivity as a function of temperature and frequency are presented. The activation energy (0.129 eV), calculated from the slope of log τ versus 103/T plot, is found to be the nearly same as calculated (0.130 eV) from dc conductivity. The frequency dependent conductivity spectra obey the power law.

We present a new thin-film solar cell structure in which the traditional transparent conductive oxide electrode (ZnO) is replaced by a transparent conductive coating consisting of a network of bundled single-wall carbon nanotubes. Optical transmission properties of these coatings are presented in relation to their electrical properties (sheet resistance), along with preliminary solar cell results from devices made using CuIn1-xGaxSe2 thinfilm absorber materials. Achieving an energy conversion efficiency of >12% and a quantum efficiency of ~80% demonstrate the feasibility of the concept. A discussion of the device structures will be presented considering the physical properties of the new electrodes comparing current-voltage results from the new solar cell structure and those from standard ZnO/CdS/Cu(In,Ga)Se2/Mo solar cells.

Embedded resistor circuits have been generated with the use of a Micropen system, Ag conductor paste (DuPont 6142D), a new experimental resistor ink from DuPont (E84005-140), and Low Temperature Co-fired Ceramic (LTCC) green tape (DuPont A951). Sample circuits were processed under varying peak temperature ranges (835°C–875°C) and peak soak times (10 min–720 min). Resistors were characterized by SEM, TEM, EDS, and high-temperature XRD. Results indicate that devitrification of resistor glass phase to Celcian, Hexacelcian, and a Zinc-silicate phase occurred in the firing ranges used (835–875°C) but kinetics of divitrification vary substantially over this temperature range. The resistor material appears structurally and chemically compatible with the LTCC. RuO2 grains do not significantly react with the devitrifying matrix material during processing. RuO2 grains coarsen significantly with extended time and temperature and the electrical properties appear to be strongly affected by the change in RuO2 grain size.

Indium tungsten oxide (In6WO12) powders and thin films were prepared from a 2,4-pentanedione solution containing In(NO3)·xH2O and WCl6. X-ray diffraction results indicated that phase-pure In6WO12 powder formed after drying and heating the solution at 900 °C. Glancing X-ray diffraction results indicated that thin-film samples prepared on fused quartz substrates at 600 and 700 °C contained a disordered fluorite-related phase whereas those prepared at 800 °C contained the ordered compound—In6WO12. Films prepared at 900 °C reacted with the substrate to form In2Si2O7. Despite the chemical and structural similarity of In6WO12 to several indium-containing fluorite-related oxides, including In2O3, In3Sn4O12, and Ga3−xIn5+xSn2O16, the resistivity of the films prepared in this study ranged from 70 to 720 Ω cm, which is several orders of magnitude higher than reported for the related oxides (approx. 10−3 Ω cm). The band gaps of the films prepared at 600 and 700 °C were estimated from optical transmittance measurements to be 4.1 and 3.8 eV, respectively. Films prepared at 700 °C exhibited substantial coloration when exposed to n-butyl lithium whereas those prepared at 800 °C did not.

In this paper, we discuss the synthesis of carbon-sulfur composite (a-C:S) films by vapour phase pyrolysis of maleic anhydride and sulfur. Structural changes in the system are analysed by scanning electron microscopy and powder X-ray diffraction. Microhardness test depicts an increase in the value of hardness with an increase in sulfur concentration. Electrical conductivity of composite samples varies with sulfur concentration. Magnetoresistance (MR) measurements show a drastic increase in the value of MR for the samples prepared at < 900°C. Thermal stability of these samples is analysed by thermogravimetric analysis, which depends on the host structure and the amount of intercalated species.

By varying the concentration of surfactant in reverse micelle system, Ag particles from 10 to 200 nm in average diameter were synthesized, which have been characterized by X-ray diffraction and transmission electron microscopy. Isotropical conductive adhesives (ICAs) were prepared by using Ag particles as conductive fillers. It was found that the percolation threshold of ICAs depends on the filler size, which reaches to 63 wt.% when the filler average particle diameter is 50 nm. Results obtained by theoretical calculation are in good agreement with the experimental results.

Dielectric properties of some conducting polymers were investigated and their electrical properties are compared with each other. Temperature dependencies of their electrical properties are investigated throughout the work. Electrical behaviors of the synthesized systems constitute a good infrastructure for both understanding the intrinsic mechanisms and optimizing new synthesizes. It is found that, it can be possible to attain desired electrical properties by small synthesis modulations in thiophene based polymer materials.

The aim of this study is to understand the effect of the glass frit chemistry used in thick-film Ag pastes on the electrical performance of the silicon solar cell. The study focuses on the physical behavior of the glass frit during heat treatment as well as the resulting Ag−Si contact interface structure. We observe that the glass frit transition temperature (Tg) and softening characteristics play a critical role in the contact interface structure. The glass transition temperature also significantly influences the contact ohmicity of the thick-film metal grid. A high glass frit transition temperature generally results in thinner glass regions between the Ag bulk of the grid and the Si emitter. It was found that a glass frit (with high Tg) that crystallizes fast during the firing cycle after etching the silicon nitride and Si emitter results in smaller Ag crystallite precipitation at the contact interface. This results in smaller junction leakage current density (Jo2) and higher open-circuit voltage (Voc). Using high Tg pastes (with the appropriate Ag powder size), greater than 0.78 fill factors and >17.4% efficiency were achieved on 4 cm2 untextured single crystal Si solar cells with 100 Ω/sq emitters.

PbZr0.53Ti0.47O3 films were deposited on Si-SiO2-Ta-Pt substrates via a conventional sol-gel procedure. Electrical properties of the films were: resistivity ca. 5 × 1011 Ωcm, relative dielectric permittivity 900-1100, remnant polarization ca. 20 μC/cm2, breakdown electric field larger than 50 MV/m. The deflection amplitude of piezoelectrically excited Si cantilevers, covered with SiO2-Ta-Pt-PZT-Al, was determined with the aid of a heterodyne Mach-Zehnder

The crystallization behaviour of some soda lime silicate glasses modified by ZnO/CaO replacement to give the composition (Na2O)2·CaO1−x ·(ZnO)x ·3SiO2 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been investigated using differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD). The thermal expansion coefficients and AC electrical properties in the frequency range 40 Hz–5 MHz of the obtained crystalline products were determined. Two forms of sodium calcium silicate (Na4CaSi3O9 & Na2Ca2Si3O9), sodium metasilicate-Na2SiO3, two types of sodium zinc silicate (Na1.31Zn0.655Si1.345O4 & Na2ZnSiO4) and α-quartz phases were mostly developed in the crystallized glasses using various heat-treatment processes. The coefficient of thermal expansion of the obtained glass–ceramic materials are between 120 × 10−7°K−1 and 168 × 10−7°K−1 in the 25°–600 °C temperature range. The increase of frequency generally resulted in the increase of the conductivity and decrease the dielectric constant together with the loss tangent of the glass–ceramic materials.

A ferroelectric crystal exhibits a stable and switchable electrical polarization that is manifested in the form of cooperative atomic displacements. A ferromagnetic crystal exhibits a stable and switchable magnetization that arises through the quantum mechanical phenomenon of exchange. There are very few &#x27;multiferroic&#x27; materials that exhibit both of these properties, but the &#x27;magnetoelectric&#x27; coupling of magnetic and electrical properties is a more general and widespread phenomenon. Although work in this area can be traced back to pioneering research in the 1950s and 1960s, there has been a recent resurgence of interest driven by long-term technological aspirations.