Dependence Of Electrical Properties Research Articles

Composition dependent structural, morphological, optical and electrical properties of CdS:Co window layer grown by chemical bath deposition

CdS as an n–type layer plays an important role in the fabrication of solar cells. Cd1-xCoxS thin-films with variable Co doping levels (x = 0 to 0.06) were deposited on glass and indium tin oxide-coated (ITO) glass substrates by simple and inexpensive chemical bath deposition. The effects of Co doping on the structural, optical, morphological, elemental, and vibrational properties of CdS films were systematically examined. XRD results revealed that Co concentrations increase and the crystallite size of the film decreases from 20.4 to 13.6 nm due to the incorporation Co in Cd sites. The optical bandgap was reduced from 2.44 to 2.32 eV due to the incorporation of Co, which was found with a UV–Vis spectrophotometer. Urbach energy, refractive index and extinction coefficient of all deposited films was estimated, and the results were discussed. The intensity of PL peaks was reduced by increasing the Co concentration in the red region. The resistivity and carrier concentration were measured from Hall measurement system and the film current density was increased from 7 to 26 mA/cm2 by cobalt doping.

Electrical properties of medium voltage electricity distribution networks

An increasing amount of low carbon technologies (LCT) such as solar photovoltaic, wind turbines and electric vehicles are being connected at medium and low voltage levels to electric power networks. To support high-level decision-making processes, the impacts of the LCTs on large numbers of different types (e.g., rural, suburban, urban) of distribution networks need to be fully understood and quantified. However, detailed modeling of large numbers of real-world networks is challenging for two reasons. First, access to real-world network data is limited, and second, cleaning the data requires a significant amount of time, even before modeling of the networks. This paper offers a novel systematic methodology aimed at identifying and quantifying the key electrical properties of medium-voltage level distribution networks. The methodology allows for characterizing different types (e.g., suburban, urban) of distribution networks and obtaining 'depth' dependent electrical properties of the models of the networks. Two key sets of (electrical) data were used for the study. The first set was installed capacities of distribution substations; and the second set was the conductor cross sections of the distribution lines. In the graph models of real-world networks, 'nodes' represent the distribution sub­stations, switchgears, busbars and consumers locations of the network. 'Links/edges' stand for the connections between the nodes through distribution lines. The results of the investigation of the real-world networks showed that, the substation capacities and the conductor cross sections could characterize the electrical properties of suburban and urban type distribution networks. The resulted probability density functions (PDF) of the electrical properties of suburban and urban type distribution networks have the potential to be directly used in generating realistic distribution network models.

Optical and electrical properties of InGaZnON thin films**Project supported by the National Natural Science Foundation of China (Grant No. 61674107), Shenzhen Key Lab Fund, China (Grant No. ZDSYS 20170228105421966), and Science and Technology Plan of Shenzhen, China (Grant No. JCYJ20170302150335518).

The substrate temperature (Ts) and N2 partial pressure (PN2) dependent optical and electrical properties of sputtered InGaZnON thin films are studied. With the increased Ts and PN2, the thin film becomes more crystallized and nitrified. The Hall mobility, free carrier concentration (Ne), and electrical conductivity increase with the lowered interfacial potential barrier during crystal growing. The photoluminescence (PL) intensity decreases with the increased Ne. The band gap (Eg) narrows and the linear refractive index (n1) increases with the increasing concentration of N in the thin films. The Stokes shift between the PL peak and absorption edge decreases with Eg. The n1, dispersion energy, average oscillator wavelength, and oscillator length strength all increase with n1. The single oscillator energy decreases with n1. The nonlinear refractive index and third order optical susceptibility increase with n1. The Seebeck coefficient, electron effective mass, mean free path, scattering time, and plasma energy are all Ne dependent.

Dielectric Properties of Pulsed Laser Deposited Nanoscale CeNi5 Thin Films

Dielectric properties of pulsed laser deposited, nanoscale CeNi5 alloy layers, on glass or SiO2 substrate are described using the complex dielectric function. The UV–Vis–NIR spectral behavior of this function is studied separately for its real part e1 (the dielectric constant or dielectric permittivity), and for its imaginary part e2 (the dielectric loss function). The layers were obtained from grinded CeNi5 bulk powder using short, modulated laser pulses. The absolute reflectance of the obtained nanoscale alloy layers was measured at the 632.8 nm wavelength of a liquid nitrogen cooled and stabilized He–Ne source. This value was further used to renormalize the relative differential reflectance spectroscopy measurements performed in the UV‒Vis‒NIR domain. The obtained absolute reflectance spectra were processed using the Kramers–Kronig formalism, so that the real and imaginary parts of the complex dielectric function could be computationally determined, also leading to the calculation of the electron loss functions –Im e–1 and –Im(1 + e)–1. The behavior of these functions near the spectral inflexion points was determined using appropriate theoretical considerations. The variation of the dielectric functions was explained, electron density of states and the shape of the energy bands were inferred. This study reveals the layer thickness and deposition substrate dependent optical and electrical properties of the produced nanoscale CeNi5 structures.

Frequency and voltage dependent electrical properties of YMn0.90Os0.10O3 thin film on the SiO2/p-Si substrate

The YMn0.90Os0.10O3 (YMOO) thin film was deposited on the SiO2/p-Si substrate via using radio frequency (rf) magnetron sputter method. Voltage dependent electrical properties of the Al/YMOO/SiO2/p-Si/Al structure were investigated at various frequency and ambient condition. Capacitance-voltage (C-V) measurements showed that the capacitance has an accumulation region at positive or forward bias region. Conductance-voltage (G-V) characteristics of the device displayed that the G increases with increasing frequency. Series resistance, Rs, of the device was derived from C-V and G-V measurements and the Rs-V characteristic exhibited strongly frequency dependency. Frequency dependent interface state density, Nss, was calculated according to the Hill-Coleman relation, which decreases as frequency increases. The corrected capacitance (Cc) and conductance (Gc) results revealed that the effect of series resistance on the electrical properties cannot be ignored.

Photovoltaic effect on the microelectronic properties of perylene/p-Si heterojunction devices

This paper presents the fabrication and study of light dependent electrical properties of heterojunction device based on small molecular semiconductor 3, 4, 9, 10-perylene tetracarboxylic anhydride (PTCDA). The Ag/PTCDA/P3HT/p-Si heterojunction device is prepared by spin coating a 20 nm layer of poly-3,hexylthiophene (P3HT) on p-Si followed by 80 nm thick film of PTCDA via thermal deposition. Current–voltage (I–V) properties of the device are measured at room temperature in dark condition ~ 20 lx (lx) and different illumination conditions to probe photovoltaic effects on the microelectronic parameters of the device. In dark, the Ag/PTCDA/P3HT/p-Si device exhibited rectifying behavior in the forward bias with a current rectification ratio (RR) of 1990 at ± 3.5 V that confirmed the formation of depletion region. Key microelectronic parameters of the device such as ideality factor (n), barrier height (φb), series resistance (Rs) and shunt resistance (Rsh) are extracted from the I–V characteristics and studied as a function of illumination (2–2700 lx). Charge conduction mechanism and mobility via interface of the device is also investigated from logI–logV curves and conventional I–V characteristics, respectively. The microelectronic properties of the device are correlated with optical properties (absorption spectrum) and morphology of the PTCDA thin films carried out by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Fourier transformed infrared (FTIR) spectrum and energy dispersive x-rays (EDX) is performed to validate composition and elemental analysis of PTCDA films.

Temperature dependent electrical properties of thermoplastic polypropylene nanocomposites for HVDC cable insulation

Polypropylene has been regarded as a potential recyclable insulation material for HVDC cable, which is beneficial to improve the working temperature and transmission capacity of HVDC cables. However, the electrical properties of polymeric insulation materials exhibit apparent temperature dependent characteristics. Temperature influences the generation and migration of charge carriers, thereby affecting the electrical properties. This paper focuses on the electrical properties of polypropylene nanocomposites at different temperatures, including volume resistivity, space charge and DC breakdown strength. The temperature dependent electrical properties of polypropylene are regulated by adding MgO nanoparticles. Based on the characterization of microstructure and trap characteristics, the mechanism of regulating the charge carrier transport process and the electrical properties of the nanocomposites by introducing MgO nanoparticles is explained. The polypropylene nanocomposites show decreased electrical conduction, suppressed space charge accumulation and increased DC breakdown strength, which are desirable for recyclable HVDC cable insulation application. This work may pave a way for tailoring the high temperature electrical properties of polymeric insulation material.

Growth and optoelectronic properties of Cu3NPdx thin films by solution deposition

Cu3NPdx thin films have been successfully prepared on glass substrates by a facile chemical solution deposition. Phase composition and surface morphology are evaluated by X-ray diffraction and field-emission scanning electronic microscope. The X-ray diffraction and X-ray photoelectron spectroscopy results reveal that palladium will occupy the body centre position. Pd dependent electrical and optical properties of the Cu3NPdx thin films are investigated. Electrical conductivity can be greatly improved and the indirect bandgap is decreased with increasing the palladium doping, and the optical band gap can be adjusted within the range of 1.40–1.04 eV. The results will provide a facile solution route to synthesize high-quality copper nitride thin films with low-cost and controllable optoelectronic performance.

Bi(Zn0.5Ti0.5)O3 induced domain evolution and its effect on electrical property and thermal stability of 0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3 ceramics

0.8Na0.5Bi0.5TiO3-(0.2-x)K0.5Bi0.5TiO3-xBi(Zn0.5Ti0.5)O3 (NBT-KBT-BZT, x = 0–0.05 with interval of 0.01) lead-free piezoceramics were prepared and investigated. The addition of BZT has not led to deviation of rhombohedral-tetragonal morphotropic phase boundary, but apparently composition-dependent electrical property and monotonously improved thermal stability. The x = 0.02 has the optimal electrical property with remnant polarization, bipolar total strain, piezoelectric constant of 26.5 μC/cm2, 0.30%, 121 pC/N respectively, while the depolarization temperature is increased from 93 °C for x = 0–135 °C for x = 0.05 based on dielectric measurement. Detailed investigation reveals that the domain structure transforms from labyrinthian domain for x = 0 to coexistence of nanodomain and labyrinthian domain for x = 0.02, end up with large amount of nanodomain (x = 0.04). Such domain evolution should be responsible for the composition dependent electrical property and improved thermal stability. Our work confirms that domain engineering is an alternative method to develop high performance piezoelectric materials.

Broad range frequency – temperature response of Ba2Zn2Fe12O22

Ba2Zn2Fe12O22 was synthesized by solid state reaction technique. The temperature and frequency dependent electrical properties and complex impedance spectroscopy were analysed. Complex modulus formalism shows the existence of high resistance and small capacitance of the material for the short range relaxation. The presence of non-Debye type relaxation is revealed from Nyquist plots and enabled to separate the contribution from bulk and grain boundary effect in the material. Further, the ac electrical conductivity of the material was well agreed with the Jonscher's universal power law.

Hydrothermal Growth and Humidity-Dependent Electrical Properties of Molybdenum Disulphide Nanosheets.

In present investigation, we report humidity dependent electrical properties of molybdenum disulphide (MoS₂) nanosheets. MoS₂ nanosheets were prepared through a facile hydrothermal method with different reaction temperatures. The as-synthesized MoS₂ nanosheets were characterized with XRD, SEM, TEM, and Raman spectroscopy, which confirmed successful preparation and rationality. Further, the humidity dependent electrical properties against relative humidity (RH) of these samples were carried out at room temperature. The results evinced that the sensors film fabricated with MoS₂ nanosheets prepared at temperature 220 °C exhibited better performance compared to the nanosheets synthesized at 180 °C and 200 °C temperature. The RH sensing results exhibits highly sensitive, ultrafast response/recovery behaviour and outstanding repeatability than reported earlier. The excellent humidity sensing properties of the resultant MoS₂ nanosheets was proved to be an excellent candidate for constructing ultrahigh-performance humidity sensor toward various applications.

Impact of PVDF/PEO blend composition on the β-phase crystallization and dielectric properties of silica nanoparticles incorporated polymer nanocomposites

Polymer nanocomposite (PNC) films consisted of varying weight composition polymer blends of poly(vinylidene fluoride) (PVDF) and poly(ethylene oxide) (PEO) as host organic matrices incorporated with 5 wt% amorphous silica (SiO2) nanoparticles as inorganic nanofiller have been prepared by solution casting method. The alterations in morphology, PVDF polymorphism and relative fraction of β-phase crystals, degree of crystallinity, and the polymer-polymer and polymer-nanoparticle interactions with change of polymer blend compositional weight ratio (i.e., PVDF/PEO = 100/0, 75/25, 50/50, 25/75, and 0/100) have been investigated by the SEM, EDX, XRD, and FTIR measurements. The frequency dependent complex dielectric permittivity, ac electrical conductivity, and electric modulus of the PNC films are studied at room temperature by employing the DRS technique. The SEM images reveal that the spherulite morphology of PVDF/PEO blend structures incorporated with SiO2 nanoparticles is altered enormously with the change of polymers blend compositions in the PNC films. The XRD results of these PNC films confirm that the β-phase crystallization is considerably enhanced in the PVDF-rich PNC film but it decreases almost linearly with the increase of PEO amount in the host matrices of these films, and remains higher for the PNC films in comparison to that of the pristine polymer blend films. The degree of crystallinity of these PNC films enhances non-linearly with the increase of PEO concentration but it is found low as compared to that of the PVDF/PEO blend films without nanofiller. Dielectric dispersion in the frequency range from 20 Hz to1 MHz reveals that the interfacial polarization significantly contributed to the enhancement of dielectric permittivity in the audio frequency range of dielectric spectra of these PNC films. The addition of 5 wt% amount of SiO2 nanoparticles in the pristine PVDF and PEO matrices reduces the dielectric permittivity over the entire frequency range, whereas the presence of these nanofiller particles in the PVDF/PEO blend matrices based PNC films increases at radio frequencies which is predominantly due to enhancement of the β-phase crystals. The relaxation time values determined from the relaxation peaks exhibited in the loss part of electric modulus spectra confirm that there is an increase in hindrance to the PEO chain segmental dynamics with the increase of PVDF amount in the polymer blend compositions of these PNC films, whereas the dc electrical conductivity is found independent of the blend composition. The polymer blend compositional ratio dependent promising structural, dielectric, and electrical properties of these PNC films offer their suitability as tunable novel nanodielectric materials of multifunctionality for the flexible electronic devices.

Frequency and temperature dependent intrinsic electric properties of manganese doped cobalt ferrite nanoparticles

This paper reports a series of investigations on the frequency and temperature dependent intrinsic electric properties of manganese doped cobalt ferrite nanoparticles. The investigated samples were prepared via solid state reaction route using the planetary ball milling technique. The XRD patterns confirm their crystallinity and single phase spinel structure. The Field Emission Electron Scanning Microscopic (FE-SEM) micrographs show the agglomerated particle with a nearly spherical shape. The estimated lattice constant is found to decrease but the crystallites size to increase with the Mn content. The ac resistivity is found to decrease exponentially with the increase of frequency due to the effect of multilayer capacitance. Conversely, the ac conductivity is observed to increase exponentially with the frequency due to increased hopping between metallic cationsFe2+and Fe3+. The temperature dependent ac resistivity exhibits the semiconducting behavior of the materials above room temperature. The variation in both the resistivity and conductivity is assumed to follow the Arrhenius equation at a selected frequency of 10 kHz. The estimated activation energy using the Arrhenius equation of ac conductivity in the ferro region is found to increase with the Mn content. This increasing trend in activation energy signifies ferrimagnetic-to-paramagnetic phase transition. Besides, the electric modulus shows the contributions of both the grain and grain boundaries to the conduction mechanism in the materials. This nature of temperature dependent resistivity is as usual for the majority of nanoferrite materials.

Prototype of a measurement device for frequency dependent soil electrical properties

Studies show that grounding potential rise and lightning performance of transmission lines are significantly influenced by frequency dependent soil properties (resistivity and permittivity). In order to perform calculations of the transient grounding characteristics more accurately, additional experimental data for different soils is needed. Currently, field measurements of the frequency dependent soil properties can take a significant amount of time. This limits the amount of available experimental data. Thus, for conducting a large number of measurements, a convenient measurement device is needed. Several parameters of the measurement device for the frequency dependent soil electrical properties are discussed in the article (such as preferable generated waveform, the amplitude of the signal, input impedance of the voltage measurement probe, isolation between measurement circuits), and a prototype of the device is presented. A critically important factor for this kind of measurements is high impedance between the current and voltage measurement circuits. In order to achieve proper isolation between the circuits, the optically-isolated probe was made for the voltage measurements. An example of measurements with the dipole-dipole electrode array for high-resistivity soil is presented. Further improvements for the measurement device are also suggested in the article. With these improvements, the measurements can be almost as fast and simple as those made with a conventional soil resistivity meter.

Co effect on the structural, chemical and frequency depended electrical properties of YbFeO3 perovskite oxide compound

We have synthesized YbFe1−xCoxO3 (x = 0, 0.01, 0.05, 0.10) compounds by the conventional solid-state method. Structural and chemical analysis of the synthesized compounds have been carried out by XPS, SEM and EDX techniques. Frequency dependent (1–107 Hz) electrical properties including the loss tangent, real and imaginary part of impedance and resistivity have been examined in wide range temperature (from − 100 to 100 °C with 20 °C step) using Dielectric/Impedance Spectrometer (Novocontrol). The frequency dependent loss tangent plots have showed different dielectric relaxations peaks and the activation energies of the compounds have been calculated from those peaks using Arrhenius relation. The resistivity measurement results revealed that the increasing Co doping ratio decreases the resistivity of the compounds.

Dielectric and impedance spectroscopic study of lithium doped potassium tantalum niobium oxide

Abstract The (K0.90Li0.10) (Nb0.80Ta0.20)0.99Mn0.01O3 (KLTN) ceramic has been synthesized by the conventional solid-state reaction route. The Rietveld refinement X-Ray diffraction (XRD) patterns confirmed the single-phase orthorhombic crystal structure with space group Amm2. The frequency dependent electrical properties were examined by the complex dielectric and impedance spectroscopy in the temperature range 30 °C–500 °C where multiple structural phase transition was observed with high dielectric constant, low tangent loss and well saturated electric polarization. The shifting of the ferroelectric phase transition temperature by 30 °C in heating and cooling mode suggests the irreversible motion of the domains and domain walls and significant effects on grain boundaries on structural phase transition temperature. A series of phase transitions from orthorhombic to tetragonal (∼190 °C) and tetragonal to Cubic (∼390 °C in cooling and 420 °C in heating) have been obtained in the wide range of temperature. The different type of analogy such as Modulus formalism, complex impedance spectra, frequency dependent conductivity, the activation energy of charge carriers has been used to understand the microstructure-electrical properties relation.

Optically tunable magnetoelectric properties of inorganic-organic multiferroic flexible film

Magnetoelectric composites are promising materials for their physical properties such as spontaneous electrical polarization or magnetization with the application of magnetic or electric field. In addition, Spinel ferrite based magnetoelectric composite materials absorb a range of light energy, which offers a lot of physical phenomena behind the light-dependent magnetoelectric properties of the composite. The piezoelectric organic polymer based magnetoelectric composite of Zn0.2Co0.8Fe2O4-poly(vinylidene fluoride) flexible film has been fabricated by a chemical pyrophoric reaction process followed by a solution casting process. Structural and surface morphologies of the composite film have been studied. The visible light and applied magnetic field dependent AC electrical properties of the composite flexible film have been investigated at room temperature which reveals that the maximum change in impedance is found to be ∼10% and ∼20%, respectively. However, with an influence of both the light and the magnetic field, the impedance of the composite film is largely changed attributing that the excited electron may get a low resistive path through the grain and grain boundaries where the maximum change in impedance is found to be ∼30%. This result further is confirmed from the change of grain and grain boundary resistance and capacitance through the fitting of Nyquist plots. The present work provides information about the optically and magnetically influenced physical properties of the composite flexible film, which will be expanded for multiferroic magnetoelectric device applications.

Morphology dependent electrical property of chitosan film and modeling by fractal theory

The present study proposes a more general fractal approach-iterated function system (IFS) model for explaining the morphology of a biopolymer like chitosan dissolved in various organic acids and forming film and compared with the experimental results through multifractal approach. The bio polymer like chitosan has been dissolved in various organic acids like formic, acetic, adipic and the film of the same also have been formed through solution casting technique. The morphology of the prepared films have been obtained from scanning electron microscope (SEM) and the electrical impedance from LCR HIOKI Hi-Tester. The IFS theory is used to generate the morphology of chitosan film dissolved in various organic acids of various concentrations. In order to draw the similarity between morphological structure of experimentally obtained self-similar property of chitosan dissolved in various acids of different concentration of chitosan and the same has been generated by random iterated algorithm. The generalized fractal dimensions are estimated and compared with the electrical property like impedance which follows the same trend. Further, the growth of bacterial colonies and its self-similar structure has been generated by the same method. Hence it is inferred that our model is a more general model for the generation of self-similar property exhibited by nature.

Spin and charge state dependent electrical and magnetic properties of diamond with defects of vacancy and substituted silicon by first-principles calculation

In this work, the electrical and magnetic properties of diamond crystals with defects of substituted silicon (SiC), vacancy (VC), Si-vacancy (SiV), and Si-divacancy (SiV2) complexes are investigated by first-principles calculations considering the spin and charge state. For the cases of VC, SiV, and SiV2, the typical spin-splitting related defect levels are presented in the bandgap, mainly stemming from the dangling bonds surrounding the vacancies. The magnetic moments appear for the cases of neutral (VC0 and SiV0) and negatively charged (VC−, SiV−, and SiV2−) defects, determined by the occupied spin states and defect configurations. It reveals that the charge state plays an important role in modulating the magnetic moments and energy splitting of defect levels in diamond. This work provides theoretical guidance for achieving a class of spin-related diamond semiconductor devices.

Frequency and voltage dependent electrical and dielectric properties of Ag/nGO doped PVA/p-Si sandwich structure at room temperature

In present study, we investigated frequency and voltage dependence of electrical and dielectric properties of Ag/nGO doped poly(vinyl alcohol) (PVA)/ p-Si structures. The nGO-PVA films were prepared by using improved Hummers method and this thin film layers were analyzed with SEM and EDX. The main parameters as ideality factor (n), barrier height (Φbo) and saturation current (I0) were obtained from current–voltage (I-V) measurements. The frequency dependent electrical characteristics of structure investigated using capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements in the frequency range of 10 kHz to 1000 kHz in 300 K absolute temperature. The capacitance, conductance and series resistance (RS) values decreased with increasing frequency. These decreases at higher frequencies are attributed to existence of interface state densities. The presence of the interface state densities (NSS) are also evidenced as a peak in the capacitance, conductance and series resistance–frequency characteristics. After, the dielectric properties of Ag/GO-PVA/ p-Si structures were obtained using C–V and G/ω–V measurements in the same frequency ranges. The values of dielectric constant (ε′), dielectric loss (ε″), and loss tangent (tanδ) decreases with increasing frequency while ac electrical conductivity (σac) increase with increasing frequency. Our results showed that frequency dependent electrical and dielectric properties were strongly frequency and voltage dependent.