Application Of Electric Field Research Articles

Charge Accumulation Dependence on Electric Field, Temperature, and Voltage Application Time in Polymeric Insulating Materials by Current-Integrated Charge Method

Charge Accumulation Dependence on Electric Field, Temperature, and Voltage Application Time in Polymeric Insulating Materials by Current-Integrated Charge Method

Development of ferroelectricity with crystallographic phase transformation in Hf0.5Zr0.5O2 thin films upon initial stimulation of an electric field exceeding the coercive field

This study demonstrates a drastic transformation of ferroelectricity and crystallographic phase in Hf0.5Zr0.5O2 (HZO) thin films through the first stimulation of an electric field larger than the coercive field in metal-ferroelectric-metal (MFM) capacitors. Initially, capacitance–voltage (C–V) measurements in fresh MFM capacitors with voltage sweep smaller than the coercive field indicated constant capacitance value without hysteresis. Applying the electric field exceeding the coercive field subsequently, the C–V behavior changed to a typical dual-peak ferroelectric feature in positive and negative sweeps. X-ray diffraction analysis of the HZO layers before and after a single electric-field application revealed small-angle shifts in diffraction peaks, confirming a crystallographic phase transformation induced by the single electric-field stimulation exceeding the coercive field. These results suggest a possibility that the first electric field apply initiates development of ferroelectric phase transformation from a non-ferroelectric phase.

Efficiency improvement by using metal–insulator-semiconductor structure in InGaN/GaN micro-light-emitting diodes

InGaN/GaN micro-light-emitting diodes (micro-LEDs) with a metal–insulator-semiconductor (MIS) structure on the sidewall are proposed to improve efficiency. In this MIS structure, a sidewall electrode is deposited on the insulating layer-coated sidewall of the device mesa between a cathode on the bottom and an anode on the top. Electroluminescence (EL) measurements of fabricated devices with a mesa diameter of 10 μm show that the application of negative biases on the sidewall electrode can increase the device external quantum efficiency (EQE). In contrast, the application of positive biases can decrease the EQE. The band structure analysis reveals that the EQE is impacted because the application of sidewall electric fields manipulates the local surface electron density along the mesa sidewall and thus controls surface Shockley–Read–Hall (SRH) recombination. Two suggested strategies, reducing insulator layer thickness and exploring alternative materials, can be implemented to further improve the EQE of MIS micro-LEDs in future fabrication.Graphical

Wetting and evaporation behavior of dilute sodium dodecyl sulfate droplets on soft substrates under a direct current electric field

Wetting and evaporation behavior of dilute sodium dodecyl sulfate (SDS) droplets on planar polydimethylsiloxane (PDMS) surfaces under a direct current (DC) electric field were experimentally investigated. Two characteristic voltages—actuation voltage and saturation voltage were observed in the electrowetting of dilute SDS droplets on PDMS surfaces. It was found that for dilute SDS droplets with a fixed SDS concentration substrate elasticity has an obvious influence on actuation voltage, and saturation voltage increased with the increase of mass ratio of PDMS surfaces. SDS concentration was also found to obviously influence actuation voltage and saturation voltage when SDS concentration was in a certain range. For the case of evaporation of sessile dilute SDS droplets on PDMS surfaces with the application of a DC electric field, substrate elasticity, SDS concentration and the magnitude of applied voltage were all found to have an influence on the duration of CCR stage. Moreover, contact angle hysteresis for dilute SDS droplets on a planar PDMS 10:1 surface under different applied voltage was measured and it was found that the magnitude of applied voltage greatly influenced contact angle hysteresis, which also depends on SDS concentration and KCl concentration.

Dual-frequency-addressable photochromic cholesteric mixture with photo- and electro-switchable optical properties

Cholesteric liquid crystalline mixture with photo-, electro-controllable optical properties was prepared and the features of its switching behavior were demonstrated. The working principle of the obtained switchable cell is based on using dual-frequency-addressable nematic mixture that enables effective control of selectively reflected planar and scattered focal conics texture by applied field frequency modulation. The nematic mixture was doped with the chiral substance in order to induce a cholesteric structure formation with selective light reflection in visible spectral range. Azobenzene-containing photochrome was also introduced into this mixture in order to stimulate photo-optical response. An application of low-frequency electric field as well as UV irradiation induces short-wavelength shift of the selective light reflection. Under action of an electric field, a transition to scattered focal conics texture takes place. Amplitude of the light-induced shift is ca. 50 nm, while the electric field leads to a shift ca. 120 nm. On the contrary, high-frequency electric field induces fast (less than 1 s) restoration of perfect highly reflected planar texture. UV irradiation leads to not only shift of the selective light reflection band, but alters the electrooptic response by increase of frequency necessary for the restoration of the planar state and considerably changes the switching kinetics. The possibility of photopatterning of the obtained electrooptic cells by UV irradiation through a mask is demonstrated. It is shown, that application of electric field of different strength and frequencies enables smart control of the photorecorded image contrast.

Fast Fabrication Nanopores on a PMMA Membrane by a Local High Electric Field Controlled Breakdown.

The sensitivity and accuracy of nanopore sensors are severely hindered by the high noise associated with solid-state nanopores. To mitigate this issue, the deposition of organic polymer materials onto silicon nitride (SiNx) membranes has been effective in obtaining low-noise measurements. Nonetheless, the fabrication of nanopores sub-10 nm on thin polymer membranes remains a significant challenge. This work proposes a method for fabricating nanopores on polymethyl methacrylate (PMMA) membrane by the local high electrical field controlled breakdown, exploring the impact of voltage and current on the breakdown of PMMA membranes and discussing the mechanism underlying the breakdown voltage and current during the formation of nanopores. By improving the electric field application method, transient high electric fields that are one-seven times higher than the breakdown electric field can be utilized to fabricate nanopores. A comparative analysis was performed on the current noise levels of nanopores in PMMA-SiNx composite membranes and SiNx nanopores with a 5 nm diameter. The results demonstrated that the fast fabrication of nanopores on PMMA-SiNx membranes exhibited reduced current noise compared to SiNx nanopores. This finding provides evidence supporting the feasibility of utilizing this technology for efficiently fabricating low-noise nanopores on polymer composite membranes.

Tuning optical properties of Au thin film using electric field for surface plasmon resonance biosensor application

The effect of electric field application on the optical properties of gold (Au) thin film for spectroscopic ellipsometry-based surface plasmon resonance (SPR) biosensor applications has been successfully studied. The optical properties, such as the complex refractive index, complex dielectric constant, real optical conductivity, and absorption coefficient, were determined by fitting data from the ψ and Δ functions obtained through measurements using a homemade rotating analyzer ellipsometer. The applied electric fields of 0.8 V/cm, 1.6 V/cm, 2.4 V/cm, and 3.2 V/cm were induced by applying voltages of 1 V, 2 V, 3 V, and 4 V for ellipsometer tests, and 1.6 V/cm to 3.2 V/cm for the SPR test. The Au thin film was deposited onto a glass slide using an evaporator for ellipsometer testing and a BK7 half-cylinder prism was employed for SPR testing. The experimental results show that the real part of the refractive index (n) increases in the spectral range from 1.5 eV to 2.2 eV and from 3 eV to 5 eV and tends to be constant in the range from 2.3 eV to 2.8 eV. Conversely, the imaginary part of the refractive index (k) decreases from 2.8 eV to 3.6 eV and tends to remain consistent from 3.9 eV to 5.0 eV. The dielectric constant (ε1) consistently shows a significant increase within the spectral range of 3 eV–5.0 eV, with a tendency to decrease between 2.1 eV and 2.4 eV. Meanwhile, the imaginary part (ε2) demonstrates an increase in the spectral range of 1.5 eV–2.4 eV and 3.3 eV–5.0 eV while maintaining relatively stable values in the energy spectral range of 2.6 eV–3.0 eV. Moving to the real part of optical conductivity (σ1), it increases within the spectral range from 1.5 eV to 2.4 eV and from 3.5 eV to 5 eV, with relatively constant values between 2.6 eV and 3.1 eV. The absorption coefficient (α) exhibits a decrease in the spectrum between 2.8 eV and 3.6 eV, but the values remain stable within the range of 3.9 eV–5.0 eV. The α slightly decreases in the energy range of 1.8 eV–2.6 eV. The outcomes obtained from these experiments are directly linked to the SPR results, revealing a noticeable shift in the SPR angle (θSPR) of 45.51°, 45.61°, and 45.73° and an increase in the minimum reflectance (Rmin) of 0.05, 0.09, and 0.13 for electric field strengths of 0 V/cm, 1.6 V/cm, and 3.2 V/cm, respectively. These results imply that the application of an external electric field to the surface of the Au thin film disrupts the matching condition between the evanescent wave vector and the surface plasmon wave vector, thereby altering the reflected light under resonance conditions indicated by an increase in the minimum reflectance and SPR angle. This development holds significant promise to further enhance the sensitivity of electro-optic modulation-based biosensors.

External electric field assisted energy band gap modulation and optical properties of SiGe/AsSb heterobilayers

In this work, first-principle calculations within Density Functional Theory (DFT) were performed to study the structural, electronic, and optical properties of eight different bilayer van der Waals (vdW) heterostructures composed of SiGe and AsSb monolayers. These heterobilayers exhibit large energy bandgap (90 meV–459 meV) with linear energy–momentum relationship, implying high charge carrier mobility. Application of external vertical electric field can effectively modulate the energy bandgap of these heterobilayers from 64 meV to 459 meV, depending on stacking orders. Our study shows that a moderate amount of electric field can almost linearly tune the energy bandgap, however, semiconductor to metal transition occurs beyond a certain limit. The mechanism of energy bandgap tuning by the external electric field was examined by studying differential charge density. The optical properties such as complex dielectric function, electron energy loss function, complex refractive index, reflectivity, absorption coefficient, and optical conductivity of these SiGe/AsSb heterobilayers are studied for parallelly and perpendicularly polarized incident light. Our research demonstrates that these heterostructures exhibit variable plasma frequency depending on the stacking order of the heterostructures, anisotropic reflectivity i.e., birefringence properties in response to the incident light's polarization. Also, they exhibit high refractive indices (∼3) and absorption coefficients (∼105 cm−1) from visible to ultraviolet incident light frequencies. Our study proposes several SiGe/AsSb heterobilayers with unique electronic and optical properties which may have potential applications in nanoscale electronic and optoelectronic applications.

Reversible nanocracks-induced resistive switching manipulated by ferroelectric polarizing in Te/PMN-PT heterostructures

Ferroelectricity-based storage technology is anticipated to achieve nonvolatile, low-power, and high-density storage in integrated field circuits. Here, the phenomena of electrically reversible switching of nanocracks in the tellurium film/ferroelectric PMN-PT heterojunctions are discussed. Upon the application of external electric fields (±2 kV/cm), the nonvolatile resistance on-off ratio reached over 106 at room temperature. This was achieved through the opening and closing of cracks in the Te film caused by the electric-field-driven flipping of 109° ferroelectric domains in a ferroelectric single crystal. In addition, the ON/OFF resistance states remain stable even after more than 103 cycles and the retention time exceeds 6 h, demonstrating excellent fatigue resistance performance of the device. This work renders a window to design nonvolatile memory by constructing electric-field tunable nanocracks in a semiconductor film/ferroelectrics heterojunction system.

Extraction efficacy of newly designed electric fields on red beetroot samples

A newly designed voltage treatment chamber for AC electric field application with high voltage transformer, voltage divider, over current limiter, and vacuum treatment chamber was utilized to treat red beetroot samples by 0.00–11.5 kV, 400–1013 mbar, and 18.15–20.00min. Applied processing parameters caused a significant increase in the total antioxidant capacity. The best-fit multiple (non-) linear regression models with response optimization revealed 4.6 kV, 400 mbar, and 30.90% moisture as the most optimal processing parameters with 0.8313 composite desirability. Application of electric fields may be utilized for the electroporation of the plant tissue without adverse effect on important properties.

On-Surface Fabrication toward Polar 2D Macromolecular Crystals.

Polar 2D macromolecular structures have attracted significant attention because of their ferroelectricity and ferro-magnetism. However, it is challenging to synthesize them experimentally because dipoles or spins of these macromolecules tend to cancel each other. So far, there has been no successful strategy for assembling macromolecules in a unidirectional manner, achieving stereoregular polymerization on metal surfaces, and creating polar 2D polymer crystals. Recent progress in molecular assembly, on-surface polymer synthesis, and direct control of molecules using electric field applications provides an opportunity to develop such strategies. In this regard, we first review past studies on chiral and achiral molecular assembly, on-surface polymer synthesis, and orientation control of polar molecules. Then, we discuss our newly developed approach called "vectorial on-surface synthesis", which is based on "dynamic chirality" of compass precursors, stereoselective polymerization, and favorable interchain interactions originating from CH-π interactions. Finally, we conclude with a prospective outlook.

Germination and stress tolerance of oats treated with pulsed electric field at different phases of seedling growth

This study explores the impact of pulsed electric field (PEF) application on oat seedling growth and stress tolerance. PEF treatment (99 monopolar, rectangular pulses lasting 10 µs each, with a frequency of 13 Hz and a nominal electric field strength of 2250 V/cm) was applied at two growth stages: (i) when the seedlings had 0.2 cm roots emerging from the kernel, and (ii) when they had a 0.4 cm shoot emerging from the kernel. Post-treatment, the seedlings were hydroponically grown for 8 days. To induce stress, the hydroponic medium was augmented with PEG (15 %) to induce drought stress and NaCl (150 mM) to induce salinity stress. Results demonstrate that applying PEF improved the growth of the root and shoot of oat seedlings. This effect was more pronounced when applied to more developed seedlings. When PEF was applied during the later stage of germination, seedlings exposed to salinity stress showed enhanced shoot growth compared to the control. Under the studied conditions, the application of PEF had no impact on the growth of seedlings under drought stress.

Reversible charge injection in artificially created charged domain wall region

The impact of electric field application in the charged domain wall (DW) region on the performance of DW devices remains elusive. Here, we present our observations of substantial charge injection occurring in an artificially created charged DW region. Rapid charge injection coincides with polarization switching, contributing to the transient current collected for the integration of polarization-voltage hysteresis loops. Subsequently, a gradual injection of charges persists under externally applied voltages, diffusing into the thin film from the DW region to screen the space defect dipoles and effectively suppressing the imprint field. The process of charge injection proves reversible and is notably more pronounced in aged ferroelectric thin films, as evidenced in planar BiFeO3 nanodevices where the charge injection amount is five orders of magnitude higher than charges generated from polarization switching. This work constitutes a significant contribution to understanding the intricate process of charge injection and its influence on charged DW.

Adsorption of CO, CO2 and NO2 molecules on Li/Pt decorated C-57 nanostructures and effect of applied external electric field: A DFT study

The adsorption behavior of CO2, NO2, and CO gasses on C-57 carbon nanotubes is presently being investigated in this work. Utilizing density functional theory (DFT) computations at the vdW-DF3-OPT2 and PBEsol theoretical levels, the adsorption characteristics of these gases on Li-decorated nanostructures are being investigated. This article examines the NEB (Nudged Elastic Band) technique for gas adsorption on carbon nanotubes. The results of the study can help with the development and improvement of gas adsorption systems based on carbon nanotubes. Furthermore, at various strengths of external electrical fields, the adsorption behavior of CO2 and CO gasses on Pt-decorated C-57 carbon nanosheets is being investigated. The findings provide insights into how the electric field affects the adsorption energy. The objective of this study is to further our knowledge of gas adsorption on C-57 carbon nanostructures and to demonstrate how external electric fields can be used to modify the adsorption properties for a range of energy and environmental applications. We are currently studying the geometries of 1 up to 2 adsorbed gas molecules on the exterior of the nanotube and identifying preferred Li-decorated sites in terms of gas adsorption energy. The charge density difference and electronic band structures are currently being used to assess the adsorption system's characteristics. The charge accumulation between the interacting atoms is being revealed by charge density difference calculations, suggesting the possibility of covalent bond formation. This nanostructure may make a good material for gas adsorption, according to the adsorption energy data (-0.4 to 1.6 (eV)). The efficiency of gas capture and storage systems can be improved by varying the adsorption behavior through the application of an external electrical field.

Time-dependent model of temperature distribution in continuous flow pulsed electric field treatment chambers

A key component of a continuous flow pulsed electric field (PEF) system is the treatment chamber, where the product is exposed to electric pulses. Determination of the temperature distribution in the chamber during PEF treatment is important since high local increases in temperatures can affect the quality of the product. Coupled simulations of electric field, fluid flow, and heating in the existing literature do not model each individual electric pulse, but rather employ a “duty cycle” approach, which does not account for transient variations in treatment intensity and temperature changes in the medium. We present a time-dependent approach to modelling PEF treatment in continuous flow treatment chambers, which can model each pulse separately, and thus enables a more accurate study of temporal and spatial distributions of electric field and temperature. The model has been validated on laboratory scale treatment chambers of parallel plate or colinear design and using realistic protocols. Industrial relevance textThe paper is relevant to all pulsed electric field (PEF) applications either on laboratory or industrial scale that implement a continuous flow treatment chamber. It presents an improved modelling approach which allows for an analysis of the electrical current, electric field, and temperature distribution in the chamber during, at the end, and in between application of electrical pulses. The model can be used to predict the peak temperature at the end of each pulse in the hot spots, which if large enough could potentially lead to thermal damage of the product or in extreme cases even potential local boiling of the medium, resulting not only in degradation of the treated product, but also in accelerated electrode fouling, oxidation, and dissolution (etching), as well as arcing. This would not only affect the quality of the treated product but would also affect the wear and lifetime of electrodes/chambers, and of the pulse generator. The model can also be used to avoid expensive trial-and-error optimization of the PEF protocols and chamber geometries in situ.

Field-free control and switching of perpendicular magnetization by voltage induced manipulation of RKKY interaction

Voltage control of magnetization offers substantial advantages in energy efficiency for the development of spintronics technology. However, achieving a complete 180° magnetization switching remains as a challenging task since the electric field cannot provide torques to turn the magnetic moment in the ferromagnetic material. To address this challenge, we explore the utilization of synthetic antiferromagnetic (sAFM) structure coupled by Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction in the two ferromagnetic (FM) Co layers separated by a suitable thickness Ru spacer layer. One of the FM layers was prepared to be in contact with the GdOx layer, where ionic motion of oxygen can be manipulated via an application of electric field. Depending on the oxidation state at the interface with GdOx, the RKKY coupling can be adjusted and achieves reversible transitions between antiferromagnetic (AFM) and FM orders of FM layers at room temperature. The transition is mediated by the migration and redistribution of oxygen ions, transforming the Co/Gd interface into Co/GdOx and vice versa. This method suggests a stable and electrical route for magnetization reversals without an external magnetic field.

First-principles study on the effects of fast neutron irradiation and fast neutron irradiation under the external electric field on carbon-based material AB bilayer graphene

The irradiation damage mechanism of fast neutron irradiation and the fast neutron irradiation under the practical application of an additional electric field on carbon-based material AB bilayer graphene is not yet clear. This paper systematically investigates the impact of fast neutron irradiation and fast neutron irradiation under the practical application of the additional electric field (−0.2 V/Å) on carbon-based material AB bilayer graphene through density functional theory and molecular dynamics simulations. The research results indicate that the changes in the configuration of AB bilayer graphene and the appearance of surface ripples induced by fast neutron irradiation are the two main reasons for the alterations in the system's microstructure, band structure, Young's modulus, and optical properties, which may lead to performance degradation and damage of carbon-based devices. The further variation in the average interlayer spacing of the system under external electric field irradiation leads to the diversity of the system configuration, which ultimately leads to the diversity of the band structure of the system. The uncertainty in the type and width of the bandgap in AB bilayer graphene under fast neutron irradiation with an external electric field may be one of the reasons for the performance degradation and permanent damage of carbon based devices in practical applications. In the fast neutron irradiation environment, the precise control of the bandgap of AB bilayer graphene by an applied electric field will fail.

Applied electric field to repair metal defects and accelerate dehydrogenation

Repairing metal micro-defects at the atomic level is very challenging due to their random dispersion and difficulty in identification. At the same time, the interaction of hydrogen with metal may cause hydrogen damage or embrittlement, endangering structural safety. As a result, it is critical to speed up the dehydrogenation of hydrogen-containing materials. The applied electric field can repair the vacancy defects of the material and accelerate the dehydrogenation of the hydrogen-containing metal. The influence of the external environment on the diffusion coefficient of hydrogen in polycrystalline metals was researched using molecular dynamics in this article, and the mechanism of hydrogen diffusion was investigated. Simultaneously, the mechanical characteristics of Fe3Cr alloy were compared during typical heat treatment and electrical treatment. The effect of temperature, electric field strength, and electric field direction on the diffusion coefficient was investigated using orthogonal test analysis. The results demonstrate that temperature and electric field strength have a significant impact on the diffusion coefficient. The atom vibrates violently as the temperature rises, breaking past the diffusion barrier and completing the atomic transition. The addition of the electric field adds extra free energy, decreases the atom’s activation energy, and ultimately enhances the atom’s diffusion coefficient. The repair impact of vacancy defects under electrical treatment is superior to that of typical annealing treatment for polycrystalline Fe3Cr alloy. The electric field can cause the dislocation to migrate, increasing the metal’s toughness and plasticity. This research serves as a useful reference for the electrical treatment of metal materials and offers a method for the quick dehydrogenation of hydrogen-containing materials.

Can rare earth elements be recovered from abandoned mine tailings by means of electrokinetic-assisted phytoextraction?

Given the high impact of traditional mining, the recovery of rare earth elements (REEs) from hazardous waste materials could become an option for the future in accordance with the principles of the circular economy. In this work, the technical feasibility of REEs recovery from metal mine tailings has been explored using electrokinetic-assisted phytoremediation with ryegrass (Lolium perenne L.). Phytoextraction combined with both AC current and DC current with reversal polarity was applied (1 V cm−1, 8 h day−1) to real mine tailings containing a total concentration of REEs (Sc, Y, La, Ce, Pr, and Nd) of around 146 mg kg−1. Changes in REEs geochemical fractionation and their concentrations in the soil pore water showed the mobilization of REEs caused by plants and electric current; REE availability was increased to a higher extent for combined electrokinetic-assisted phytoextraction treatments showing the relevant role of plants in the process. Our results demonstrated the initial hypothesis that it is feasible to recover REEs from real metal mining waste by phytoextraction and that the performance of this technology can be significantly improved by applying electric current, especially of the AC type, which increased REE accumulation in ryegrass in the range 57–68% as compared to that of the treatment without electric field application.

Superior nanocomposites of phosphonium-based poly(ionic liquid) with halloysite and graphene oxide: Electrorheological investigations

Phosphonium-based poly(ionic liquid) (PPIL) as well as its nanocomposites with halloysite (HNT) and graphene oxide (GO) were synthesized in this study. PPIL structure was engineered to be poly[(4-vinylbenzyl) trimethyl phosphonium trifluoromethane sulfonate] for high electrorheological (ER) performance. To improve ER properties of PPIL, HNT clay with strong mechanical, thermal, and insulating properties and GO with strong dielectric properties were introduced into the PPIL structure by covalent bonding. The synergistic electroactive effect of HNT and GO in the hybrid nanocomposites were investigated by comparing PPIL, HNT/PPIL and HNT/GO/PPIL structures. Structural, thermal, and morphological characterizations approved the successful synthesis of samples. Dielectric and ER flow tests of dispersions of the engineered structures in insulating silicone oil (SO) indicated that PPIL (Δε′ = 1.80 and τy = 250 Pa, EReff = 35, G′ = 33 kPa at 2.0 kV mm-1) and HNT/PPIL (Δε′ = 1.55 and τy = 260 Pa, EReff = 51, G′ = 100 kPa at 2.0 kV mm-1) have similar electroactive properties whereas the highest polarizability and ER response are achieved with HNT/GO/PPIL hybrid nanocomposite (Δε′ = 2.50 and τy = 410 Pa, EReff = 67, G′ = 790 kPa at 2.0 kV mm-1). The findings indicated that electrical stability and electric field induced polarizability of PPIL have been improved by the presence of HNT and GO, respectively. When compared with the previously reported ER studies for ammonium-based poly(ionic liquid)s, PPIL and its nanocomposites of HNT/PPIL and HNT/GO/PPIL exhibited better ER properties, as projected. The application of electric field resulted in the switchable viscoelastic character for PPIL/SO, HNT/PPIL/SO and HNT/GO/PPIL/SO dispersions. Similar to the ER flow properties, the best electroactive viscoelastic properties were obtained for the dispersion of triple HNT/GO/PPIL hybrid nanocomposite. Overall, new ER dispersions of phosphonium-based poly(ionic liquid) and its superior nanocomposites were introduced to the literature.