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Silicon carbide (SiC) exhibits superior properties, including a wide bandgap, high breakdown electric field, high thermal conductivity, high electron saturation drift velocity, strong radiation resistance, and excellent chemical stability, making it highly suitable for power device applications. In the substrate slicing process for fabricating SiC power devices, pulsed laser technology provides several advantages over traditional diamond wire sawing, including a smaller heat-affected zone, reduced thermal defects, higher precision, and improved efficiency. To gain a deeper understanding of the interaction between femtosecond lasers and 4H-SiC materials at the atomic scale, this study employs real-time time-dependent density functional theory simulations, incorporating carrier cooling to maintain detailed balance. The analysis examines the evolution of carrier number, density of states, Si–C bond length, and atomic disorder over time under photoexcitation at varying wavelengths and intensities. The results indicate that ultrafast non-thermal melting in 4H-SiC arises from carrier localization, which induces uneven interatomic forces, leading to local atomic displacements, which increases atomic bond lengths and ultimately results in melting. Long-wavelength 1064 nm laser irradiation was found to cause greater atomic force imbalances and displacements than shorter wavelengths (266 and 532 nm), leading to more pronounced non-thermal melting. This study provides atomic-scale theoretical support for research on femtosecond laser processing of 4H-SiC ingots and substrates. [ABSTRACT FROM AUTHOR]

The epoxy insulation used in high frequency transformers encountered breakdown easily due to bipolar square wave voltage with steep rising/falling edge and high frequency. An insight into the frequency dependence of electrical tree development in epoxy resin under bipolar square wave voltage was elucidated in this paper. It was found that luminescence existed in all treeing channels, where the intensity of luminescence at the electrical tree tip under a high frequency (>4 kHz) was stronger than that at a low frequency (<4 kHz), indicating an electric field delivery from the needle tip to the channel tip at high frequency. Correspondingly, the fluorescent material deposited on the wall of the tree channel evolved from discontinuous at a low frequency to continuous at a high frequency with aggravated degradation. In addition, the frequency dependence of electrical tree breakdown related to field delivery was revealed. By combining the field delivery along treeing channels and the frequency dependence of the mechanical properties of epoxy resin, the growing model of an electrical tree under bipolar square wave voltage was illustrated elaborately. It was proposed that the dominant factors that drove electrical tree propagation were electric field force at a low frequency and partial discharge at a high frequency, respectively. This work can boost the advancement of polymers, electrical equipment, and power electronics at a high frequency. [ABSTRACT FROM AUTHOR]

Al2O3/ZrO2 (A/Z) layers with embedded Pt nanoparticles (Pt-nps) at the interface of A/Z have been used to create a dielectric film with an enhanced permittivity. The Pt-nps and dielectrics are both grown by the atomic layer deposition process, which is complementary metal–oxide–semiconductor compatible. In order to control the thickness ratio of Pt-nps in the overall dielectrics more easily, the thickness of the ZrO2 layer is changed from 12 to 30 nm with a fixed thickness of 12 nm for Al2O3 and constant growth cycles of 70 for Pt-nps. The results show that the introduction of Pt-nps is beneficial to the enhancement of the dielectric permittivity. As the thickness of ZrO2 is 30 nm, the capacitance density increases from 2.5 to 5.1 fF/μm2 with the addition of Pt-nps, i.e., a doubling of the capacitance density achieved. Additionally, the leakage current at 2 V increases from 1.1 × 10−8 to 1.5 × 10−7 A/cm2. Furthermore, the dielectric breakdown field decreases from 5.4 to 2.7 MV/cm. The electric field distribution simulation and charging–discharging test imply that interfacial polarization is built at the interface of Pt-nps and the dielectric films, which contributes to the dielectric permittivity enhancement, and local electric field increasing in the affinity of Pt-nps gives rise to the deterioration of the leakage current and breakdown electric field. [ABSTRACT FROM AUTHOR]

In ultrawide bandgap (UWBG) nitride and oxide semiconductors, increased bandgap (Eg) correlates with greater ionicity and strong electron–phonon coupling. This limits mobility through phonon scattering, localizes carriers via polarons and self-trapping, broadens optical transitions via dynamic disorder, and modifies the breakdown field. Herein, we use polarized optical transmission spectroscopy from 77 to 633 K to investigate the Urbach energy (Eu) for many orientations of Fe- and Sn-doped β-Ga2O3 bulk crystals. We find Eu values ranging from 60 to 140 meV at 293 K and that static (structural defects plus zero-point phonons) disorder contributes more to Eu than dynamic (finite temperature phonon-induced) disorder. This is evidenced by lack of systematic Eu anisotropy, and Eu correlating more with x-ray diffraction rocking-curve broadening than with Sn-doping. The lowest measured Eu are ∼10× larger than for traditional semiconductors, pointing out that band tail effects need to be carefully considered in these materials for high field electronics. We demonstrate that, because optical transmission through thick samples is sensitive to sub-gap absorption, the commonly used Tauc extraction of a bandgap from transmission through Ga2O3 >1–3 μm thick is subject to errors. Combining our Eu(T) from Fe-doped samples with Eg(T) from ellipsometry, we extract a measure of an effective electron–phonon coupling that increases in weighted second order deformation potential with temperature and a larger value for E||b than E||c. The large electron–phonon coupling in β-Ga2O3 suggests that theories of electrical breakdown for traditional semiconductors need expansion to account not just for lower scattering time but also for impact ionization thresholds fluctuating in both time and space. [ABSTRACT FROM AUTHOR]

The unique ability of ferroelectrics to generate high voltage under shock loading is limited by electrical breakdown within the shock-compressed ferroelectric material. Breakdown is a hybrid process of initiation and growth. The possible mechanisms of electrical breakdown in ferroelectric films and bulk ceramics subjected to high-pressure shock loading are discussed and experiments designed to elucidate which mechanisms govern breakdown. Gigapascal shock loading experiments were performed on poled Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ferroelectric film specimens in the range of 32–156 μm thickness to determine the dependence of the breakdown field on thickness and on film specimens in the range of 4–16 mm length to determine the dependence of the breakdown field on the duration of shock compression. The resulting breakdown-field vs thickness and breakdown-field vs shock transit time dependencies are consistent with a hybrid electron emission initiation and Joule heating microchannel growth mechanism. Further analysis of data previously obtained on shock-compressed 0.27Pb(In1/2Nb1/2)O3–0.47Pb(Mg1/3Nb2/3)O3–0.26PbTiO3 ferrvoelectric single crystals and Pb(Zr0.65Ti0.35)O3, Pb0.99(Zr0.52Ti0.48)0.99Nb0.01O3, Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 bulk ceramics is consistent with this dual mechanism. It appears that neither chemical composition nor microstructure (single crystal vs polycrystalline) of the ferroelectric material has a significant effect on the breakdown mechanism in shocked ferroelectrics. [ABSTRACT FROM AUTHOR]

For microscale gaps, DC breakdown voltage is described theoretically and through simulation by accounting for field emission generated electrons and the subsequent ionization of neutral gas and ion-induced secondary electron emission. Here, we extend DC microscale breakdown theory to AC. Particle-in-cell (PIC) simulations show that breakdown voltage V varies linearly with gap distance d independent of frequency and the ion-induced secondary electron coefficient γ S E for d ≲ 4 μ m , where field emission dominates breakdown over ionization and avalanche. For d ≳ 4 μ m and γ S E = 0 , DC breakdown voltage increases linearly with d; for γ S E = 0.05 , DC breakdown voltage decreases to a minimum before beginning to increase at larger gap distances. For AC fields with γ S E = 0.05 , V behaves similarly to the DC case with the decrease corresponding to secondary emission occurring at higher voltages and larger gap distances with increasing frequency. At 10 GHz and γ S E = 0.05 , V resembles that of the DC case with γ S E = 0 up to ∼8 μm, suggesting that increasing the frequency effectively changes the number of ions striking the electrodes and the resulting electrons released. Phase space plots showing electron and ion velocities as a function of position across the gap show that electrons and ions are increasingly trapped within the gap with increasing frequency, reducing the number of ions that can strike the cathode and the subsequent secondary emission. Incorporating the resulting effective secondary emission coefficient for AC microscale gaps yields a simple phenomenologically based modification of the DC microscale gas breakdown equation. [ABSTRACT FROM AUTHOR]

In recent years, interest in synthetic C4F7N as a gas insulator has been growing due to its unique insulation properties and low global warming potential. In spite of this, very few studies are devoted to the analysis of the electric breakdown of C4F7N and its mixtures with other dilutants such as CO2 and N2. In the present paper, we use a two-dimensional fluid model to analyze the electrical breakdown of the atmospheric pressure C4F7N/N2 mixture. We establish the influence of the C4F7N fraction in the mixture and the cathode voltage rise rate on the breakdown voltage. We find that the ratio between the electron attachment frequency and the voltage rise rate defines the streamer parameters. Namely, if the time scale of electron attachment to C4F7N is much faster than the voltage rise rate, the plasma electronegativity of the streamer body and of its head is extremely high, and it is difficult to define exactly the streamer head location. In the opposite case of the fast rise rates, the conventional streamers with sharp heads were obtained. [ABSTRACT FROM AUTHOR]

The conventional electrostatic solutions for two-dimensional (2D) electrodes possess edge singularities for the surface charge density σ and the normal component of the electric field E n. These singularities are generally non-physical because they admit infinite gradients of the concentration of free charge carriers. In particular, they are unacceptable in the studies of the local field sensitive effects, such as the electric breakdown and the ferroelectric domain reversal. We claim that account for diffusion of free charge carriers leads to the disappearance of the edge singularities. This generalization occurs consistently within the same basic concept of conduction. Specifically, we consider the case of U -biased circular disc electrode of radius a. Account for diffusion leads here to a strongly nonlinear integral 2D equation for the electrostatic potential φ (r). Numerical solution of this equation shows that the law σ (a) ∝ U 2 / a takes place. Outside a close vicinity of the disc edge, we stay close to the conventional electrostatic solution for φ and σ. [ABSTRACT FROM AUTHOR]

The reactivity of heterogeneous energetic materials (HEMs) intimately depends on the underlying microstructural effects. For reactive materials, key factors include the microstructure distribution, morphology, size scale of heterogeneities, reactant mixing, and chemical kinetics of the reactants. We report the development of a mesoscale model for simulating the evolutions of the hotspot field and associated reaction processes when such materials are exposed to external excitations. The model explicitly accounts for microstructure, interdiffusion between the reactant species, advection of the species mixture, and chemical kinetics of the reaction. An Arrhenius relation is used to capture the rate of reactive heat release. The particular material analyzed is a composite of poly(vinylidene fluoride-co-trifluoroethylene) and nanoaluminum [or P(VDF-TrFE)/nAl]. The excitation leading to the initial microstructural temperature increase that kicks off the exothermic reactive processes is the dissipative heating arising from dielectric breakdown under the electric field developed through piezoelectricity and flexoelectricity of P(VDF-TrFE). As such, the model resolves both the breakdown process and the diffusion, advection, and exothermic reaction processes. The evolutions of the temperature and species distribution fields under the combined effects of breakdown and chemistry are used to predict the effects of microstructure, diffusion, and kinetics on several key metrics characterizing the reactive responses of the material. This mesoscale framework admits the quantification of uncertainties in these predicted macroscopic behavior measures due to microstructure heterogeneity fluctuations through the use of multiple, random but statistically equivalent microstructure instantiations. Although the particular hotspot inducing mechanism considered is dielectric breakdown here, the framework can be adapted to analyze reaction initiation and propagation and establish microstructure–reaction behavior relations under other types of hotspot inducing mechanisms, such as thermomechanical inelastic dissipation, frictional heating, and laser or microwave excitation. [ABSTRACT FROM AUTHOR]

β-Ga2O3 is of great interest for power electronic devices with efficiency beyond current generation Si, 4H-SiC, and GaN devices due to its large breakdown electric field of ∼8 MV/cm. However, taking advantage of this large field strength in power diodes requires device engineering to reduce leakage current that arises at high electric fields. In this work, we elucidate the current transport mechanisms of metal/TiO2/β-Ga2O3 diodes, showing that thermionic emission is an excellent descriptor of current in forward and reverse bias. It is shown that tunneling current is greatly suppressed, and consequently, that the diodes with the TiO2 interlayer can block orders of magnitude more current than Schottky barrier diodes with the same barrier heights. Finally, a 1200 V diode structure is designed based on the derived transport models, and calculated on- and off-state current characteristics closely align with those of state-of-the-art 4H-SiC commercial devices, indicating that this diode structure is ready to enable the realization of β-Ga2O3 power diodes. [ABSTRACT FROM AUTHOR]

Energy-storage dielectrics are key enabling materials for high-density power converters, among which lead-free relaxor ferroelectric ceramics have received particular attention. Ba 0.82 Bi 0.12 TiO 3 in a simple chemical form demonstrates high energy density and efficiency at normal electric field. However, its low temperature stability at application-oriented DC-biased electric field is among the major obstacles hindering their progress. In this work, Ba 0.82 Bi 0.12 TiO 3 was modified with Sr substituting Ba via a superparaelectric engineering strategy, which is characterized by the enlarged zone between the dielectric peak and the Burns that moves towards lower temperatures. Ba 0.82 Bi 0.12 TiO 3 suffers from dielectric breakdown at DC-biased electric field of 200 kV/cm DC superimposed with 50 kV/cm AC and 25 °C, despite its good temperature stability at normal electric field. In contrast, the superparaelectric engineered (Ba 0.8 Sr 0.2) 0.82 Bi 0.12 TiO 3 maintains excellent temperature stability at the same DC-biased electric field in the fact that the energy density changes by less than 5 % and the efficiency remains above 90 % within the temperature range of 25 °C–125 °C. The superparaelectric strategy should be generally applicable to enhance temperature stability at DC-biased electric field in other relaxor ferroelectrics towards application in high-density power converters. [ABSTRACT FROM AUTHOR]

Replacing thermoset insulation by healable and recyclable covalent adaptable networks is a promising approach to the sustainable development of electrical and electronic devices. However, the repair performance gifted by dynamic covalent bonds always conflicts with the excellent mechanical properties gifted by stiff cross‐linked networks. In this paper, by introducing dynamic thiocarbamate bonds, polythiourethane (PTU) with excellent mechanical properties and electrical insulation comparable to commercial epoxy resins are successfully developed, which exhibit superior healability and recyclability properties. Sub‐centimeter scale electrical breakdown failures of the PTU samples could be efficiently self‐healed with a healing efficiency up to 90%, while the storage modulus and volume resistivity exceeded 2 GPa and 1016 Ω cm, respectively. Even though the electrical breakdown strength inevitably declined after multiple repair processes, PTU samples could restore their initial excellent insulation performance by simply reprocessing with the efficiency above 95%. Moreover, the efficient healability performance of large‐sized electrical breakdown failures remained after the reprocessing. These outstanding characteristics underscore the tremendous potential of PTU materials as a new generation of sustainable high voltage insulation. [ABSTRACT FROM AUTHOR]

The incorporation of rare-earth elements into BaTiO 3 -based multilayer ceramic capacitors (MLCCs) plays a pivotal role in enhancing the dielectric constant and reliability. In this study, The BaTiO 3 -based ceramics doped with La and Dy were prepared separately and their dielectric properties and reliability were thoroughly compared. The La-doped sample exhibited a significantly enhanced dielectric constant, which can be attributed to the short-range migration of liberated oxygen vacancies (V O • • ) facilitated by the incorporation of defects [ L a B a • ‐ M g T i ″ - L a B a • ]. However, the presence of free V O • • in the La-doped sample led to a significant reduction in insulation resistivity during the initial application of the electric field. Microstructural analysis of the failure points resulted in the proposal of an electrical breakdown model, which elucidates the superior breakdown strength observed in the La-doped sample. This study provides novel insights for the development of MLCCs with high dielectric constants and high reliability. [ABSTRACT FROM AUTHOR]

Al0.6Ga0.4N deep‐UV p–i–n avalanche photodiodes (APDs) are demonstrated grown by metalorganic chemical vapor deposition (MOCVD) on a (0001) c‐plane aluminum nitride (AlN) bulk substrate and fabricated both with and without an ion implantation process for mesa‐edge electric‐field termination. Three design considerations are taken into account: the optical absorption of the AlN bulk substrate, the photosensitivity of the APD, and the breakdown electric field. The MOCVD growth conditions of the AlGaN APD layers are optimized. Then, a detailed description of the seven device fabrication steps of the APDs is provided, which includes nitrogen ion implantation. The APDs fabricated by the ion implant process exhibit a dark‐current density under low reverse bias ≈1 × 10−9 A cm−2. This is one order of magnitude lower than the APD fabricated without ion implantation from the same wafer. The breakdown voltage of the APD is ≈−140 V. The calculated optical gain of the ion‐implanted APD beyond avalanche breakdown is ≈5.2 × 105 (current limited) and the device has an average zero‐bias photoresponse of ≈68 mA W−1 at a wavelength of 250 nm. [ABSTRACT FROM AUTHOR]

Herein, A high‐performance GaN vertical trench‐gate metal‐oxide‐semiconductor field‐effect transistor (MOSFET (UMOSFET)) with polyimide (PI) as the thick‐bottom dielectric (TBD) is numerically studied and experimentally demonstrated. It is demonstrated that the inclusion of TBD can effectively suppress the peak electric field at the bottom corner of the gate trench and prevent premature breakdown of the devices. According to the technology computer‐aided design simulation results, the UMOSFETs with larger TBD thickness (tTBD) exhibit enhanced breakdown voltage (VBR) with minor expense of specific on‐resistance (Ron,sp) and a significantly improved Baliga's figure of merit. Compared with the conventional GaN UMOSFETs without TBD, the fabricated GaN UMOSFETs with 500 nm‐thick PI as TBD feature a remarkable 1.5 times enhancement in breakdown voltage VBR to 407 V, highlighting the feasibility and potential of the PI‐TBD to propel the further development of GaN vertical devices toward the inherent material and device ultimate. [ABSTRACT FROM AUTHOR]

Large polarization and high breakdown strength are the key to achieving an idea energy storage density in dielectric capacitors, but unfortunately the trade-off problem between them is difficult to evade, particularly for those dielectrics with different crystalline degrees. Herein, we propose an appropriate polarization-breakdown synergistic strategy of dielectric multilayer films through temperature gradient annealing. The dielectric properties of a serials of (Pb, La)(Zr, Ti)O 3 /SrTiO 3 /(Pb, La)(Zr, Ti)O 3 (PLZT/STO/PLZT) structures with different annealing temperature for each layer are compared. The optimum recoverable energy density of 57.9 J/cm3 is achieved at a high breakdown electric field of 5.78 MV/cm and a moderate maximum polarization of 22.5 μC/cm2. In addition to the role of suppressing the carriers transport of interlayer STO, the balance between polarization and breakdown strength in bottom and top PLZT layers with individual dielectric characteristics should be responsible for the enhanced energy storage performance (ESP). The results suggest that it is a feasible way to optimize the ESP of dielectric multilayer films through designing different stacking layer via temperature gradient annealing heat treatment. [ABSTRACT FROM AUTHOR]

Silicone rubber (SR) is an ideal dielectric elastomer substrate due to its excellent flexibility and fast response speed. However, the innate low dielectric permittivity (ε) of SR generally requires a rather high driving voltage that restricts its widespread application. Typical attempts to increase ε of SR usually deteriorate either its flexibility or electrical stability. Herein, conductive multi‐walled carbon nanotube (MWCNT) were first surface modified with polyphenols (PNs) (MWCNT@PNs), aiming to facilitate its well dispersion within SR matrix, which may maintain the softness and electrical stability of SR via suppressing concentrated physical crosslinking and local leakage current flow. Then, five‐layered MWCNT@PNs/SR composites were prepared with the outer two insulating layers of SR while middle three dielectric layers of MWCNT@PNs filled SR. The multilayered structure further hindered the formation of conductive pathways through the composites, promising a high breakdown strength of the composites. Therefore, the multilayered MWCNT@PNs/SR composites exhibited increased ε, maintained low Young's modulus and electrical breakdown strength compared with pure SR of the same five‐layered structure. Among them, the composite with uniformly distributed MWCNT@PNs (m‐1: 1: 1) showed a highest actuation strain of 11.9% (at 19.6 kV mm−1), which was 4.1 times higher than that of SR (2.9% at 19.1 kV mm−1). [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric film capacitors exhibit high power density with ultra-fast charge and discharge rates, making them highly advantageous for consumer electronics and advanced pulse power supplies. The Aurivillius-phase bismuth layered ferroelectric films can effectively achieve a high breakdown electric field due to their unique insulating layer ((Bi2O2)2+ layer)). However, designing and fabricating Aurivillius-phase bismuth layer relaxor ferroelectric films with optimal energy storage characteristics is challenging due to their inherently stable ferroelectric properties. In this work, lead-free CaBi4-xLaxTi4O15 films were synthesized using the sol–gel technique and a weakly coupled relaxor design. On one hand, the introduction of La3+ ions weaken the dipole–dipole interactions, thereby enhancing the relaxor behavior. Alternatively, the expansion of grain size is restricted to enhance the number of grain boundaries, which possess improved insulating properties. This leads to a higher breakdown electric field. The results indicate that CaBi4-xLaxTi4O15 (x = 1.0) films exhibit excellent recoverable energy storage density (70 J/cm3) and high energy efficiency (73%). Moreover, the film exhibited good temperature stability and frequency stability. This study not only identifies a promising material for dielectric film capacitors but also demonstrates that the energy storage capabilities of Aurivillius-phase bismuth layer ferroelectric films can be effectively modulated through a design incorporating weakly coupled relaxor characteristics. [ABSTRACT FROM AUTHOR]

Perovskite relaxor ferroelectrics have been widely developed for energy storage applications due to their exceptional dielectric properties. This work explores the energy storage performance, thermal stability, and structural evolution in (1- x)BiFeO 3 – x Ba(Ti 0.8 Zr 0.2)O 3 ceramics (x = 0.3, 0.4, 0.5, and 0.6) via modulating Ba(Ti 0.8 Zr 0.2)O 3 (BZT) concentration. An enhancement of breakdown electric field from 120 kV/cm at x = 0.3–220 kV/cm at x = 0.5 can be attributed to increased grain boundaries and nanodomains as electric barriers to inhibit charge mobility. A high recoverable energy density of 5.9 J/cm3 and a high energy efficiency of 86.2 % were achieved at x = 0.5 and 0.6, respectively. The structure shifts from ferroelectric rhombohedral R 3 c symmetry toward a coexistence of nonpolar symmetries (including tetragonal P 4/ mmm , cubic Pm -3 m , and orthorhombic Pbnm) with increasing BZT. The integration of BZT in BiFeO 3 demonstrates to break the long-range order and promote the formation of polar nanoregions and nanodomains, leading to a high-efficiency energy storage. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of lead-free dielectric capacitors with high recoverable energy storage density and high energy storage efficiency is important for improving the overall performance of electronic and power systems. BaTiO 3 (BTO) is one of the most common ferroelectric materials and has attracted much attention for energy storage applications in the past decades due to its excellent dielectric and ferroelectric properties. However, high remnant polarization and low electrical breakdown strength of BTO limit its development in energy storage applications. Many efforts (e.g., elements doping, interface/heterostructure, etc.) have been made to improve the energy storage density of BTO thin films. In this paper, Ba 1-x Ni x TiO 3 thin films (x = 0, 0.02, 0.04, 0.06, 0.08; abbreviated as BN x T) were synthesized via sol-gel and spin-coated method. The effect of Ni doping on the structural, dielectric, ferroelectric and energy storage properties of BTO thin films has been studied. The results confirmed that with the increase of Ni doping, a second phase arises and the dielectric constant decreases. While appropriate Ni doping led to the improvement of the breakdown strength, further increase of Ni deteriorated the energy storage because of the high oxygen vacancy. Finally, optimized energy storage performance was obtained for BN 0.04 T thin film: dielectric constant of 401, dielectric loss of 0.002, recoverable energy density of 20.2 J/cm3 and energy storage efficiency of 83.6% at 965 kV/cm. Meanwhile, the remnant and maximum polarization of the films were 0.06 μC/cm2 and 50 μC/cm2, respectively. BN 0.04 T thin film has an excellent application prospect and is expected to appear as a component in the future composite energy storage film system. [ABSTRACT FROM AUTHOR]

In this study BNBCTS ceramics were co-doped with Fe and Sb to form (Bi 0.5 Na 0.5) 0.93 (Ba 0.945 Ca 0.055) 0.07 (Ti (0.9946-x) Sn 0.0054)(Fe 0.5 Sb 0.5) x O 3 ceramics (denoted as BNBCTS-xFS) with various x content and were prepared via the solid-state combustion technique to enhance the electrical and energy storage performance. The effect of co-doping Fe and Sb on the phase formation, defect dipole, microstructure, electrical and energy storage properties of BNBCTS-xFS ceramics was studied. When x content increased from 0.0 to 0.030, the amount of the rhombohedral (R) phase decreased from 51 to 24 % while the tetragonal (T) phase increased from 49 to 76 %. The increased Fe and Sb content increased the defect dipole of singly/doubly charged oxygen-vacancies (V O ∙ / V O ∙ ∙ ) and caused more Ti4+ to transition to Ti3+, which caused the transition temperature of the ferroelectric phase to relaxor state (T F-R) in the ceramics to drop to below room temperature and it exhibited relaxor characteristics at room temperature. The ceramic with an x content of 0.010 had the largest grain size (3.06 μm), excellence ferroelectric properties (P r ∼31.04 μC/cm2, P m ∼38.98 μC/cm2 and E c ∼18.28 kV/cm), the largest electro strain (∼0.175 %) and a large d 33 * of 350 pm/V. Moreover, when x = 0.020, the ergodic relaxor ceramic showed the smallest grain size (1.03 μm), the lowest remanant polarization (P r) of 4.52 μC/cm2 and the lowest coercive field (E c) of 8.37 kV/cm, at an electric field of 60 kV/cm. More importantly, energy storage properties at the electric breakdown strength (E b = 120 kV/cm) of the ceramics with an x content of 0.020 exhibited a recoverable energy storage density (W rec) of 1.81 J/cm3, a total energy storage density (W total) of 2.95 J/cm3 and an efficiency (η) of 61.30%, with excellent thermal (∼25–150 °C) and frequency stability (∼1–100 Hz). This study provides new insights into the modulation of BNBCTS ceramics with Fe and Sb co-doping, which could effectively improve the electrical properties and energy storage properties of BNBCTS-xFS ceramics. [ABSTRACT FROM AUTHOR]

Insulating materials can be classified into solid, liquid, and gaseous forms. Solid insulation materials are divided into different types such as organic, inorganic, and polymer types. In electrical circuits, solid insulation materials are generally used as components that provide insulation and mechanical support. In recent years, as a result of developing technologies, the production of participation insulation materials with 3D printing technology has become widespread. Three-dimensional printing technology enables the rapid creation of objects by combining materials based on digital model data. It is important to evaluate the materials produced with 3D printing in terms of insulation coordination. Studies have shown that the electrical breakdown strength of solid dielectrics varies depending on factors such as sample type, thickness, the magnitude of applied voltage, and the temperature of the physical environment. According to IEC-60243 standards, there are various methods to measure the breakdown strength of solid insulators applied to different voltage types. In this study, the behavior of PLA, ABS, ASA, PETG, and PC/ABS materials produced with 3D printing and having the potential to be used as insulation materials when exposed to high voltage within the scope of insulation coordination was investigated. The breakdown strengths of solid insulation materials produced with 3D printing were measured in the high-voltage laboratory within the scope of IEC-60243. Breakdown strength was statistically evaluated with the Weibull distribution. Damage analysis of the breakdowns in the test specimens was examined in detail with ImageJ software. With the comparative analysis, the behaviors of PLA, ABS, ASA, PETG, and PC/ABS solid insulation materials were revealed and their superiority over each other was determined. [ABSTRACT FROM AUTHOR]

Ga2O3 based solar‐blind avalanche photodetectors (APDs) are promising for week photodetection in both civil and military applications due to low‐voltage operation, compact dimensions, and optical filter‐free. However, the performance is impeded by low surface‐to‐volume ratio, low barrier height, and elevated dark current. Herein, a 1D ZnO/HfO2/Ga2O3 core@dual‐shell radial heterostructure is designed for high‐performance solar‐blind APDs. A single‐crystal ZnO microwire with smooth surface serves as core framework for shell growth with small lattice mismatch. By incorporating an HfO2 barrier layer, the conduction band offset is further increased to 2.15 eV without introducing a valence band barrier that would impede hole transport, forming a unipolar barrier structure. This high unipolar barrier suppresses dark current effectively, increases the avalanche breakdown electric field, and enhances the avalanche gain. The optimized APD achieves a responsivity of 2.2 × 105 A W−1 and a detectivity of 3.1 × 1016 Jones, with an avalanche gain of 4.7 × 104, which is 16 times higher than the HfO2‐free barrier layer‐modified device. Additionally, it exhibits long‐time stability with a response time of 6.4 ms and a solar‐blind/UVA rejection ratio of 6.25, ensuring immunity to solar interference. This work offers greater design flexibility to develop high‐performance Ga2O3‐based APDs and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

Stretching fields give rise to the formation of reinforcing crystals in biaxially oriented polypropylene capacitor films, endowing them with excellent electrical properties. In this paper, the correlation between stretching temperature, ratio, and annealing temperature and film structure as well as electric breakdown strength (Eb) during biaxial stretching is investigated. Synchronous biaxial stretching ensures that the orientation of the prepared films is isotropic. However, the changes caused by the stretching field occur in the lamellae structure, with a gradation of thick and thin lamellae. First, an increasing stretching ratio leads to the homogenization of the crystal toward thick lamellae, increasing Eb. Second, the onset melting temperature (Tonset) is the key to the gradation of thick and thin lamellae. Stretching near or above Tonset results in a reduced order of the recrystallization precursors and forms thin lamellae, degrading Eb. Additionally, annealing below the melting point promotes chain migration, which facilitates the homogenization to thick lamellae and improves Eb. In conclusion, the improvement of Eb is related to the homogenization of lamellae thickness. These results provide new insights for optimizing film processing and crystal structure to enhance electrical insulation. [ABSTRACT FROM AUTHOR]

2D) Van der Waals ferroelectrics offer the opportunity for developing novel nanoelectronics devices. For device applications, it is necessary to generate controllable ferroelectric polarization domains and achieve non‐destructive polarization switching. However, it is very challenging to use the electric field to manipulate the domain state of ultra‐thin ferroelectric film due to the large leakage current and even electric breakdown. Here, the flexoelectric effect on the manipulation of polarization states at bending α‐In2Se3 flakes is explored via piezoresponse force microscopy (PFM). By introducing patterned Si trench substrates, the stripe micron‐scale ferroelectric domains with alternating arrangements of the out of‐plane polarization in the curved α‐In2Se3 are observed. It is found that the polarization at the bending region of α‐In2Se3 can be directly reversed by the large flexoelectric field. The controllable mechanical modulation of α‐In2Se3 ferroelectric domains opens up potential applications of ferroelectrics in strain engineering functional devices. [ABSTRACT FROM AUTHOR]

Biotite, an iron-rich mineral belonging to the trioctahedral mica group, is a naturally abundant layered material (LM) exhibiting attractive electronic properties for application in nanodevices. Biotite stands out as a non-degradable LM under ambient conditions, featuring high-quality basal cleavage—a significant advantage for van der Waals heterostructure (vdWH) applications. In this work, we present the micro-mechanical exfoliation of biotite down to monolayers (1Ls), yielding ultrathin flakes with large areas and atomically flat surfaces. To identify and characterize the mineral, we conducted a multi-elemental analysis of biotite using energy-dispersive spectroscopy mapping. Additionally, synchrotron x-ray fluorescence and infrared nano-spectroscopy were employed to probe its iron content and vibrational signature in few-layer form, respectively, with sensitivity to the layer number. We have also observed good morphological and structural stability in time (up to 12 months) and no important changes in their physical properties after thermal annealing processes in ultrathin biotite flakes. Conductive atomic force microscopy evaluated its electrical capacity, revealing an electrical breakdown strength of approximately 1 V nm−1. Finally, we explore the use of biotite as a substrate and encapsulating LM in vdWH applications. We have performed optical and magneto-optical measurements at low temperatures. We find that ultrathin biotite flakes work as a good substrate for 1L-MoSe2, comparable to hexagonal boron nitride flakes, but it induces a small change of the 1L-MoSe2 g -factor values, most likely due to natural impurities on its crystal structure. Furthermore, our results show that biotite flakes are useful systems to protect sensitive LMs such as black phosphorus from degradation for up to 60 days in ambient air. Our study introduces biotite as a promising, cost-effective LM for the advancement of future ultrathin nanotechnologies. [ABSTRACT FROM AUTHOR]

Plasma discharges under atmospheric pressure can be used to modify the electrical properties of metallic and dielectric surfaces. The aim of such a modification is to achieve an improvement in the characteristic parameters of the surface, for example in the area of the electrical strength of the surface, in order to achieve a higher ultimate level of electrical breakdown Eb when tested with pulsed or alternating electrical voltages. So far, research has focused on a set of functional experiments carried out using plasma on samples of two types of dielectric materials (thermoset, thermoplastic) with an impact on the final effect of the level of electrical breakdown voltage, electrical intensity and Eb. surface conductivity. The treatment technology requires repeatability and consideration of the industrial deployment conditions of plasma technology. The surface structure was modified in a defined and repeatable way by plasma discharge under atmospheric pressure without the presence of precursors. Methods to evaluate these modifications assessed the change in parameters related to sample type, repeatability and prediction of treatment stability. Subsequently, the surface strength of both the modified samples and the samples not affected by the plasma discharge was measured. [ABSTRACT FROM AUTHOR]

Herein, we report electronic transport properties of transparent thin film transistors (TFTs) prepared using Sn: ZnO/ZrO2 thin films grown by dc magnetron sputtering. The fabricated devices potentially operate in low voltage mode with a high breakdown electric field. The effect of active channel length on the TFT characteristics is discussed. The high-k ZrO2 thin films were deposited at room temperature and their physical properties and their electrical characteristics such as leakage current and impedance characteristics were investigated prior to TFT fabrication. The fabricated TFTs have exhibited a current on/off ratio 105, a maximum field effect mobility of 18.30 cm2(V.s)−1 and a sub-threshold swing slope of 223 mV/dec. The average optical transmittance of the bilayers was ~ 85% in the visible region. The present results show that the chosen materials are promising for the fabrication of transparent TFTs. [ABSTRACT FROM AUTHOR]

This study explores the impact of adding conventional mineral oil (10%, 30%, and 50%) to new natural esters (Jatropha-based methyl ester and refined coconut oil). Examining dielectric, fire properties, and gassing tendencies, samples undergo accelerated aging at 130 °C with metallic substances. Results reveal that up to 30% mineral oil enhances or maintains the electrical and physical properties of natural esters, with dissipation factor reduction and viscosity improvement (by a factor of 2 at 50% mineral oil). Overall, mineral oil positively influences the insulating properties of natural esters under the described test conditions, suggesting potential applications in electrical systems. [ABSTRACT FROM AUTHOR]

• Less frequent observations of sprites over winter storms are consistent with theory. • Due to lower charge centers sprite inception in winter is limited. • Wind shear causes an observable horizontal shift in sprite inception. Transient luminous events (TLEs) is the collective name given to mesospheric electrical breakdown phenomena occurring in conjunction with strong lightning discharges in tropospheric thunderstorms. They include elves, sprites, halos, and jets, and are characterized by short lived optical emissions, mostly of red (665 nm) and blue (337 nm) wavelengths. Sprites are caused by the brief quasi-electrostatic field induced in the mesosphere, mostly after the removal of the upper positive charge of the thundercloud by a +CG, and they have been recorded above most of the lightning activity centers on Earth. In wintertime, there are just a few areas where lightning occurs, and of those, sprites have been observed over the Sea of Japan, the British Channel, and the Mediterranean Sea. Unlike their summer counterparts, winter thunderstorms tend to have weaker updrafts and as a result, reduced vertical dimensions and compact charge structures, whose positive and negative centers are located at lower altitudes. These storms are often susceptible to significant wind shear and as a result may exhibit a tilted dipole charge structure and a lateral offset of the upper positive charge relative to the main negative charge. We present results of numerical simulations using a three-dimensional explicit formulation of the mesospheric quasi-electrostatic electrical field following a lightning discharge from a typical mid-latitude winter thunderstorm exhibiting tilt due to wind shear and evaluate the regions of possible sprite inception. Our results show, as numerous observations suggest, that sprites can be shifted a large distance from the location of the parent +CG in the direction of the shear and will occur over a larger region compared with non-sheared storms. [ABSTRACT FROM AUTHOR]

To evaluate the deterioration degree of insulation material by monitoring partial discharges (PDs), it is necessary to fully understand the PD behavior prior to breakdown. We performed measurements of temporal variations in the number and magnitude of PDs in a void of epoxy resin. It was found that the number of PDs with larger magnitude is less before breakdown and that there is a decreased tendency of the number and magnitude of PDs with the elapsed time. The tendency is remarkable as the applied electric field is small. Additionally, the time to breakdown becomes short when the scattering of the number of PDs per unit time decreases. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This study focuses on the performance evaluation of the structural and electrical characterization with various gas concentrations of bilayer oxide gate dielectric ZrO2 and Ho2O3 thin films on a 4H–SiC substrate. The structural characterization of XRD, FTIR, and XPS indicated the formation of Zr–O, Ho–O, Zr–O–Si, and Ho–O–Si bonds. The cross sections of oxide layers were examined through a high-resolution transmission electron microscope with a physical thickness of 4.77 to 5.53 nm. The absence of interfacial layers has been reasoned due to nitrogen atoms affect causing blockage of charge movement and oxygen diffusion between oxide layers and 4H–SiC substrate. It was observed that the ZrO2/Ho2O3/SiC sample underwent oxidation with a gas concentration ratio of 90% O2:10% N2 has the highest energy band alignment of conduction band offset Δ E v ~ 3.18 eV and valence band offset Δ E c ~ 5.38 eV with highest electrical hard breakdown field of 9.7 MVcm−1. The effective dielectric constant ( k eff ) ~ 33.54, effective oxide charge ( Q eff ), average interface trap density ( D it ), and slow-trap density have been obtained from the derivation of capacitance–voltage plot. The analysis supports the conclusion that the bilayer thin film oxidized with a gas concentration ratio of 90% O2:10% N2 produced the optimal electrical performance. This may serve as a high-k gate dielectric application in metal–oxide–semiconductor-based devices. [ABSTRACT FROM AUTHOR]

Silicone gel, used in the packaging of high-voltage, high-power semiconductor devices, generates bubbles during the packaging process, which accelerates the degradation of its insulation properties. This paper establishes a testing platform for electrical treeing in silicone gel under pulsed electric fields, investigating the effect of pulse voltage amplitude on bubble development and studying the initiation and growth of electrical treeing in a silicone gel with different pulse edge times. The relationship between bubbles and electrical treeing in silicone gel materials is discussed. A two-dimensional plasma simulation model for bubble discharge in silicone gel under pulsed electric fields is developed, analyzing the internal electric field distortion caused by the response times of different ions and electrons. Additionally, the discharge current and its effects on silicone gel under pulsed electric fields are examined. By studying the influence of different pulse edge times, repetition frequencies, and temperatures on discharge current magnitude and ozone generation rates, the impact of electrical breakdown and chemical corrosion on the degradation of organic silicone gel under various operating conditions is analyzed. This study explores the macroscopic and microscopic mechanisms of dielectric performance degradation in organic silicone gel under pulsed electric fields, providing a basis for research on high-performance packaging materials and the development of high-voltage, high-power semiconductor devices. [ABSTRACT FROM AUTHOR]

Featured Application: This work measures the nanosecond pulsed breakdown performance of C 4 F 7 N and compares it to that of SF 6 . The results indicate that C 4 F 7 N and its various mixtures exhibit certain advantages in breakdown behavior over simply pure SF 6 in pulsed spark gaps. This report evaluates the pulsed breakdown performance of C 4 F 7 N under a 6.8 kV/ns voltage excitation. The pulsed dielectric strength of C 4 F 7 N is compared to S F 6 in the same experimental setup, and it is found that C 4 F 7 N concentrations of 50% or greater are required to achieve a dielectric strength greater than or equal to S F 6 . Pure C 4 F 7 N demonstrated higher electric field hold-off for longer time periods and less statistical variance under pulsed conditions when compared to S F 6 . Mixtures of 50% C 4 F 7 N with N 2 or C O 2 as buffer gases showed no appreciable difference in pulsed dielectric strength. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) harvesting ocean wave energy is an effective method to alleviate the energy crisis. However, the breakdown phenomenon is ubiquitous for the TENG with a large area of dielectric layer, which not only limits the output and reliability but also highly risks the device failure. Here, a self‐recovery TENG (SR‐TENG) featuring high breakdown resistance is designed, which achieves a high output charge density of 4.24 mC m−2 with the assistance of the charge excitation technique, as well as maintains 87% of the initial output even after six times fierce electric breakdown, minimizing the negative impacts of the breakdown phenomenon. Besides, based on the SR‐TENG, a symmetric anaconda‐shaped self‐charge excited TENG is designed for effective water wave energy harvesting. This work not only sheds light on the self‐recovery phenomenon in TENGs, but also represents a significant step toward the high performance TENG featuring high breakdown resistance and ultimate stability, accelerating the practical applications of TENG for blue energy harvesting. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) is believed to be a rather promising cable insulating material for high‐capacity electric power system with low carbon emission due to its decent thermo‐resistance and recyclable nature. In this paper, a new dually chemical grafting modification strategy by methyl acrylate (MA) and acrylic acid (AA) is put forward to tailor the charge transportation behavior in PP, thus further enhancing the electrical properties. Experimental results indicate that the dually grafted PP with 2.3 weight percent (wt%) MA and 1.9 wt% AA shows enhanced volume resistivity and electrical breakdown strength than pure PP, and the space charge injection is significantly suppressed. This work further adopts thermally stimulated depolarization current (TSDC) test and computational analysis based on density functional theory (DFT) to reveal the mechanism of enhancement. The analysis shows that grafted chemical groups can introduce quantities of deep traps and electrostatic potential wells which are strongly correlated with the carbonyl group and would hinder the charge transportation thus improving the electrical insulating performances of PP. This work would provide a new route of PP‐based dually grafting modification for the development of high‐voltage cable insulation. [ABSTRACT FROM AUTHOR]

Dielectric capacitors are commonly used in electronic and electric power systems due to their excellent charging and discharging rates and ultra-high power densities. Especially, with the rapid development of new energy vehicles industry, high-temperature films capacitors are urgently needed, while the conductivity loss of polymer capacitive films at high temperatures sharply increases, which should be significantly suppressed for achieving excellent energy storage performance. This paper presents a composite film with polyetherimide (PEI) as the matrix, and core-shell structured particle ceramic as fillers where high polarization of barium strontium titanate (BaSrTiO 3) as the core and excellent insulation strength of alumina (Al 2 O 3) as the shell, respectively, achieving a synergistic enhancement of breakdown strength and dielectric constant of Al 2 O 3 @BaSrTiO 3 /PEI composite film. More importantly, the Al 2 O 3 layer with moderate dielectric constant can effectively relieves the electric field distortion at the interfacial regions due to the large difference between BaSrTiO 3 fillers and PEI matrix. The composite film demonstrates exceptional thermal and cycling stability, as well as energy storage properties within the studied temperature range, a discharge energy density of 4.67 J/cm3 at 150 °C. The enhanced mechanism of energy storage performance is revealed bycomparatively analyzing of the microstructure and dielectric properties of BaSrTiO 3 /PEI, Al 2 O 3 /PEI, and Al 2 O 3 @BaSrTiO 3 /PEI composite films. This paper presents a modification strategy of inorganic/organic composite films by increasing both of dielectric constant and electric breakdown strength at elevated temperature. [ABSTRACT FROM AUTHOR]

Lead-free dielectric capacitors have become a topic of great interest in response to the ever-increasing demand for high-performance and environmentally friend energy devices. As SrTiO 3 (STO) is paraelectrics, the extremely low spontaneous polarization limits the development of its energy storage applications. In this paper, the microstructure and ferroelectric properties of STO are adjusted by grain engineering to expand its application in energy storage. STO, SrTi 1-x Mn x O 3 (STM x , x = 0.01 and 0.04) and Sr 1-y La y TiMn 0.01 O 3 (SL y TM 0.01 , y = 0.01, 0.02, 0.03 and 0.04) thin films are synthesized by the sol-gel method and thoroughly investigated on the effects of A-site (La) and B-site (Mn) co-doping effects on the crystalline phase, morphology, dielectric, ferroelectric and energy storage characteristics of STO thin film. The results indicate that the SL 0.01 TM 0.01 thin film exhibits a breakdown electric field of 3666.2 kV/cm. The SL 0.02 M 0.01 thin film exhibits excellent frequency stability and low dielectric loss (<0.01) with an energy storage density of 29.5 J/cm3 and an efficiency of 83.7 % at 2600 kV/cm. Moreover, the sample shows good frequency stability (400–2800 Hz) and thermal stability (20−140 °C). These findings indicate the potential of (Mn, La) co-doped SrTiO 3 thin film for dielectric capacitor energy storage field applications. [ABSTRACT FROM AUTHOR]

Beta-phase gallium oxide, β-Ga2O3, in transistors and diodes has been reported due to its distinctive electrical characteristics, such as wide bandgap, low leakage current, and high breakdown electric field. However, besides such conventional basic devices, more advanced device applications using β-Ga2O3 are always necessary. Here, we report on the dynamic behavior of Pt/β-Ga2O3-based Schottky diode for power-efficient organic light emitting display (OLED). Two Schottky diodes are back-to-back connected in series to form a half-wave rectifier circuit and finally integrated with an OLED diode pixel. When AC voltage is applied to the circuit at a frequency greater than 60 Hz, blinking of the OLED light is indistinguishable to human eyes. By way of the rectifier circuit, the OLED pixel efficiently saves more than 35% of the power that should be consumed by applying DC voltage. [ABSTRACT FROM AUTHOR]

Dielectric capacitors are widely used in aerospace, power systems, and other fields. Working environments with ever‐increasing temperatures pose a new challenge to energy storage performance. Polyetherimide (PEI) has gained extensive research for its good high‐temperature properties. In order to further improve its energy storage performance at high temperatures, many researchers have worked on PEI all‐organic composites doping with molecular semiconductors. Previous studies generally only considered the effect of introduced deep traps on macroscopic properties such as electrical conductivity, electrical breakdown, and energy storage performance. It has been shown that only qualitative analyses can be performed from the perspective of charge trapping, and it is difficult to obtain quantitative results. Therefore, this work proposes to study the macroscopic properties of polymer dielectrics by combining charge trapping with molecular displacement. A comprehensive conduction‐breakdown‐energy storage model was established to explain the influence mechanism of molecular semiconductors on the improved energy storage performance of PEI composites at high temperatures. The molecular semiconductor fillers increase the coefficient of friction between molecular chains, which restricts the movement of molecular chains and also limits charge hopping. Therefore, the dielectrics have higher breakdown strengths and smaller conduction losses, which synergistically enhance the energy storage performance. [ABSTRACT FROM AUTHOR]

Nowadays, the third-generation semiconductor led by GaN has brought great changes to the semiconductor industry. Utilizing its characteristics of a wide bandgap, high breakdown Electric field, and high electron mobility, GaN material is widely applied in areas such as 5G communication and electric vehicles to improve energy conservation and reduce emissions. However, with the progress in the development of GaN electronics, surface and interface defects have become a main problem that limits the further promotion of their performance and stability, increasing leakage current and causing degradation in breakdown voltage. Thus, to reduce the damage, Plasma treatment technologies are introduced in the fabrication process of GaN electronics. Up to now, designs like the high-resistivity p-GaN cap Layer, passivating termination, and surface recovery process have been established via Plasma treatment, reaching the goals of normally-off transistors, diodes with high breakdown voltage and high-reliability GaN electronics, etc. In this article, hydrogen, fluorine, oxygen, and nitrogen Plasma treatment technologies will be discussed, and their application in GaN electronics will be reviewed and compared. [ABSTRACT FROM AUTHOR]

The ZrO2–HfO2 oxide films are prepared by pulsed chemical vapor deposition using volatile organometallic precursors. It is shown that the morphology, thickness, and uniformity of the resulting coatings are affected by the mode of reaction space organization. A 360 nm thick oxide coating is obtained by introducing the precursor vapor and the reactant gas into the reactor through an earlier elaborated system of separate reaction components supply. The atomic force microscopy data show that the resulting surface is almost smooth and has an arithmetic average roughness of a few nanometers. Current-voltage and capacitance-voltage characteristics of the obtained ZrO2–HfO2 oxide coatings are studied. It is noted that the breakdown electric field is almost independent of the oxide coating thickness (0.1-0.48 MV/cm) in the interval of 225-325 nm. The breakdown electric field increases as the oxide film thickness increases from 325 nm to 360 nm. The dependence of the dielectric constant on the oxide film thickness is determined from the measured capacitance-voltage characteristics of the obtained ZrO2–HfO2 films. It is shown that this dependence depends linearly on the film thickness. [ABSTRACT FROM AUTHOR]

Dampness in the joint is a common defect of power cables, and the influence of moisture on the performance of the intermediate joint is very important. The electric field distribution of the joint is analyzed by simulation, and the XLPE sample is used as an experimental object to test the breakdown voltage under different damp levels. Simulation results show that in the composite interface outside the main insulation, the electric field at the water film is only 20%–60% of normal. However, the electric field around the water film generally increases, and as the degree of moisture increases, the electric field distortion becomes more serious, which is prone to inducing breakdown accidents. The electric field around the water film outside the conductor has no obvious distortion and will not directly induce accidents. Through the breakdown voltage experiment of the damp XLPE sample, it is found that the average breakdown voltage is 85%–94% of normal, and it decreases with the increase of moisture. The experimental results are consistent with the simulation results. The results can be used to guide the cause analysis of cable intermediate joint accidents. [ABSTRACT FROM AUTHOR]

V‐shaped composite insulator strings exhibit excellent resistance to pollution and wind deviation, resulting in their widespread use in transmission lines. The correlation between inclination angle of the shed surface and pollution flashover voltage can reflect the pollution flashover characteristics of V‐shaped composite insulator strings. Therefore, the relationship between inclination angle and pollution flashover voltage was studied through artificial pollution testing methods, and the relationship between inclination angle and degree of wetting was studied using the method of adding water to increase weight. The results of this study indicated that as the inclination angle increased within the range of 0°–180°, the degree of wetting on the surface of contaminated silicone rubber gradually decreased, whereas the pollution flashover voltage continuously increased. A model of water droplet collision and wetting on the surface of contaminated silicone rubber at different inclination angles was established. This model revealed that the gravity‐induced difference in the wetting states of the surface of contaminated silicone rubber under different inclination angles was responsible for the variation in pollution flashover voltages, with the maximum variation being 116.52%. The results of this study can inform the design and operation of V‐shaped composite insulators. [ABSTRACT FROM AUTHOR]

High‐voltage electric pulse rock breaking has excellent potential for exploiting deep geothermal resources. Numerous researchers have conducted experimental studies on this topic, particularly in rock mechanics, where the breakdown occurs. However, there has been limited scholarly research on drilling fluid. Therefore, the study focuses on the drilling fluid suitable for electric pulse drilling, considering the characteristics of electric pulse rock breaking, which differ from traditional rock breaking. The study focused on the impact of various drilling fluid parameters on the effectiveness of electric impulse rock breaking using red sandstone as the experimental material. This was investigated using the finite element method, and indoor electric rock‐breaking tests were conducted in a drilling fluid environment. The results indicate that the plasma channel mainly grows in the permeable layer of the drilling fluid, resulting in shallow rock breaking depth in the drilling fluid environment. The pore permeated by drilling fluid guides the growth of the plasma channel. The higher the conductivity of the drilling fluid, the closer the ion channel of rock breaking by electric pulse is to the rock surface. This results in a smaller crushing volume and shallower damage depth, which is more detrimental to rock breaking by an electric pulse. The viscosity of drilling fluid can impede the breakdown to some extent. In this paper, the influence of drilling fluid parameters on electro‐pulse rock‐breaking technology is preliminarily studied, which has significant reference value for the selection of actual drilling fluid. [ABSTRACT FROM AUTHOR]

High-voltage electric pulse rock-breaking technology has the potential to improve drilling speed significantly. Numerous mechanism studies and laboratory experiments have laid the foundation for developing high-voltage electric pulse rock-breaking technology. However, the mechanism of medium ion channels growing in three dimensions has yet to be fully understood. Based on this, the paper constructs a prediction model of the electrical breakdown trajectory in three dimensions using the finite difference method. The model considers the dielectric properties of the mineral particles inside the rock. The paper then simulates and analyzes the generation of plasma channels caused by the electrical breakdown of rock in space. This is done using the MATLAB numerical simulation software, in combination with the analysis of the electric rock-breaking circuits and the Probabilistic Development Model (PDM). The laboratory experiment on electric rock breaking verifies the prediction model for the trajectory of electrical breakdown. The research results show that the plasma channel generated by electric breakdown in rocks is a spatial curve that expands between the high-voltage electrode and the ground electrode. The breakdown points generated near the high-voltage electrode are more concentrated than those near the ground electrode, forming the primary fragmentation zone. The area near the ground electrode is the secondary fragmentation zone. The voltage difference between the high-voltage level and the grounding electrode significantly influences the crushing effect. A higher voltage leads to a more pronounced crushing effect at the high-voltage electrode. The research results have definite guiding significance for the engineering application of high-voltage pulse rock-breaking technology and the design of downhole drilling tools. Highlights: In this paper, a three-dimensional trajectory prediction model of electrical breakdown is established to study the electrical breakage of rock. The electric breakdown three-dimensional trajectory prediction model is utilized to simulate electrical breakdown in rock under various voltage amplitudes. The reliability of the three-dimensional trajectory prediction model is indirectly verified by the laboratory experiment with an electric pulse rock breaking. [ABSTRACT FROM AUTHOR]

Summary: In this article, we investigated a new structure of a protective meander line (ML): a meander microstrip line (MSL) with two passive conductors. The existing theory of ultra‐short pulse (USP) attenuation in MLs is presented for the first time. Based on this theory, we determined the number of decomposed pulses at the output of the MSL line with two passive conductors, and, for the first time, formulated the conditions for pulse decomposition in the line. The folding of the MSL line into non‐core turns was studied in detail. As a result of this article, we proposed a new theory that involves the utilization of additional groups of decomposed pulses for enhanced USP attenuation. These additional groups were thoroughly examined, and the delays of pulses from these groups were defined. This analysis allowed identifying the reason for their appearance. It was revealed that folding the ML into non‐core turns allows further attenuation of the USP amplitude, which increases with the increase of the number of non‐core turns. To validate the obtained simulation results, we performed experimental measurements and obtained good consistency of the results. The N‐norms analysis demonstrated that the combined use of such folding and passive conductors reduces the probability of electrical breakdown, arc discharge, and dielectric breakdown. The maximum USP attenuation at the output was 24.9 dB. As a result of useful signal integrity analysis, it is proposed to use a folded MSL together with a USB 2.0 "Full‐speed" interface with a data transfer rate of 12 Mbit/s. In addition, it is proposed to use such MSLs in DC power circuits. [ABSTRACT FROM AUTHOR]

Introduction. Spark-erosion processing of metals and alloys granules in working liquids is the basis of a several technological processes. Efficiency of energy use in them and parameters of the resulting product largely depend on the accuracy of stabilization and regulation of pulse power in each plasma channel between the granules. To achieve this, until now only the voltage and current of the discharge pulses in the entire layer of granules have been controlled. Problem. The measurement methods, which are used, are not effective enough for monitoring the parameters of individual plasma channels and predicting the size distribution of eroded metals particles at the stage of their formation. The aim of the work is to develop a method for determining the volumes of components of plasma channels in layers of metals granules during their spark-erosion treatment to predict the size distribution of eroded metal particles at the stage of their formation, as well as to simplify the method of spectrometric analysis of the elemental composition of substances surrounding plasma channels for the operational prediction of the chemical composition of resulting products. Methodology. A series of experiments were carried out on spark-erosion processing of Al and Ag granules layers in distilled water. Using a digital camera, images of the plasma channels in them were obtained. Based on the theory of pulsed electrical breakdown of liquid dielectrics, an analysis of the components of plasma channels was carried out. Using the specialized ToupView program, the volumes of equivalent ellipsoids of rotation were determined, approximating the halos of colored radiation likely arising from streamers, as well as the spark cores of plasma channels emitting white light. The shades of the resulting radiation were studied for several metals and working liquids. The obtained data were compared with the known results of spectrometric studies for the same elements excited by similar mechanisms. Results. The theory of discharge-pulse systems for sparkerosion processing of granular conductive media has been developed in the direction of new methods for monitoring the parameters of discharge pulses and predicting the chemical composition and size distribution parameters of eroded metal particles at the stage of their production. An optic-metric method has been developed for determining the volumes of halos and cores of plasma channels. A simplified spectral method for determining the chemical composition of erosion particles based on the shade of the resulting radiation was proposed. Originality. The developed new optic-metric method makes it possible to obtain information about almost every plasma channel, which refines predictions of the size distribution of erosion particles. To implement the method, generalpurpose hardware and specialized software that is freely available are used. The developed method of simplified spectral analysis of excited atoms makes it possible to make preliminary predictions of the chemical composition of the obtained erosion particles already at the stage of their formation without the use of expensive specialized equipment. Practical significance. The ratio of the volumes of halos and cores of plasma channels between Al and Ag granules in distilled water was measured. An analysis of the emission spectra of plasma channel halos between Al, Ag and Cu granules in distilled water, Fe in ethyl alcohol, Ni-Mn-Ga and Ti- Zr-Ni alloys in liquid nitrogen, and Ti-Zr-Ni in liquid argon was carried out. Based on spectrometry data, the resulting shades of these radiations were substantiated and their description in the RGB system is given. [ABSTRACT FROM AUTHOR]

Abstract V‐shaped composite insulator strings exhibit excellent resistance to pollution and wind deviation, resulting in their widespread use in transmission lines. The correlation between inclination angle of the shed surface and pollution flashover voltage can reflect the pollution flashover characteristics of V‐shaped composite insulator strings. Therefore, the relationship between inclination angle and pollution flashover voltage was studied through artificial pollution testing methods, and the relationship between inclination angle and degree of wetting was studied using the method of adding water to increase weight. The results of this study indicated that as the inclination angle increased within the range of 0°–180°, the degree of wetting on the surface of contaminated silicone rubber gradually decreased, whereas the pollution flashover voltage continuously increased. A model of water droplet collision and wetting on the surface of contaminated silicone rubber at different inclination angles was established. This model revealed that the gravity‐induced difference in the wetting states of the surface of contaminated silicone rubber under different inclination angles was responsible for the variation in pollution flashover voltages, with the maximum variation being 116.52%. The results of this study can inform the design and operation of V‐shaped composite insulators.