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We demonstrate a quantitative framework to evaluate a nonradiative capture process with multiphonon emission in a semiconductor/dielectric heterostructure, mediated by a tunneling process. In addition to evanescent tunneling decay, the presence of an internal electric field modifies the relative energy depth of the carrier trap depending on the distance, modulating the overall capture behavior. We quantitatively derive the capture rate based on the parameters of the device structure (gate voltage, threshold voltage, dielectric material thickness, and temperature). We benchmark the formalism for the case of a Si/SiO 2 heterostructure, using an isolated Si dangling bond in α -quartz as a prototype defect in silica. We find that the calculated capture coefficients show a nonmonotonic trend as a function of distance of the defect from the interface, due to countervailing trends in capture barrier and wave-function decay. The predicted capture rates are in reasonable agreement with experimentally measured capture time constants, showing promise for the application of this compact model. [ABSTRACT FROM AUTHOR] more...

Temperature and field dependences of the dielectric permittivity (ɛ) and unipolar electric field-induced strain (S) of PbFe1/2Nb1/2O3, PbSc1/2Nb1/2O3, and 0.91PbFe1/2Nb1/2O3–0.09PbTiO3 solid solution ceramics are studied in the temperature range from 25 to 160 °C. Using these experimental data, both the effective d*33eff = Smax/Emax and differential d*33dif = dS/dE converse piezoelectric moduli are calculated, and (E, T) diagrams were plotted. The possible critical behavior of the converse piezoelectric modulus d*33 and its correlation with the position of the known critical points in the (E, T) diagrams of studied ceramics are discussed. [ABSTRACT FROM AUTHOR] more...

The larger electric or magnetic Purcell factor demonstrates that the structure can be utilized as an electric or magneto-optical emission project. Their simultaneous realization offers the potential for integrated circuits to achieve selective photon sources. In this study, we put forth a proposal for the simultaneous attainment of substantial electrical and magnetic Purcell enhancements. In our hybrid metal–dielectric metasurface, the toroidal dipole (TD) quasi bound states in the continuum mode and the electric dipole (ED) mode are strongly coupled, so the hybrid mode combines the advantages of both, with a large Q factor and a small mode volume. The design implements a Rabi splitting energy of 222 meV between the TD quasi-BIC and ED modes, achieving an electric Purcell factor of 43 and a magnetic Purcell factor of 684, which are greater than those observed for the metal rod and dielectric structure, respectively. This paves the way for the development of high-performance hybrid optoelectronic applications. [ABSTRACT FROM AUTHOR] more...

This study investigates an anti-symmetrically positioned nanophotonic dual-pillar structure, in which the dielectric and vacuum components are evenly distributed along the direction of electron propagation, with each dielectric pillar facing a vacuum region. Our numerical simulation results show that the previously proposed symmetric dielectric grating structure, where dielectric pillars facing each other are alternated with vacuum gaps, is accompanied by a deceleration region, preventing the achievement of high gradients during the acceleration process. By contrast, the anti-symmetric grating structure eliminates the deceleration field and generates a uniformly distributed acceleration field. This requires that the two oppositely directed laser beams crossing the structure in the transverse region must have a phase shift of π in the anti-symmetric case. This structure has significant potential for accelerating sub-relativistic electron beams. In this numerical simulation, the initial energy of the sub-relativistic electron beams is selected as 79 keV. The acceleration gradient provided by the symmetric design for sub-relativistic electrons is approximately 70 MeV/m; however, the anti-symmetric structure can provide a maximum acceleration gradient of up to ∼430 MeV/m. [ABSTRACT FROM AUTHOR] more...

In this paper, a miniaturized and polarization insensitive frequency selective surface filter with large band ratio (BR) is presented. This structure consists of one metal layer and two dielectric layers. The metal layer includes two parts, with the outer square loop providing a lower frequency stopband and the inner pattern providing a higher frequency stopband. The structure has excellent miniaturization characteristics, in particular, the unit size is only 0.054 λ 0 and the thickness is only 0.014 λ 0 , where λ 0 is the wavelength corresponding to the first resonant frequency. Additionally, there is only one layer of metal layer, which greatly reduces the processing complexity and cost. The measurement results show that for TE and TM polarization, the center frequencies of the two stop bands are 2.03 and 18.98 GHz corresponding to a BR of 9.35. It can be used as a spatial dual frequency filter with large frequency band separation. In addition, the proposed structure also possesses advantages such as wideband response, polarization insensitivity, and high angle stability. The simulation results are in good agreement with the measured results. [ABSTRACT FROM AUTHOR] more...

The dielectric constant, although a simplified concept when considering atomic scales, enters many mean-field, electrochemical interface models and constant potential models as an important parameter. Here, we use ab initio and machine-learned molecular dynamics to scrutinize the behavior of the electronic contribution to ɛr(z) as a function of distance z from a Pt(111) surface. We show that the resulting dielectric profile can largely be explained as a sum of the metallic response and the density-scaled water response at the interface. A slight enhancement of the dielectric response close to the surface can be explained by elongated, strongly polarizable orbitals induced by metal/water bonding. In spite of this enhancement, our results suggest the presence of a region with a very low dielectric constant close to the surface (where the orientational dielectric response does not kick in yet), even for water in contact with hydrophilic metallic interfaces. This region will restrict the double layer capacitance to relatively low values even at potentials where dielectric saturation does not play a role yet. This finding has implications on possible interpretations of double layer capacitances, the dependence of surface electric fields on the ion size, and on electrochemical kinetics. [ABSTRACT FROM AUTHOR] more...

In this work, the first fabrication and investigation of normally-off single crystal hydrogen-sterminated diamond MOSFETs with Ga2O3 dielectric has been successfully carried out. 50-nm-thick Ga2O3 was deposited by electron-beam evaporation technique at room temperature. The maximum drain current was −36 mA/mm, which was 164 times larger than previous work. Based on the transfer characteristic curve, the threshold voltage, on/off ratio and extrinsic transconductance were −0.37 V, 2.3 × 107, and 9.8 mS/mm, respectively. The effective mobility of the MOSFET was calculated to be 264.1 cm2/V ⋅s at VGS = − 1 V. This work may significantly promote the application of H-diamond FETs. [ABSTRACT FROM AUTHOR] more...

In this work, the first fabrication and investigation of normally-off single crystal hydrogen-sterminated diamond MOSFETs with Ga2O3 dielectric has been successfully carried out. 50-nm-thick Ga2O3 was deposited by electron-beam evaporation technique at room temperature. The maximum drain current was −36 mA/mm, which was 164 times larger than previous work. Based on the transfer characteristic curve, the threshold voltage, on/off ratio and extrinsic transconductance were −0.37 V, 2.3 × 107, and 9.8 mS/mm, respectively. The effective mobility of the MOSFET was calculated to be 264.1 cm2/V ⋅s at VGS = − 1 V. This work may significantly promote the application of H-diamond FETs. [ABSTRACT FROM AUTHOR] more...

We propose a scheme for dynamically controlling the geometric configurations of honeycomb superlattice plasma photonic crystals (HsPPCs) in dielectric barrier discharge. A rapid transition from a simple honeycomb lattice to diverse HsPPCs has been achieved in ambient air. The HsPPCs exhibit substantial omnidirectional band gaps (OBGs), approximately three times larger than those of simple honeycomb lattices. An experimental verification of the OBGs as well as their frequency shifting with reconfiguration of different HsPPCs has been provided. A phenomenological reaction-diffusion system is developed to unravel the generation mechanism of HsPPCs. The experimental observations are consistent with the numerical simulations. Our approach provides a unique method for manufacturing tunable HsPPCs which significantly enhance the band gap size and improve the photonic properties. [ABSTRACT FROM AUTHOR] more...

This study investigates the impact of dopants on Hf1–xZrxO2-based capacitors for high-performance, hysteresis-free dielectric applications. Control of the crystalline structure of Hf1–xZrxO2 films is crucial for achieving superior dielectric properties. The tetragonal (t) phase of Hf1–xZrxO2 exhibits anti-ferroelectric (AFE) characteristics and shows promise due to its high dielectric constant (κ). However, hysteresis behavior in polarization–voltage sweeps due to AFE behavior presents a significant challenge, primarily due to the high energy loss when implemented in dynamic random-access-memory (DRAM) applications. To achieve hysteresis-free operation, this study focuses on suppressing AFE switching within the DRAM voltage range through Si or La doping in Hf1–xZrxO2 films. Introducing small amounts of Si or La (< 1%) into Hf1–xZrxO2 capacitors effectively diminishes AFE switching by influencing which structural phases are favored: Si doping tends to favor the amorphous phase, while La doping promotes the formation of the t-phase. La doping shows particular promise in enhancing pseudo-linear dielectric performance. ~ 0.9% La-doped Hf0.25Zr0.75O2 capacitors exhibit a markedly improved equivalent oxide thickness (EOT) of ~ 4.8 Å and a reduced leakage current density (Jleak) of ~ 10–7 A/cm2 at 1 V, achieved at back-end-of-line (BEOL) compatible temperatures (< 400 °C). These results demonstrate a promising strategy for advancing energy-efficient high-κ dielectric materials in next-generation memory devices, offering a balanced combination of high capacitance, low leakage current, and BEOL compatibility. [ABSTRACT FROM AUTHOR] more...

(E)-1,1,1,2,2,5,5,6,6,6-Decafluoro-3-hexene (HFO-153-10mczz-E) (CASRN 1256353-26-0) is a volatile liquid proposed for use as a new low global-warming potential dielectric fluid in cooling applications. Workplace exposures are expected to be by inhalation exposure. The substance has low acute inhalation toxicity as indicated by a 4-h inhalation LC50 value of approximately 8000 ppm. A suite of in vitro assays was negative for skin and eye irritation as well as for skin sensitization potential. The chemical did not induce cardiac sensitization up to 5000 ppm. Repeated inhalation exposure in rats for 4 or 13 weeks did not produce any effects attributable to the substance at 3000 ppm, the maximum tested concentration. No indications of developmental or reproductive toxicity were observed in studies in rats, also conducted with a maximum concentration of 3000 ppm. There was no indication of genotoxicity in the Ames assay, an assay with human TK cells, chromosome aberration in cultured human lymphocytes, or an in vivo rat micronucleus assay. The critical study for the development of the 8-hour TWA WEEL is the 13-week inhalation toxicity study with a NOAEC of 3000 ppm (32,400) mg/m3). This inhalation NOAEC was adjusted by application of appropriate uncertainty factors to account for interindividual variability, subchronic to chronic exposure extrapolation and other sources of uncertainty. A WEEL value of 200 ppm (2160 mg/m3) is expected to provide an acceptable margin of safety for potential adverse health effects in workers. [ABSTRACT FROM AUTHOR] more...

Copyright of International Journal of Engineering Transactions C: Aspects is the property of International Journal of Engineering (IJE) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

Electro discharge machining technology is becoming increasingly important in micromachining thanks to its ability to ensure high precision without exerting force on each piece of conductive material. The main applications are injector holes in the automotive sector, the cavities necessary for film cooling in the aeronautical field and also in the electronics and medical fields. Usually, when high aspect micro holes are executed, internal washing through tubular electrodes is advised to facilitate debris evacuation from the machining zone. The internal washing pressure of the dielectric has to be set by the operator. Investigations into the effects of internal washing pressure were made in this work. Dielectric pressure was varied for electrodes of different diameters and materials. The performances were evaluated in terms of machining time, removal rate, tool wear ratio and geometrical indicators. It was found that machining time was connected to the dielectric flow rate, which affected the level of debris contamination in the dielectric. The dielectric flow rate depends on the internal washing pressure, the internal diameter of the electrode and the electrode length. The material removal rate was always higher for the low flow rates for all of the electrode diameters and materials that were tested. The electrode wear was also influenced by the dielectric flow. With low pressures, a larger amount of debris remained in the machining zone, and the change in the dielectric characteristics made the formation of discharge easier. This phenomenon improved the material removal rate but also increased the electrode wear. A connection between the contamination level and the overcut was also found. A visual investigation of both the electrode tip and the internal hole surfaces supported the assumption about the effects of debris on drilling performance. [ABSTRACT FROM AUTHOR] more...

Maintaining high charge/discharge efficiency while enhancing discharged energy density is crucial for energy storage dielectric films applied in electrostatic capacitors. Here, a nano-submicron structural film comprising ferroelectric material P(VDF-HFP) and linear dielectric material PMMA has been flexibly designed via the electrospinning process. Nano-submicron structure enables the film to maximize the ferroelectric material component and obtain improved dielectric performance without sacrificing breakdown strength and charge/discharge efficiency. As a result, the 40%-420 nm PMMA-P(VDF-HFP)@PMMA sample achieved an discharged energy density of 13.72 J/cm³ at a field of 740 kV/mm, with an impressive charge/discharge efficiency of 80%. This work presents a composite dielectric film that excels in breakdown strength, discharged energy density, and charge/discharge efficiency, offering a strategy for designing reliable, industrial-grade energy storage dielectrics. The authors prepare an all-organic dielectric film with a nano-submicron surface layer via electrospinning technology, achieving a simultaneous improvement in the discharged energy density and charge/discharge efficiency. [ABSTRACT FROM AUTHOR] more...

Solid-state cooling technology based on electrocaloric effect (ECE) has attracted worldwide attention due to its high efficiency, environmental benign nature, and cost effectivity. Although different forms of EC materials, i.e., ceramic bulk, multilayer ceramic capacitor, thin film, etc., have applied for EC applications, the impact of different structures on EC performance has not been thoroughly determined. In this study, ceramic bulks and multilayer ceramic capacitor (MLCC)-structured EC materials are directly compared with the same composition of 0.92Pb(Mg1/3Nb2/3)O3-0.08PbTiO3(PMN-8PT). In order to further figure out the performance improvement caused by geometric design, the dielectric layer thicknesses and layer numbers of MLCC structures were varied, while the same effective working volume was maintained. Both indirect and direct measurements were utilized for comparative EC performance analysis of ceramic bulk and multilayer structures. It was observed that MLCC samples with 6 dielectric layers exhibited an enhanced breakdown strength of 142 kV cm−1, achieving enhanced electrocaloric performance of ΔS = 0.979 J kg−1 K−1 and ΔT = 1.285 K. These results indicate that when the effective cooling volume maintains equivalent in ferroelectric materials, the MLCC samples with reduced dielectric layer thickness exhibit an enhancement in the EC performance. It could be concluded that the MLCC structure would be beneficial for high EC performance, especially in terms of practical applications. [ABSTRACT FROM AUTHOR] more...