Search

The flow features and heat transfer enhancement of electro-thermo-convection (ETC) in dielectric liquids with residual conductivity between concentric electrodes are numerically studied based on an injection-conduction model. The strongly coupled flow field, electric field, and positive/negative charge density of the ETC system are solved numerically based on the finite volume framework of OpenFOAM®. The total variation-diminishing algorithm is adopted to handle the complex nonlinearity of the positive/negative charge transport equations. The bifurcation of plentiful flow states that are characterized by variable plumes and vortex pairs in the ETC system is investigated. It is discovered that the residual conductivity postpones the beginning of ETC flow, inhibits the convection intensity, and also diminishes heat transfer of the ETC system. In addition, the transition sequences of ETC flow are also influenced by residual conductivity. A higher residual conductivity suppresses the occurrence of different intermediate steady-states. Three different transition sequences of steady ETC states at different Rayleigh numbers (Ra) are identified. The critical point where the ETC flow bifurcates to S8 is postponed at higher Ra. And the ETC system is more prone to chaos in a system of higher Ra. The periodicity of the ETC system is analyzed and found that Ra has little influence on the periodicity. [ABSTRACT FROM AUTHOR]

In this study, a gallium oxide (Ga2O3) U-groove gate metal-oxide-semiconductor field-effect transistor (UMOSFET) with a high breakdown voltage (BV) is proposed. Through TCAD simulation, both forward and reverse electrical characteristics are comprehensively investigated. The integration of traps within the current blocking layer (CBL) is suggested to enable effective current blocking. Furthermore, to optimize the BV, the introduction of oxide dielectric pillars on either side of the drift layer is implemented to enhance the potential distribution during breakdown. The forward and reverse electrical characteristics of the device at different temperatures are also investigated. Additionally, by conducting simulation optimizations of different doping concentrations in the drift layer, CBL layer thickness, and trap concentrations, notable achievements are realized, which include a high BV of 865.2 V, low threshold voltage of 2.587 V, and low specific ON-resistance of 19.2 mΩ·cm2. This study presents a novel structural design to foster the potential application and development of Ga2O3 electronic devices. [ABSTRACT FROM AUTHOR]

High dielectric constants with less dielectric loss composites is highly demandable for technological advancements across various fields, including energy storage, sensing, and telecommunications. Their significance lies in their ability to enhance the performance and efficiency of a wide range of devices and systems. In this work, the dielectric performance of graphene oxide (GO) reinforced plasticized starch (PS) nanocomposites (PS/GO) for different concentrations of GO nanofiller was studied. The surface morphology, and chemical and structural properties of the PS/GO nanocomposites were investigated by field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectrometry (FTIR), and X-ray diffractometer (XRD). The FESEM study showed a uniform dispersion of the GO nanofiller in the nanocomposites. The XRD analysis showed a reduction in d-space due to the incorporation of GO nanofiller in the nanocomposites. The FTIR data exhibits the formation of hydrogen bonds among PS and GO nanofillers, suggesting the presence of strong interaction between them. The dielectric properties of the nanocomposites were studied at room temperature in the frequency range 100 Hz‒1 MHz. The dielectric constant was found to improve due to the incorporation of GO. This composite nanomaterial also provides low dielectric loss at low frequency. Moreover, an increasing trend is observed for the AC conductivity of the composites. From the complex impedance study, the changes in various impedances with low to high-frequency ranges have been calculated and explained in the equivalent circuit diagram. The complex impedance spectra analysis shows the change in resistance and constant phase element (CPE): grain boundary resistance, R2 decreases from 4.3 KΩ to 1.9 KΩ, and CPE increases from 0.59 μF to 0.72 μF for PS/GO (0.5%) nanocomposite. This study will provide a potential route for the fabrication of biocompatible dielectric device fabrication. [ABSTRACT FROM AUTHOR]

Based on the mechanical regulation mechanism, a super‐low‐frequency (SLF) reconfigurable magnetoelectric (ME) antenna is proposed for underwater frequency‐hopping communication. By constructing the mechanical model of the ME antenna loaded with an adjustable spring, the antenna's working frequency is predicted to be tuned in an extensive dynamic range from 148 to 331 Hz by changing the states of a loaded spring. The experiment is implemented in the frequency‐response test platform and the practical communication system using the minimum shift keying modulation. The former experiment well validates the tunable frequency response of the reconfigurable ME antenna, while the latter successfully achieves the information transmission at different working frequencies. The proposed SLF reconfigurable ME antenna serves as a potential candidate for under‐water frequency‐hopping communication. [ABSTRACT FROM AUTHOR]

Field‐effect transistor (FET)‐type pressure sensor offers excellent amplification and signal conversion functionality as a switching device, and it has the capability to integrate tactile sensors by constructing active‐matrix arrays with low crosstalk. However, conventional FET‐type pressure sensors either have a complex device layout with additional components, such as pressure‐sensitive elastomer, attached to the source/drain electrodes, or the method of modulating the gate dielectric can lead to dielectric breakdown and device failure. Additionally, the deformation of the elastomer limits response speed and causes differences in early and late response characteristics. In this article, a facile structure pressure‐sensing thin film transistor (TFT) that modulates the channel conductivity by cellulose/single‐wall carbon nanotube (SWCNT) composite is reported, ensuring a simple layout without damaging the device. The fabricated cellulose/SWCNT‐based pressure‐sensing TFT exhibits a change in the on/off current ratio from 2.75 × 103 to 2.0 × 104 in response to pressure with high linearity (R2 = 0.9935) and maintains durable performance over 2000 loading‐unloading cycles. Additionally, the sensor shows a fast response time of less than 8 ms. A practical concept of sensing circuits is demonstrated based on pressure‐sensing TFTs for integration into display driving circuits, enabling accurate pressure sensing using only the signal to drive the display. [ABSTRACT FROM AUTHOR]

In this study, a passive control strategy of inductive power transfer (IPT) using ferroelectric multilayer ceramic chip capacitors (MLCCs) is presented. The required system parameters, i.e., ferroelectric hysteresis, frequency of the IPT, and voltage range across the MLCCs are reported. The receiver circuit consists only of a parallel resonant circuit, a halfwave rectifier and a load; the passive control of the IPT is achieved exclusively by the nonlinear properties of the ferroelectric MLCCs. The stabilization of the secondary output voltage ULoad at constant load is experimentally evaluated for an inductive coupling factor k between 10 % and 30 % for three nonlinear MLCCs #1, #2 and #3. With our proposed passive control strategy ULoad is maintained at -1.2 % and +0.6 % around a median value of 17.3 V (17.1 - 17.4 V) for k ∈ [20 %, 30 %] using MLCC #1, ±0.9 % around a median value of 11.2 V (11.1 - 11.3 V) for k ∈ [10 %, 18 %] using MLCC #2, and -1.6% and +2.6 % around a median value of 5.03 V (4.95 - 5.16 V) for k ∈ [16 %, 30 %] using MLCC #3. The proposed control principle is particularly advantageous for highly miniaturized microimplants, as it allows IPT control without additional semiconductors, sensors and vulnerable communication channels. [ABSTRACT FROM AUTHOR]

In dealing with the increasing power dissipation of electronic systems with increasing integration density, a field‐effect transistor (FET) with steep switching slope that overcomes the thermionic limit is vital to achieve low‐power operations. Here, we report two types of threshold switching (TS) FETs based on 2D Van der Waals heterostructures by virtue of the abrupt resistive switching of the hexagonal boron nitride (hBN) TS device. The common hBN dielectric layer functions as the switching medium for the TS device and the gate dielectric for the 2D FET enabling seamless integration of the hBN TS device and baseline 2D FET. TS FET in source configuration by connecting the TS device to the source terminal of the 2D FET offers an ultralow average subthreshold swing (SS) of 1.6 mV/dec over six decades of drain current at room temperature and suppressed leakage current. TS FET in gate configuration by connecting the TS device to the gate terminal of the 2D FET also exhibits steep switching slope with ultralow SS of 10.6 mV/dec. The proposed compact device structures integrating 2D FET and TS device provide a potential approach of monolithic integration toward next‐generation low‐power electronics. [ABSTRACT FROM AUTHOR]

The BaNb2V2O11 microwave dielectric material, synthesized using a solid-state process, was proposed for utilization as a temperature compensator in LTCC applications. XRD analysis indicated that all samples revealed a trigonal structure of the BaNb2V2O11 phase with the R3̅m (166) space group. Influence of lattice energy and bond energy on the dielectric characteristics were investigated. Correlation between the Full Width at Half Maximum (FWHM) of the primary Raman peak at 917 cm⁻1 and the Q × f value was also analyzed. The sample sintered at 860 °C exhibited remarkable microwave dielectric properties, including a high relative permittivity (εr) of 88.7, a high Q × f value of 2100 GHz, and a significantly positive temperature coefficient of resonant frequency (τf) of + 602.4 ppm/°C. This notably large positive τf value makes it an effective τf compensator. Furthermore, the high εr value indicates its suitability for use in decoupling devices or as dielectric resonators in 5G base stations. [ABSTRACT FROM AUTHOR]

Silicon nitride (SiNx) is used for device passivation and capacitance dielectric in GaN monolithic microwave integrated circuits. However, this is a conflicting requirement as passivation requires SiNx to cause tensile strain, and capacitance dielectric primarily demands a high breakdown voltage and large dielectric constant for SiNx, leading to a damaged AlGaN surface during deposition. Two independent SiNx depositions under two different conditions (silicon‐ and nitrogen‐rich) are usually carried out to meet both requirements. Herein, a solution for a unified deposition through interfacial strain analysis on an AlGaN/GaN heterostructure grown on 6H‐SiC imposed by thin film silicon nitride (SiNx), deposited using inductively coupled plasma chemical vapor deposition system is proposed. The strain analysis is done using Raman spectroscopy. The surface morphology of the SiNx is studied using atomic force microscopy. The breakdown characteristics are ascertained from measurements on high electron mobility transistors and metal–insulator–metal capacitors. [ABSTRACT FROM AUTHOR]

A rapid and reliable quench detection is vital for high current superconducting magnet system to prevent irreversible damage to a magnet by the quench phenomenon. The method for detecting the occurrence of a resistive transition has been widely adopted in the superconducting magnet. In the case of the voltage monitoring by means of dedicated taps, the electron quench detection device (EQDD) conversion unit, which converts detected high voltages into voltage-drop signal, should be required in the superconducting high field magnet. The power source of traditional quench detecting system, which can monitor for superconducting magnet with middle power operation, is supplied through the power transformer since the transformer can provide galvanic isolation between circuits. On the other hand, in the case of the super high magnet systems such as Korea Superconducting Tokamak Advanced Research and International Thermonuclear experimental reactor, since the maximum operation current and voltage of the super high field magnet keep over 60 kA and 50 kV DC, a passive component, which has strong an isolation device and high dielectric resistor qualities, has been required in the super high field magnet. If the power transformer is adopted in the super high field magnet, it can cause high cost for volume capacity since it needs for higher dielectric resistance value over 500 MΩ. Authors proposed the wireless resonance antenna and multi-receiver coils which can keep high level of dielectric resistance value with stability. As well as, the wireless power charging unit can reduce system volume due to multi-charging receivers for one antenna. In this study, authors investigated the effect of inserted resonator (Sx) coil between antenna and receiver coils, as well as, evaluated the electric field and magnetic field among the resonance coils under 300 W 370 kHz RF power generator since the strong electro-magnetic fields by the resonance coils can affect the electron devices inside of the EQDD module. [ABSTRACT FROM AUTHOR]

Herein, stacked layers of Nb2O5 structured with platinum nanosheets were fabricated to handle multifunctional electro-optic operations. The stacked layers of Nb2O5/Pt/Nb2O5 (NPN) were prepared by the ion coating technique and exhibited an amorphous structure. A remarkable increase in light absorption by more than 480% was achieved via the insertion of Pt nanosheets between layers of Nb2O5. Pt nanosheets with thicknesses of 50 nm and 100 nm successfully increased the electrical conductivity of the NPN layers by five and eight orders of magnitude, respectively, without losing transparency. This feature makes the NPN stacks suitable for transparent conducting oxide applications. The insertion of Pt nanosheets between layers of Nb2O5 also converted the conductivity from p- to n -type. In addition, NPN stacked layers exhibited highly enhanced dielectric properties, demonstrating an increase in the dielectric constant by 190%, making the NPN stacked layers suitable for use in the design of high-κ gate dielectric devices. Moreover, when treated as optical filters, Drude–Lorentz fittings of the dielectric spectra showed that Pt nanosheets increased the free carrier density and the plasmon frequency. The terahertz cutoff frequency of the NPN devices steadily increased with increasing Pt nanosheet thickness. The terahertz cutoff frequency for NPN optical filters comprising a 100-nm-thick layer of Pt displayed values of 7.5 THz and 5.0 THz in the infrared and visible light ranges. The NPN stacks have potential for use in terahertz applications. [ABSTRACT FROM AUTHOR]

Cellulose-based nanomaterials are fascinating renewable biosystems, yet low thermal conductivity and dielectric permittivity often limit their potential applications in flexible electronics. We report dielectric properties of composite films prepared by vacuum filtration or solvent casting method from the native (CNF) or carboxylated (TCNF) cellulose nanofibrils and high electrically and thermally conductive 2D titanium carbide (Ti3C2Tx) MXenes. Measurements over broad frequency and temperature ranges revealed the influence of preparation method and type of nanofibrils matrix on the overall dielectric response, as well as a notable impact of absorbed water, particularly on the cellulose's secondary β and γ relaxations. A detailed investigation of material with the lowest amount of impurities, vacuum-filtered MXene/CNF composites, confirmed that the dielectric response follows the predictions of the percolation theory. The resulting strong enhancement of the dielectric permittivity on increasing MXene content demonstrates the potential of developed composites for applications in eco-friendly dielectric and piezoelectric devices. [ABSTRACT FROM AUTHOR]

Atomic description of electrochemical systems requires reactive interaction potential to explicitly describe the chemistry between atoms and molecules and the evolving charge distribution and polarization effects. Calculating Coulomb electrostatic interactions and polarization effects requires a better estimate of the partial charge distribution in molecular systems. However, models such as reactive force fields and charge equilibration (QEq) include Coulomb interactions up to a short-distance cutoff for better computational speeds. Ignoring long-distance electrostatic interaction affects the ability to describe electrochemistry in large systems. We studied the long-range Coulomb effects among charged particles and extended the QEq method to include long-range effects. By this extension, we anticipate a proper account of Coulomb interactions in reactive molecular dynamics simulations. We validate the approach by computing charges on a series of metal-organic frameworks and some simple systems. Results are compared to regular QEq and quantum mechanics calculations. The study shows slightly overestimated charge values in the regular QEq approach. Moreover, our method was combined with Ewald summation to compute forces and evaluate the long-range effects of simple capacitor configurations. There were noticeable differences between the calculated charges with/without long-range Coulomb interactions. The difference, which may have originated from the long-range influence on the capacitor ions, makes the Ewald method a better descriptor of Coulomb electrostatics for charged electrodes. The approach explored in this study enabled the atomic description of electrochemical systems with realistic electrolyte thickness while accounting for the electrostatic effects of charged electrodes throughout the dielectric layer in devices like batteries and emerging solid-state memory. [ABSTRACT FROM AUTHOR]

We report the pulsed laser deposition (PLD) of nanocrystalline/amorphous homo-composite BaTiO3 (BTO) films exhibiting an unprecedented combination of a colossal dielectric constant (εr) and extremely low dielectric loss (tan δ). By varying the substrate deposition temperature (Td) over a wide range (300–800 °C), we identified Td = 550 °C as the optimal temperature for growing BTO films with an εr as high as ~3060 and a tan δ as low as 0.04 (at 20 kHz). High-resolution transmission electron microscopy revealed that the PLD-BTO films consist of BTO nanocrystals (~20–30 nm size) embedded within an otherwise amorphous BTO matrix. The impressive dielectric behavior is attributed to the combination of highly crystallized small BTO nanograins, which amplify interfacial polarization, and the surrounding amorphous matrix, which effectively isolates the nanograins from charge carrier transport. Our findings could facilitate the development of next-generation integrated dielectric devices. [ABSTRACT FROM AUTHOR]

This study focuses on the dielectric responses of the B 3 6 nano-Borophene lattice, using Monte Carlo simulations. It explores the impact of various parameters, including temperature, the J SS coupling interaction, the crystal field D, and the impact of the longitudinal electric field E Z , on the dielectric characteristics of nano-Borophene. Simulation study results show that these parameters significantly influence the blocking temperature T B and modify the shape and area of the electrical hysteresis cycle. This research can make an important contribution to the understanding of dielectric phenomena, which is essential in fields such as high-temperature dielectric devices and other advanced technological applications. [ABSTRACT FROM AUTHOR]

Controlled cross‐linking of polymer dielectric poly (4‐vinylphenol) (PVP) is demonstrated as an effective tool in enhancing the performance of flexible organic synaptic transistors (OSTs). Investigation of variation of concentration of the cross‐linking agent methylated poly (melamine‐co‐formaldehyde) (PMCF) in PVP in bilayer combination with high‐k hafnium oxide (HfO2) as gate dielectric in devices shows that the lower concentration of cross‐linking agent results in better memory performance. OSTs with 26% PMCF concentration in PVP (by mass) exhibit excellent memory performance with memory window > 4 V for VGS sweep of ±5 V, static retention of ≈104 s, dynamic retention for 500 cycles, and ≈125 continuous program/erase cycles. Pulse paired facilitation with relaxation time constants of 370 and 4670 ms respectively for slow and rapid phases with regulating modulation amplitude of ≈1 resemble a biological synapse. Through excitatory post synaptic current characteristics, spike timing dependant plasticity and spike voltage dependant plasticity are clearly observed, with low energy consumption per spike on the order of 10 pJ. Further, by leveraging the intricate interconnected data transfer and computation phenomenon, "AND" logic is effectively implemented using these OSTs. These exciting results may open up new directions toward the development of hardware for neuromorphic computing. [ABSTRACT FROM AUTHOR]

In recent years, machine learning (ML) and deep learning (DL) have been widely used to break the metasurface’s performance ceiling. However, the existing data‐driven ML and DL methods usually require the availability of vast amounts of training data to ensure their stable and accurate performance. The process of acquiring these data is high‐cost due to the need for numerous full‐wave electromagnetic (EM) simulations. Here, we  propose a low‐cost surrogate model to generate these data efficiently. The proposed model employs microwave network theory to separate meta‐elements into four independent components. Through integration with transmission line theory, we  derive the EM responses of meta‐elements using analytical representation with the active device equivalent impedance and dielectric as design variables. Two typical phase‐modulation active meta‐elements are employed to verify the accuracy of our  macromodel in comparison with full‐wave EM simulations. Based on the developed macromodel, the superior prediction ability is further presented to illustrate the performance of meta‐elements with various active devices and dielectric substrates. The proposed macromodel is a feasible and general method to rapidly obtain the necessary training data of active meta‐elements, which holds a great potential to significantly reduce the designing time of ML and DL models for the active metasurfaces. [ABSTRACT FROM AUTHOR]

Copyright of Dokuz Eylul University Muhendislik Faculty of Engineering Journal of Science & Engineering / Dokuz Eylül Üniversitesi Mühendislik Fakültesi Fen ve Mühendislik Dergisi is the property of Dokuz Eylul Universitesi Muhendislik Fakultesi Fen ve Muhendislik Dergisi 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.)

As the competition intensifies in enhancing the integration and performance of integrated circuits, in accordance with the famous Moore's Law, higher performance and smaller size requirements are imposed on the dielectric layers in electronic devices. Compared to vacuum methods, the production cost of preparing dielectric layers via solution methods is lower, and the preparation cycle is shorter. This paper utilizes a low-temperature self-exothermic reaction based on the solution method to prepare high-performance Al2O3 dielectric thin films that are compatible with flexible substrates. In this paper, we first established two non-self-exothermic systems: one with pure aluminum nitrate and one with pure aluminum acetylacetonate. Additionally, we set up one self-exothermic system where aluminum nitrate and aluminum acetylacetonate were mixed in a 1:1 ratio. Tests revealed that the leakage current density and dielectric constant of the self-exothermic system devices were significantly optimized compared to the two non-self-exothermic system devices, indicating that the self-exothermic reaction can effectively improve the quality of the dielectric film. This paper further established two self-exothermic systems with aluminum nitrate and aluminum acetylacetonate mixed in 2:1 and 1:2 ratios, respectively, for comparison. The results indicate that as the proportion of aluminum nitrate increases, the overall dielectric performance of the devices improves. The best overall performance occurs when aluminum nitrate and aluminum acetylacetonate are mixed in a ratio of 2:1: The film surface is smooth without cracks; the surface roughness is 0.747 ± 0.045 nm; the visible light transmittance reaches up to 98%; on the basis of this film, MIM devices were fabricated, with tested leakage current density as low as 1.08 × 10−8 A/cm2 @1 MV and a relative dielectric constant as high as 8.61 ± 0.06, demonstrating excellent electrical performance. [ABSTRACT FROM AUTHOR]

Polymer dielectric materials have recently attracted attention for their versatile applications in emerging electronic devices such as memory, field-effect transistors (FETs), and triboelectric nanogenerators (TENGs). This review highlights the advances in polymer dielectric materials and their integration into these devices, emphasizing their unique electrical, mechanical, and thermal properties that enable high performance and flexibility. By exploring their roles in self-sustaining technologies (e.g., artificial intelligence (AI) and Internet of Everything (IoE)), this review emphasizes the importance of polymer dielectric materials in enabling low-power, flexible, and sustainable electronic devices. The discussion covers design strategies to improve the dielectric constant, charge trapping, and overall device stability. Specific challenges, such as optimizing electrical properties, ensuring process scalability, and enhancing environmental stability, are also addressed. In addition, the review explores the synergistic integration of memory devices, FETs, and TENGs, focusing on their potential in flexible and wearable electronics, self-powered systems, and sustainable technologies. This review provides a comprehensive overview of the current state and prospects of polymer dielectric-based devices in advanced electronic applications by examining recent research breakthroughs and identifying future opportunities. [ABSTRACT FROM AUTHOR]

The reliability issues in silicon carbide (SiC)-based devices with gate dielectric formed through heat oxidation are significant factors limiting their application in power devices. Aluminum oxide (Al2O3) was chosen as a high-k material to form the gate oxide layer on top of a SiC substrate. Atomic layer deposition (ALD) was used to fabricate an Al2O3/4H-SiC heterostructure, and the quality of the ALD Al2O3 layer was examined by XPS and electrical experiments. The XPS analysis suggests that the created heterojunction is a type-I heterojunction with ΔEC = 1.89 eV and ΔEV = 1.83 eV. Metal-insulated semiconductor structures with upper and lower Al electrodes were prepared for investigating leakage current and breakdown voltage characteristics. The leakage current density and breakdown electric field of an MOS capacitor structure with an Al2O3/4H-SiC heterojunction are ∼10−10 A/cm2 and 9.3 MV/cm, respectively. The interfacial defect density (Dit) near the conduction band of the MOS capacitive structure with the SiC substrate is 1.44 × 1012 eV−1 cm−2, while the interface charge (Neff) of the oxide layer of this sample can also be controlled at a level of 1011 cm−2. The Al2O3/SiC structure fabricated in this work exhibits superior electrical performance compared to the heterostructure based on the Si substrate and other relevant heterostructures documented in previous studies. [ABSTRACT FROM AUTHOR]

The enhancement-mode AlGaN/GaN metal insulator semiconductor high electron mobility transistor (MIS-HEM) with recessed gate structure is comprehensively studied by using Silvaco TCAD software. The effects of etching depth of AlGaN barrier layer, gate length, sort and thickness of gate dielectric layer on device performance are explored. The outcomes from the simulation indicate that the enhanced device is capable of attaining a threshold voltage of +1 V, a substantial drain saturation current of 1.38 A/mm, and an elevated peak transconductance of 498 mS/mm. It has been observed that the gate recess depth substantially boosts the transconductance, achieving a maximum value of gmmax at 498 mS/mm.The value significantly surpasses that exhibited by the traditional AlGaN/GaN MIS-HEMT. The threshold voltage of Al0.18Ga0.82N TBL recessed gate MIS-HEMT is +1 V. Furthermore, in comparison to the conventional MIS-HEMT device, the drain saturation current experiences an augmentation by about 9.5%. TCAD simulation results show that this HEMT structure is more effective than conventional HEMT in terms of enhanced mode operation and device parameters. [ABSTRACT FROM AUTHOR]

High dielectric constant and ultra-low dielectric loss are important for electronic device applications of dielectrics. In this work, the novel ceramic BaNd 2 Ti 4 O 12 , synthesized via solid-state reaction, exhibits remarkable dielectric stability, with excellent dielectric properties (ε ′ = 117 and tan δ = 6.27 × 10−4, at 1 kHz) and high dielectric strength (E b = 260 kV/cm). By exploring its polarization behavior and loss mechanisms at low frequencies for the first time, we found that the sustained high dielectric constant is attributed to the synergy of defect dipole polarization and interface polarization, while the observed exponential increase of dielectric loss is primarily caused by the conduction loss, with a minor contribution from the anelastic relaxation loss. In the low-temperature range of 50∼350 °C, the relaxation behavior is governed by the aggregation and subsequent thermal ionization of the oxygen vacancies, whereas at temperatures above 350 °C, it is predominated by the long-range motion of the doubly ionized oxygen vacancies. These findings provide valuable insights for the potential electronic device applications of BaNd 2 Ti 4 O 12. [ABSTRACT FROM AUTHOR]

Perovskite LaAlO3, LaAlO3:Dy3+ and LaAlO3:Dy3+:Bi3+(1mol%) is a nano substance prepared through a chemical combustion process using sugar as a fuel. Powder X-ray Diffraction (PXRD) and Transmission Electron Microscopy (TEM) confirm an irregularly shaped non-polycrystalline nature with a Rhombohedral phase of space group R3m having crystallite size ranging between 24-26 nm. Scanning electron microscopy and energy dispersive spectra confirm the porous, dumbbell-shaped morphology and its constituents. The Fourier Transform Infrared (FTIR) spectra peaks between 840cm-1 to 400cm-1 proving the presence of metal oxide and a peak located at 1380.0cm-1 ascribed to carboxylate ions vibrational modes present in the studied sample. The dielectric studies show a higher and increased dielectric constant for doped and codoped samples than the host sample, hence it may be used as storage devices. Cole-Cole plots for conductivity studies show semicircles at high frequencies indicating the grain effect. There was a continuous increase in the radius of the semicircle of the Cole-Cole plot, for host, doped and codoped samples indicating the increase in the material's resistance. Therefore, the prepared material finds applications in devices like Complementary Metal Oxide Semiconductor (CMOS). [ABSTRACT FROM AUTHOR]

The enhancement of plasma generation in atmospheric pressure dielectric barrier discharge (DBD) is gaining increasing interest for various plasma applications. In this paper, the effect of surface charges moving with the rotating dielectric plate on improving the generation of streamer channels is investigated by a statistical analysis of electrical measurements, optical diagnostics, and numerical simulation in a needle-plate DBD device with a rotating dielectric plate. Results suggest that rotating the dielectric plate can improve the spatiotemporal distribution of streamer channels by inducing a bending of the streamer channels and an increase in the number of discharges. Statistical results show that the number of current pulse and discharge energy are increased by 20% and 47%, respectively, at the rotating speed of 160 rps (revolution per second). Based on the interaction between the applied electric field and the electric field induced by surface charges, a formula is proposed to govern the effect of rotating the dielectric plate on the discharge energy and streamer bending. To further understand the mechanism of the influence of rotating the dielectric plate on plasma properties, a 2D fluid model is implemented, and the reduced electric field and streamer propagation are analyzed. Results show that the effective transfer and reuse of surface charges play an important role in the enhancement of plasma generation. [ABSTRACT FROM AUTHOR]

More than a decade of active electrocaloric (EC) material research has produced several EC materials that exhibit a giant electrocaloric effect (ECE) at high electric fields, which is assured by direct measurement. These EC materials have enabled the demonstration of EC cooling devices, which exhibit temperature lifts of more than 10 K. These research and development efforts have revealed the critical importance of electrical breakdown, which is common in all electric and dielectric materials and devices under high voltages and electric fields. In general, the electric field for reliable device operation of dielectrics has to be less than 25% of the typical electric breakdown strength. To realize EC cooling devices with competitive performance requires advanced EC materials that generate large ECE (ΔT > 5 K) under these low electric fields. Double-bond (DB) defect modified P(VDF-TrFE-CFE) relaxor polymers, as reported recently, generate large ECE under low electric fields without any fatigue effects even after 1 × 106 field cycles. These relaxor ferroelectrics promise to meet the application challenge. A closely coupled experimental and theoretical study of EC materials will undoubtedly lead to advanced EC materials that generate large ECE at low electric fields beyond the DB modified relaxor polymers. This will result in practical and high-performance EC coolers, which are environmentally benign, compressor-free, and highly efficient. [ABSTRACT FROM AUTHOR]

In this article, we focus on the plasma seed interaction and more specifically-on the feedback exerted by the seeds on the plasma properties. Dormant Arabidopsis seeds with different water contents (WC), namely 3%DW, 10%DW and 30%DW were exposed to cold ambient air plasma (C2AP) generated in a dielectric barrier device (DBD). It is found that increasing WC enhances the capacitive current of the DBD, generates a greater number of low energy streamers (characterized by current peaks lower than 10 mA) that preferentially interplay with the seeds. Since the resistive and capacitive components of the seeds modify the C2AP electrical properties, impedance measurements (also called LCRmetry) have been carried out to measure their main dielectric parameters before/after plasma exposure (seeds resistance, capacitance, complex relative permittivity, tangent loss and conductivity). It appears that WC significantly changes dielectric losses at low frequencies (<1 kHz) due to polarization relaxation of the polar molecules (i.e. water). LCRmetry further reveals that C2AP does not substantially alter seeds dielectric parameters, i.e. it neither adds or removes significant amounts of new materials, meaning that the relative starch, protein and lipid contents remain essentially unaffected. However, it cannot be discounted that some bulk properties of the Arabidopsis seeds may be modified, especially regarding their porosity. This characteristic could facilitate penetration of plasma-generated reactive oxygen species into the internal seed tissues, leading to the grafting of oxygenated groups. To corroborate this theory, water sorption isotherms have been achieved on Arabidopsis seeds and fitted with four thermodynamic models, including the Brunauer–Emmett–Teller model and the Generalized D'Arcy and Watt model. It is demonstrated that C2AP primarily strengthens water-seed affinity by modifying molecular interactions rather than changing the seed's moisture layer. This occurs despite a potential decrease in the number of adsorption sites, indicating a significant increase in overall seed hydrophilicity after plasma treatment. [ABSTRACT FROM AUTHOR]

The method of evaluating the resonant frequencies of multilayered resonator containing uniaxial anisotropic dielectrics is presented. The detailed solution of Maxwell's equations for such a structure by means of the radial modes matching method for TE0mn modes is given. The results of calculations using developed and launched computer program are given. Results of calculations are compared with those obtained by other method using CST simulator. These results are in close agreement, which proves the correctness of the method. The developed solution, and the software program can be used to measure the tensor permittivity of dielectrics. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVF2) has emerged as a promising material for dielectric applications due to its excellent electrical and mechanical properties. However, maximizing the electroactive β-phase content in PVF2 is crucial to enhance its dielectric performance. In this study, we propose a facile method to enhance the β-phase content in PVF2 by doping gold nanoparticles (n-Au) (0–5 wt%) in the form of nanocomposites. The X-ray diffraction (XRD) patterns obtained for the annealed Au-PVF2 films of Au-content specifically at 2 and 5 wt% exhibit a characteristic (200) peak of β-PVF2, whereas non-annealed samples show diffraction peaks of (020) and (110) from a nanocrystalline α-PVF2 phase. The Fourier transformed infrared spectroscopy (FTIR) study illustrates distinct absorption bands at 483 and 510, 834, and 880 cm−1 characterize the formation of β-PVF2 phase in respective Au-PVF2 films compared to pure PVF2 film which still contains IR bands of α-PVF2 after annealing. Unambiguously, the gold inclusions induce a α → β-PVF2 phase transformation. An enhanced dielectric constant value (εr-value), as large as 70 (i.e., an order of larger magnitude of the basic PVF2 value), is found at low frequencies near 100 Hz after an optimized 2.0 wt% Au loading of a percolation threshold value. Our results reveal that these nanocomposites hold significant potential for applications in high-performance dielectric devices and energy storage systems requiring superior dielectric properties. [ABSTRACT FROM AUTHOR]

Tunnel field effect transistors (TFETs) are known for lower power requirements than MOSFETs due to their utilization of the band-to-band tunneling mechanism, along with low subthreshold swing (SS). The traditional TFET suffers from low drain current; however, drain current can be improved by modifying the TFET device structure. In this work, a 2-D heterojunction (Ge/Si) vertical-tunnel field effect transistor (HV-TFET) with an optimal design is proposed in which the source region is made of germanium (Ge) due to its low bandgap, while silicon (Si) is used for the regions of drain and channel to mitigate leakage current because of its wider bandgap. The goal of this work is to achieve improved switching by enhancing the ON-state current (ION) and reducing the OFF-state current (IOFF). The currents obtained have values of 1.19 × 10−3 A/µm and ~ 10−15 A/µm, respectively, and therefore the ION/IOFF ratio is ~ 1011 for the device proposed in this paper. Three different dielectric gate oxide materials are used for studying the effect of dielectric materials on the device parameters. Hafnium oxide (HfO2) is found to offer the best results when used for gate oxide, and hence is used in the proposed device structure. Also, this work examines a number of electrical parameters of the device structure due to changes in physical device parameters. The results are produced using the Sentaurus TCAD tool to confirm the suitability of the proposed device for use in circuit applications with low-power strategies. [ABSTRACT FROM AUTHOR]

We propose a technique for the wafer-level testing of the gate dielectrics of metal–insulator–semiconductor (MIS) devices by the high-field injection of electrons into the dielectric using a mode of increasing injection current density up to a set level. This method provides the capability to control a change in the charge state of the gate dielectric during all the testing. The proposed technique makes it possible to assess the integrity of the thin dielectric and at the same time to control the charge effects of its degradation. The method in particular can be used for manufacturing processes to control integrated circuits (ICs) based on MIS structures. In the paper, we propose an advanced algorithm of the Bounded J-Ramp testing of the gate dielectric and receive its approval when monitoring the quality of the gate dielectrics of production-manufactured MIS devices. We found that the maximum value of positive charge obtained when tested by the proposed method was a value close to that obtained when the charge was injected into the dielectric under a constant current with a Bounded J value despite large differences in the rate of degradation of the dielectric. [ABSTRACT FROM AUTHOR]

This study presents the dielectric properties of a barium titanate–gadolinium ferrite composite material, obtained through a solid-state reaction method. The aim of this research was to create a composite material with enhanced dielectric properties compared to each individual component, and to investigate the electrical properties of the composites, using impedance spectroscopy. The structural and morphologic properties were analyzed using X-ray diffraction and scanning electron microscopy, respectively. Impedance spectroscopy measurements were performed over a wide frequency range (100–0.1 GHz) and temperature (45–170 °C) to evaluate the electrical behavior of the material. The dielectric relaxations were analyzed using the Havriliak–Negami function, and the key electrical parameters such as relaxation frequency, dielectric strength, and electrical conductivity were extracted. Several relaxation processes were identified, which depend on the mixture of the initial titanate and ferrite materials, and a correlation between structural, morphologic, and electrical properties was exposed. The sample with the highest dielectric constant was the 25 wt% gadolinium ferrite composite, with ε′ close to 240 and loss tangent values below 0.1, affording it the more appropriate composition for energy storage devices such as lead-free dielectric capacitors. [ABSTRACT FROM AUTHOR]

The present work begins with the investigation of a large number of studies that give the phase diagram of Y–Al–O ternary compounds. Furthermore, the phase compositions of the Y 2 O 3 –Al 2 O 3 system at different temperatures are obtained by high-temperature in situ XRD detection. The constitutive relationships between the lattice properties, grain development, polarizability, internal strain and microwave dielectric properties of the three Y–Al oxides (Y 4 Al 2 O 9 , YAlO 3 , Y 3 Al 5 O 12) are elaborated in detail. As an ideal candidate crystalline material for terahertz wave transmission dielectric devices, yttrium-aluminum-garnet ceramics have a dielectric constant of 11.7 in the real part and a Q × f value of 214,735 GHz at high-frequency band (THz). [ABSTRACT FROM AUTHOR]

GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs) with scandium aluminum nitride Sc0.2Al0.8N/SiNX composite gate dielectric were demonstrated with improved device performance in terms of current density, on-resistance, breakdown voltage, gate leakage, and current collapse. GaN MIS-HEMTs with single-layer Sc0.2Al0.8N or SiNX were also fabricated as reference. Notably, the current collapse was reduced from ∼38.8% in GaN MIS-HEMTs with single-layer SiNX dielectric to ∼4.9% in the device with composite gate dielectric. The insertion of the thin SiNX layer can mitigate the surface damage due to the ScAlN sputtering process and significantly reduce the interface state density. Furthermore, the high valence band offset of Sc0.2Al0.8N/SiNX of 0.78 eV also plays a key role in the suppression of hole injection and gate leakage current. This work shows the effectiveness of the Sc0.2Al0.8N/SiNX composite gate dielectric and can serve as an important reference for future developments of high-performance reliable GaN HEMTs for power and RF electronics. [ABSTRACT FROM AUTHOR]

Plasma discharges under atmospheric pressure are applicable for modifying the electrical properties of dielectric surfaces. The aim of the plasma discharge treatment of such surfaces is to design a procedure so that its characteristic parameters improve the resulting levels of the breakdown electrical strength Eb when tested under pulsed or alternating electrical voltages. In this research, a set of functional experiments performed by using plasma in samples of two types of materials (thermoset, thermoplastic) were processed and evaluated, and the resulting effect of the magnitude of the breakdown electrical voltage, electrical intensity, and electrical conductivity of the surface were compared. A slit plasma chamber, previously described and parameterized, was employed to treat the surface of the dielectric samples. The surface structure was modified via plasma discharge without precursors, and methodologies were developed to evaluate these modifications with respect to the change in the electrical strength parameters of the insulator surface. Subsequently, the surface strength of the affected and unaffected samples was measured and evaluated as a function of exposure time, and the stability of the modification was assessed. The first methodical test showed that plasma discharge without precursors improved the long-term surface electrical strength of the dielectric surface. The test and its parameters were carried out with respect to feasibility in an industrial environment. [ABSTRACT FROM AUTHOR]

This work deals with the assessment of gate dielectric for 4H‐SiC MOSFETs using technology based two‐dimensional numerical computer simulations. Results are studied for variety of gate dielectric candidates with varying thicknesses using well‐known Fowler‐Nordheim tunneling model. Compared to conventional SiO2 as a gate dielectric for 4H‐SiC MOSFETs, high‐k gate dielectric such as HfO2 reduces significantly the amount of electric field in the gate dielectric with equal gate dielectric thickness and hence the overall gate current density. High‐k gate dielectric further reduces the shift in the threshold voltage with varying dielectric thicknesses, thus leading to better process margin and stable device operating behavior. For fixed dielectric thickness, a total shift in the threshold voltage of about 2.5 V has been observed with increasing dielectric constant from SiO2 (k = 3.9) to HfO2 (k = 25). This further results in higher transconductance of the device with the increase of the dielectric constant from SiO2 to HfO2. Furthermore, 4H‐SiC MOSFETs are found to be more sensitive to the shift in the threshold voltage with conventional SiO2 as gate dielectric than high‐k dielectric with the presence of interface state charge density that is typically observed at the interface of dielectric and 4H‐SiC MOS surface. [ABSTRACT FROM AUTHOR]

Moderate dielectric constant, low dielectric loss, and high dielectric tunability around or above Curie temperature are essential characteristics of dielectric tunable devices. Silver niobate (AgNbO 3), known for its antiferroelectric (AFE) and weak ferroelectric (FE) nature, offers a natural "composite" system combining AFE and FE attributes, making it an attractive candidate for tunable device materials. Microstructural modification through chemical methods can enhance its dielectric tunability. To this end, we propose and prepare a doped AgNbO 3 ceramic system, denoted as (1- x) AgNbO 3 - x LiTaO 3 (ANLT100 x , x ≤ 3.8 mol%). Structural analysis reveals that all samples maintain an average AFE-like polar structure. The introduction of dopants disrupts the ordered AFE-like structure, altering the proportion of AFE and FE states. This disruption leads to a notably improved relaxor dielectric response and an FE transition around room temperature. Consequently, we achieve a ceramic material (x = 3.8 %) with a moderate dielectric constant (ε r = 520) and low dielectric loss (tanδ = 0.008), accompanied by a hysteresis-free dielectric tunability (n r = 37.2 %) under an applied bias electric field of 40 kV cm−1, which is four times larger than that in AgNbO 3 (n r = 8 %) ceramic. These findings open new possibilities for developing dielectric tunable materials in device design. [ABSTRACT FROM AUTHOR]

The in situ metalorganic chemical vapor deposition (MOCVD) growth of Al2O3 dielectrics on β-Ga2O3 and β-(AlxGa1−x)2O3 films is investigated as a function of crystal orientations and Al compositions of β-(AlxGa1−x)2O3 films. The interface and film qualities of Al2O3 dielectrics are evaluated by high-resolution x-ray diffraction and scanning transmission electron microscopy imaging, which indicate the growth of high-quality amorphous Al2O3 dielectrics with abrupt interfaces on (010), (100), and ( 2 ¯ 01) oriented β-(AlxGa1−x)2O3 films. The surface stoichiometries of Al2O3 deposited on all orientations of β-(AlxGa1−x)2O3 are found to be well maintained with a bandgap energy of 6.91 eV as evaluated by high-resolution x-ray photoelectron spectroscopy, which is consistent with the atomic layer deposited (ALD) Al2O3 dielectrics. The evolution of band offsets at both in situ MOCVD and ex situ ALD deposited Al2O3/β-(AlxGa1−x)2O3 is determined as a function of Al composition, indicating the influence of the deposition method, orientation, and Al composition of β-(AlxGa1−x)2O3 films on resulting band alignments. Type II band alignments are determined at the MOCVD grown Al2O3/β-(AlxGa1−x)2O3 interfaces for the (010) and (100) orientations, whereas type I band alignments with relatively low conduction band offsets are observed along the ( 2 ¯ 01) orientation. The results from this study on MOCVD growth and band offsets of amorphous Al2O3 deposited on differently oriented β-Ga2O3 and β-(AlxGa1−x)2O3 films will potentially contribute to the design and fabrication of future high-performance β-Ga2O3 and β-(AlxGa1−x)2O3 based transistors using MOCVD in situ deposited Al2O3 as a gate dielectric. [ABSTRACT FROM AUTHOR]

We theoretically describe and experimentally demonstrate a graphene-integrated metasurface structure that enables electrically-tunable directional control of thermal emission. This device consists of a dielectric spacer that acts as a Fabry-Perot resonator supporting long-range delocalized modes bounded on one side by an electrostatically tunable metal-graphene metasurface. By varying the Fermi level of the graphene, the accumulated phase of the Fabry-Perot mode is shifted, which changes the direction of absorption and emission at a fixed frequency. We directly measure the frequency- and angle-dependent emissivity of the thermal emission from a fabricated device heated to 250 °C. Our results show that electrostatic control allows the thermal emission at 6.61 μm to be continuously steered over 16°, with a peak emissivity maintained above 0.9. We analyze the dynamic behavior of the thermal emission steerer theoretically using a Fano interference model, and use the model to design optimized thermal steerer structures. Dynamic angular tuning of thermal emission is a problem in the field of thermal metasurfaces. Here, the authors make a thermal emission device using electrostatic gates, opening an avenue for radiative heat management and mid-infrared communication. [ABSTRACT FROM AUTHOR]

High- Q and temperature-stable ceramics are indispensable in microwave engineering. However, medium-permittivity (ε r ∼ 60, named as K60) microwave dielectric ceramics that meet the above demands are yet to be synthesized. High- Q Ba 4 Sm 9.33 Ti 16.5 Al 2 O 54 (BSTA) and Ca 0.6 Sm 0.27 Ti 0.8 Al 0.27 O 3 (CSTA) ceramics have large resonant frequency temperature coefficients (τ f) with opposite signs. The composites of the two are expected to have good dielectric properties, but there will be obvious diffusion when they are compounded with each other by sintering after directly mixing the raw powder, which would lead to severe deterioration in dielectric properties. In this work, the undesired diffusion can be effectively avoided by stacking two or three ceramic layers together, which are achieved by two methods named adhesive bonding and spark-plasma-sintering (SPS) cofiring. The finite element method (FEM) analysis with COMSOL Multiphysics proposed in this work can precisely predict the microwave dielectric properties of layered ceramics, helping to determine the ratio of different layers to reach near-zero τ f. The adhesive-bonded layered ceramics exhibit excellent dielectric properties: ε r = 62.2, Q × f = 21,400 GHz, and τ f = –0.7 ppm/°C. The SPS-cofired layered ceramics can be fabricated in one time, partially solving the problem of sintering mismatch between different layers, together with superior properties of ε r = 59.8, Q × f = 19,780 GHz, and τ f = –0.6 ppm/°C. These layered ceramics could fill the gap of high- Q and temperature-stable K60 microwave dielectric ceramics. The layer-stacking process and related FEM simulations can be used to design more high- Q and temperature-stable microwave dielectric ceramics and devices. • High- Q , temperature stable K60 ceramics are obtained (Q × f ∼ 20,000 GHz). • The diffraction in the directly-mixing process is thoroughly examined. • FEM simulation can precisely predict the properties of layered ceramics. • SPS-cofiring can partially solve the problem of sintering mismatch. [ABSTRACT FROM AUTHOR]

In this work, a Symmetrical Dual Gate Tunnel Field Effect Transistor (SDGTFET) is proposed with gate dielectric materials in 10nm technology. The electrical performance parameters of this proposed device are investigated using technology computer aided design (TCAD) simulator. The new SDGTFET employing with high-k dielectric material such as hafnium oxide (HfO2) and interfacial layer (IL). The 2nm HfO2 with 30 dielectric constant is used between the interfacial layer and the metal gate on both sides of the device. The variation of the drain current with the varying of gate length, effective gate materials and effective oxide layer thickness of the device is evaluated in this work. By optimizing the proposed device with gate dielectric material the on current gets ~4.2 times enhanced and the averaged subthreshold swing (SSavg) becomes reduced from 90.2 mV/dec to 53.8 mV/dec. Therefore, the SDGTFET structure has better performance than single material and double material TFET and shows a lower ambipolar current and a better on current to off current ratio. [ABSTRACT FROM AUTHOR]

Vertical stacking of different two-dimensional (2D) materials into van der Waals heterostructures exploits the properties of individual materials as well as their interlayer coupling, thereby exhibiting unique electrical and optical properties. Here, we study and investigate a system consisting entirely of different 2D materials for the implementation of electronic devices that are based on quantum mechanical band-to-band tunneling transport such as tunnel diodes and tunnel field-effect transistors. We fabricated and characterized van der Waals heterojunctions based on semiconducting layers of WSe2 and MoS2 by employing different gate configurations to analyze the transport properties of the junction. We found that the device dielectric environment is crucial for achieving tunneling transport across the heterojunction by replacing thick oxide dielectrics with thin layers of hexagonal-boronnitride. With the help of additional top gates implemented in different regions of our heterojunction device, it was seen that the tunneling properties as well as the Schottky barriers at the contact interfaces could be tuned efficiently by using layers of graphene as an intermediate contact material. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of the design of a high-performance meta-material loaded square patch antenna arrays specifically tailored for X-band applications. To enhance the gain and front to back ratio (FTBR), a novel 1x3 series-fed linear array configuration that integrates solitary series-fed elements with metamaterial-based square patches at X-band frequencies is introduced. Later, parallel-fed 1x2 and 1x4 antenna arrays are designed by considering the series-fed antenna array as a single element for further enhancement of gain and FTBR. The single element 1x3 series fed array is fabricated with dimensions of λx3.5λx0.028λ, whereas the respective 1x2 and 1x4 parallel fed antenna arrays has the dimensions of 2.86λx3.8λx0.028λ and 2.86λx4.3λx0.028λ, respectively. The Taconic substrate is chosen as the dielectric material, exhibiting a dielectric constant of 2.2 and a loss tangent of 0.0025. The empirical data presented substantiates the superior performance of the 1x4 parallel fed configuration. This is evident through the remarkable reflection coefficient of -25dB, the wide bandwidth spanning 47MHz, the substantial gain of 17.8dBi, and the FTBR of 30.7. The metrics serve to highlight the array's capacity in guaranteeing a superior level of signal fidelity, encompassing a wide frequency spectrum, amplifying incoming signals, and directing transmissions towards specific orientations. These metrics unequivocally validate its potential for advanced X-band applications. [ABSTRACT FROM AUTHOR]

Donor doping can increase the dielectric constant of a material by several orders of magnitude due to induced space charge causing interfacial polarization. Giant dielectric properties and interface polarization are also both expected to greatly enhance the flexoelectric behavior of a material. In this work, a typical flexoelectric ceramic material, BaTiO3, was selected and donor doped using elemental Nb. Compared with the nominal BaTiO3 ceramic, the dielectric constant and flexoelectric coefficient of the Nb-doped BaTiO3 ceramics were significantly improved. The transverse flexoelectric coefficient of 0.3 mol. % Nb-BaTiO3 was found to increase to nearly 40 times the nominal value, reaching 387 μC/m. The results indicate that the giant dielectric response, and therefore the giant flexoelectric response, is the result of the combined effects of internal barrier-layer capacitance and surface barrier-layer capacitance. This study not only deepens the understanding of the semiconductor macro-dielectric effect and the flexoelectric mechanism caused by doping, but it also provides a feasible strategy for the design of giant dielectric/flexoelectric response materials and related devices with high dielectric constants and flexoelectric coefficients. [ABSTRACT FROM AUTHOR]

A polycrystalline ceramic oxide, BaFe2MnO6 was produced through a regular solid-state route. The phase creation in the synthesized substance was investigated through X-ray diffraction (XRD) technique. The present material has found with made up of a single phase orthorhombic structure. The electrical properties of the compound were recorded through an LCR meter for a broader range of frequencies and temperatures. This perovskite oxide material possesses a large relative permittivity (ɛr = 1139) and low dielectric loss (tanδ = 0.421) at the ambient atmospheric condition, while the curie temperature arise beyond 450 °C. The resultant dielectric properties of this material assure its promising candidature for feasible applications in smart electronic devices such as dielectric material in ceramic capacitors. [ABSTRACT FROM AUTHOR]

The green synthetic approaches have advantages over conventional methods, which employ environmentally harmful chemical agents. The present work focuses on the green synthesis of polyvinyl alcohol (PVA)/chitosan (CS) blend reinforced with 5, 10, 15 and 20 wt% of Asparagus racemosus (AR) as a bio-filler. The FTIR study reveals the main distinctive absorption peaks of PVA and CS, whose positions slightly vary by the addition of AR. The minimum optical bandgap energy was observed for a 15 wt% bio-filler-loaded blend composite. The decrease in intensity and shift in X-ray diffraction peak compared to pure blend confirmed the existence of AR filler in the blend matrix. The scanning electron microscopic pictures revealed obvious changes in the morphology of the blend with the reinforcement of AR. The TG analysis demonstrates that the inclusion of AR slightly increased the thermal stability of the biopolymer blend. The glass transition and melting temperature of the PVA/CS blend were significantly increased with the addition of AR. The AC electrical conductance improved significantly with temperature and the addition of AR up to 15 wt% loading. The activation energy of AC conductivity decreases as the temperature rises. The hardness and tensile strength of the PVA/CS/AR composites were significantly enhanced by the reinforcement of AR to the biopolymer blend matrix. The enhancement in the thermal properties, tensile strength and electrical characteristics make this biopolymer blend composite material suitable for a wide range of applications, including integrated thin film capacitors, flexible dielectric devices, and many energy storage devices. [ABSTRACT FROM AUTHOR]

This paper examines a charge plasma‐based hetero‐structure full gate vertical tunnel field effect transistor (CP‐FG‐VTFET) as a dielectrically modulated biosensor. It is also compared with a charge plasma‐based short gate vertical TFET (CP‐SG‐VTFET) biosensor and a charge plasma‐based asymmetrical vertical TFET (CP‐AS‐VTFET) biosensor with identical dimensions. We examine the basic physics of these biosensors and compare their ability to recognize charged and neutral molecules. It has been noted that these designs, which use GaSb as the n‐type TFET source material, are suitable for supply voltages lower than 1.2 V. The short gate device has a lower miller capacitance and a higher drive current because it has a narrow bandgap source material. Additionally, the left and right gate alignment of asymmetrical gate architectures has a considerable impact on the sensitivity of the device. Therefore, a simulation is conducted to assess the effects of gate misalignment on biosensor surface potential and drain current sensitivity. In addition, various figures of merits (FOMs) are computed for the device utilizing the dielectric constant range of 1–12, including linearity, sensitivity, and evaluation of noise characteristics. The widely available Silvaco TCAD was employed to simulate the proposed VTFET biosensors. A comprehensive evaluation of the FOM values showed that the CP‐FG‐VTFET is a promising device in terms of linearity and sensitivity. [ABSTRACT FROM AUTHOR]