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Silicon–germanium heterostructures are a promising quantum circuit platform, but crucial aspects, such as the long-term charge dynamics and cooldown-to-cooldown variations, are still widely unexplored quantitatively. In this Letter, we present the results of an extensive bias cooling study performed on gated silicon–germanium quantum dots with an Al2O3 dielectric. Over 80 cooldowns were performed in the course of our investigations. The performance of the devices is assessed by low-frequency charge noise measurements in the band of 200 μHz to 10 mHz. We measure the total noise power as a function of the applied voltage during cooldown in four different devices and find a minimum in noise at 0.7 V bias cooling voltage for all observed samples. We manage to decrease the total noise power median by a factor of 6 and compute a reduced tunneling current density using Schrödinger–Poisson simulations. Furthermore, we show the variation in noise from the same device in the course of eleven different cooldowns performed under the nominally same conditions. [ABSTRACT FROM AUTHOR]

Thermochromic perovskites, renowned for their tunable bandgap, high absorption coefficient, and reversible color changes, emerge as promising candidates for applications in smart windows. These advancements not only have the potential to enhance occupant comfort but also contribute significantly to reducing energy consumption in buildings. Here, we present a two‐dimensional lead‐free organic‐inorganic hybrid perovskite [Cyclobutylammonium]2CuCl4 which shows phase transitions from C2/c to P21/c to P21/c space group at 319.5 K and 348.8 K, respectively. Accompanying these transitions is a fascinating, reversible thermochromic behavior that is dependent on the phase structure. This behavior manifests as a vibrant sequence transitioning from yellow to brown and finally to a slightly dark brown. Most importantly, the demonstrated ability to switch stably between high and low dielectric states indicates the enormous potential of this material as a dielectric switch. This non‐toxic thermoresponsive perovskite, characterized by its appropriate transition temperatures, reversible phase structure‐dependent thermochromism, and stable dielectric switching behavior, is expected to generate significant interest within the fields of thermoresponsive and dielectric switching materials. The integration of these features not only positions this perovskite as a noteworthy subject of scientific inquiry but also opens avenues for practical applications in diverse fields. [ABSTRACT FROM AUTHOR]

The investigation of dual-mode synaptic plasticity was conducted in thin-film transistors (TFTs) featuring an HfSe2 channel, coupled with an oxygen-deficient (OD)-HfO2 layer structure. In these transistors, the application of negative gate pulses resulted in a notable increase in the post-synaptic current, while positive pulses led to a decrease. This distinctive response can be attributed to the dynamic interplay of charge interactions, significantly influenced by the ferroelectric characteristics of the OD-HfO2 layer. The findings from this study highlight the capability of this particular TFT configuration in closely mirroring the intricate functionalities of biological neurons, paving the way for advancements in bio-inspired computing technologies. [ABSTRACT FROM AUTHOR]

A series of new liquid crystal compounds with negative dielectric anisotropy was synthesised by regulating the orientation of the substituents on the benzoxazole ring, namely, 5–4-(2-(4-(alkoxy)phenyl)-2,3-difluorophenyl)benzo[d]oxazole derivatives (nPP(2,3)FO). These compounds mainly display enantiotropic nematic mesophases in the ranges of 8.62–16.09°C (heating process) and 23.98–30.32°C (cooling process), moderate birefringence (Δn) ranging from 0.25–0.32 (DFT theoretical calculation) and 0.22–0.28 (experimental measurement), as well as negative dielectric anisotropy (Δɛ) ranging from −2.77 to −2.94. These characterises are ascribed to the larger perpendicular dipole moments and orientation angles of benzoxazole. This work provides new ideas for the rational design of negative dielectric anisotropy liquid crystals. [ABSTRACT FROM AUTHOR]

Odor and discoloration in water-based cutting fluids are caused by the growth of microorganisms and putrefying bacteria. This significantly reduces cutting performance, prevents rust, and deteriorates the working environment. To overcome these drawbacks, we developed a compact air-cooled coaxial dielectric barrier discharge (DBD) with a bubbler. Bacteria and microorganisms living in waste cutting fluids were sterilized by the high concentration of ozone produced under the optimized conditions of the compact air-cooled coaxial DBD. Moreover, it was confirmed that 99.99% of bacteria and microorganisms were completely removed. Ozone was found to not affect property changes such as the composition, concentration, and pH of the water-based cutting fluids. The chromaticity and complex odor of waste cutting liquids were thus found to have been improved by the effects of microorganism and bacterial sterilization. We conclude that the proposed a compact air-cooled coaxial DBD with a bubbler is an efficient method for sterilizing water-based cutting fluids. [ABSTRACT FROM AUTHOR]

Quantum computing is expected to break the computing power bottleneck with the help of quantum superposition and quantum entanglement. In order to fabricate fault-tolerant quantum computers for encoding quantum information, it is important to improve the cryogenic mobility of silicon-based metal oxide semiconductor field effect transistors (MOSFETs) with a thin gate dielectric layer as much as possible. Based on a thin SiO2/HfO2 stacked dielectric, we investigate the effect of post-deposition annealing (PDA) temperature on the MOSFET cryogenic transport properties. The results show that silicon atoms will diffuse into the HfO2 to form silicates during PDA, leading to the HfO2 dielectric constant decrease. As the PDA temperature increases, the proportion of monoclinic hafnium oxide decreases and the tetragonal phase increases gradually. The oxygen vacancy content increases gradually, resulting in fixed charge density increases and the mobility decreases. The contribution of the forming gas annealing (FGA) to the mobility enhancement is clarified and the HfO2 recrystallization process is revealed from the perspective of long-time annealing. Finally, the mobility peak of silicon MOSFETs with thin SiO2/HfO2 dielectrics is enhanced to 1387 cm2(V·s)−1 at 1.6 K, which provides a technical pathway for the development of silicon-based quantum computation. [ABSTRACT FROM AUTHOR]

In general, inorganic non‐metallic materials exhibit brittleness, and achieving plasticity in wide‐gap semiconductors or dielectrics poses an even greater challenge. Historically, silver halides have been suggested to be ductile; however, their deformability under different load modes has not been well demonstrated, and the underlying mechanisms are not fully understood. In this study, the authors demonstrate the excellent plasticity of AgCl and AgBr polycrystals at room temperature under tension, bending, compression, and roller pressing. In particular, the rolling reduction rate of AgCl/AgBr exceeds 97%, corresponding to the plastic extensibility from 3600% to 4200%. The metal‐like plasticity and multiple slip systems are attributed to the ionic features, specifically the Coulombic nature of the Ag‐Cl/Br interactions, and the appreciable polarization of the anions. Such less localized diffuse bonding can be readily switched upon atomic gliding, thus ensuring slip without cleavage. This study contributes to the advancement of the understanding and development of wide‐gap plastically deformable inorganic materials for applications in flexible, shape‐conformable high‐power electronics and dielectrics. [ABSTRACT FROM AUTHOR]

A stacked dielectric magnetoelectric antenna with embedded ceramics (SDMEA-EC) is proposed. The antenna consists of a stacked dielectric resonator antenna with embedded ceramics and a leaf-shaped electric dipole (LSE-Dipole). To improve the performance of the magnetoelectric dipole antenna, a novel verification method is proposed by analyzing equivalent magnetic currents to meet the Huygens element principle. The stacked structure with embedded ceramics is helpful for expanding the impedance bandwidth. The electric dipole not only participates in the radiation but also is a part of the feed network, which simplifies the overall structure. The prototype of the proposed stacked dielectric resonator magnetoelectric antenna achieves an impedance bandwidth of 20.2 % in the high frequency band (5.35 GHz–6.55 GHz) and 13.4 % in the low frequency band (4.54 GHz–5.19 GHz), an over 6.7 dBi gain, and a cross-polarization discrimination (XPD) of greater than 30 dB. [ABSTRACT FROM AUTHOR]

Ceramic–polymer nanocomposites are widely used in various applications, such as medicine, aerospace, optoelectronic devices, and energy storage devices, owing to their impressive mechanical, thermal, optical, and electrical properties. Due to an excellent capability to combine a high dielectric constant of ceramics and a high breakdown strength of polymers, the preparation of ceramic–polymer dielectric nanocomposites is a promising and widely accepted approach to develop capacitors with high energy density, low dielectric loss, and good flexibility. In this paper, poly(vinylidene fluoride) (PVDF) was used as the polymer matrix. Silane coupling agent, KH550, with different contents (3 wt.%, 6 wt.%, 9 wt.%, 12 wt.%, 15 wt.%, 18 wt.%) was added to modify the surface of BaTiO3 ceramic particles to improve the compatibility between BaTiO3 and PVDF using a film processing technique of spin coating. By comparison between the unmodified and modified ceramic–polymer nanocomposites by the addition of the silane coupling agent, KH550, the dielectric constant, breakdown strength, and energy storage density were studied. It was found that the addition of the silane coupling agent did not change the crystal structure of BaTiO3. Moreover, the changing trends of dielectric constant and dielectric loss of the BaTiO3/PVDF/KH550 and the unmodified nanocomposites in sweeping frequency were studied. In addition, KH550 can improve the compatibility of the BaTiO3 nanoparticles and the PVDF matrix, and also increase the breakdown strength (by 55.6%), and energy storage density (by 56%), of BaTiO3/PVDF nanocomposites compared with unmodified ones. [ABSTRACT FROM AUTHOR]

2D MoTe2 is regarded as a favorable candidate for semiconductor nanoelectronics integration. Chemical‐vapor‐deposition‐grown MoTe2 usually presents p‐type characteristics. In order to realize basic electronic units like complementary metal‐oxide‐semiconductor (CMOS) inverter, controllable fabrication of p‐ and n‐type transistors at large scale is of vital importance. Here, large‐scale MoTe2 n‐channel field‐effect transistor (n‐FET) arrays are successfully fabricated with seamless coplanar metallic 1T′‐WTe2 contacts to reduce contact resistance. High‐k HfO2 serves as a gate dielectric and its atomic‐layer‐deposition (ALD) process causes an n‐doping effect on the 2H‐MoTe2 channel. The FETs perform typical n‐type characteristics with average electron density and on/off ratio of ≈1.7 × 1013 cm−2 and 2.1 × 104, respectively. Furthermore, large‐scale homogeneous CMOS inverter arrays are fabricated, showing clear logic swing with low power consumption (≈0.4 nW) and high device yield (≈92%). Notably, their voltage transfer characteristics exhibit small hysteresis, and they work well after being kept in air for 16 months, indicating high device stability. The statistical results show that both the n‐FETs and CMOS inverters have high uniformity and reliability in performance. Significantly, this fabrication method is free from transfer processes and compatible with traditional silicon technology. This work paves the way for the application of few‐layer MoTe2 in semiconductor nanoelectronics integration. [ABSTRACT FROM AUTHOR]

Attaining compact energy storage under extreme temperature conditions is of paramount importance in the development of advanced dielectric materials. The polymer composite approach has proved effective towards this goal, and addressing the correlation between filler distribution and electrical properties is foremost in designing composite dielectrics, especially in multifiller systems. Here, the design of a bi‐gradient polymer composite dielectric using an integrated framework based on the phase field model is reported. This framework can predict the charge‐inhibiting behavior of composite dielectrics, which is a key factor impacting the high‐temperature capacitive performance but unfortunately is ignored in conventional phase field models. It is found that due to the traps provided by the functional organic fillers, more carriers are trapped near the electrodes and weaken the electric field, thus significantly suppressing the breakdown initialization process. An interpenetrating gradient structure is designed rationally and synthesized experimentally, which exhibits concurrent high energy density (5.51 J cm−3) and high charge‐discharge efficiency (90%) up to 200 °C. This work provides a strategy to predict the high‐temperature energy storage performance of polymer composites containing charge‐inhibiting components and helps broaden the scope of data‐driven materials design based on phase‐field modeling. [ABSTRACT FROM AUTHOR]

Hydrogen-terminated diamond surfaces, emerging as a promising two-dimensional (2D) electron platform with great thermal and electronic properties, hold great potential for the next-generation high power and high frequency field effect transistor (FET). However, ideal gate dielectrics with high crystallinity and defect-free surfaces are still largely elusive. In this work, using the contamination-free pickup transfer method, hexagonal boron nitride (h-BN) flakes were fabricated on top of the hydrogen-terminated diamond surface to serve as a gate material and the passivation layer. The morphological and optical characterizations revealed the formation of homogeneous and intimate interface between h-BN and diamond. Benefiting from the h-BN gate dielectric layer, the maximum drain current density, subthreshold swing, and on/off ratio of diamond FET are measured to be −210.3 mA mm−1, 161 mV/dec, and 106, respectively. Especially, the transport measurement shows an almost constant Hall mobility of around 260 cm2 V−1 s−1 in the hole density range of 2 − 6 × 1012 cm−2, suggesting the excellent gate controllability of h-BN. Our results indicate that h-BN could form high-quality interface with hydrogen-terminated diamond, paving the way for the development of diamond-based electronic applications. [ABSTRACT FROM AUTHOR]

There are still challenges in the precise control of microwave energy for the industrial production, one of which is the effective inhibition of microwave hotspots or thermal runaway during microwave radiation, which has become a long-standing problem for improving heating uniformity and further expanding applications. Nevertheless, the evolution process and the underlying mechanism of microwave hotspots in high-dielectric dimers within different applied dielectrics are not fully understood due to the difficulty of internal temperature measurement. In this Letter, an optical indirect observation method has been proposed to characterize the hotspots distribution inside the applied dielectric. The grapes with high relative permittivity have been selected, which are easy to cut and absorb microwave, to conduct an in situ investigation of microwave hotspots evolution for dimers in a domestic microwave oven using the thermal and optical imaging. The results show that with the increase in the relative permittivity of applied dielectric, the starting of microwave plasma is prevented, and the focused hotspots disappear. Most significantly, the heating uniformity of dimers in water is improved by about ten times compared to that in air. The reduction of the calculated focused energy density near the contact point verifies the weakening effect of applied dielectric on the microwave cooperative resonance of dimers and explains the experimental phenomenon. These findings can be directly applied to inhibit the formation of focused hotspots for dimers or even multi-particle systems during the microwave processing and also provide a better understanding for cooperative interaction of Mie resonances. [ABSTRACT FROM AUTHOR]

In this article, the dielectric properties of polypropylene (PP) films are investigated under 0–12-T magnetic field. The modification method based on aromatic compound blending is proposed to improve the performance of PP in the strong electromagnetic environment. Under the 12-T magnetic field, the dielectric constant declines from 2.34 to 2.27 at 1 kHz, and the dielectric loss grows up from 0.40% to 0.64% at 1 kHz. The leakage conductivity increases from $0.56\times 10^{-{12}}$ to 1.85 $\times \,\,10^{-{12}}$ S/m. The breakdown strength drops from 546.1 kV/mm under 0 T to 454.2 kV/mm under 12 T. The energy density of PP decreases from 3.09 to 2.07 J/cm3 due to the magnetic field. After blending with 0.05 wt% aromatic compounds, the dielectric properties of PP films got enhanced. The energy storage density of the modified films reaches 3.63 (under 0 T) and 2.72 (under 12 T) J/cm3 with enhanced voltage resistance and enlarged dielectric constant. This article is of significance to the application of PP capacitors under strong electromagnetic environment. [ABSTRACT FROM AUTHOR]

SrHfO3 is a potential dielectric material for metal-oxide-semiconductor devices. The SrHfO3/ GaAs interface has attracted attention because of its unique properties. In this paper, the interface properties of (001) SrHfO3/GaAs are investigated by first-principles calculations based on density functional theory. First, the adsorption behavior of Sr, Hf, and O atoms on the GaAs surface is investigated. An O atom has a lower adsorption energy on a Ga surface than on an As surface. Then, some possible (001) SrHfO3/GaAs configurations are considered to analyze the interface spacing, stability, band offsets, and charge transfer. The SrO/Ga(1) and HfO2/Ga(2) configurations are lower in binding energy than other interface configurations, indicating that they are more stable. Finally, we study the electronic properties of the SrO/Ga(1) and HfO2/Ga(2) configurations. The electronic density of states suggests that these systems exhibit metallic behavior. The band offset and charge transfer are related to the interface spacing. The valence band offset and charge transfer decrease with increasing interface spacing. [ABSTRACT FROM AUTHOR]

Current rectification behavior has been proved to be essential in modern electronics. Here, a pseudo-diode is proposed based on protonic/electronic hybrid indium-gallium-zinc oxide electric- double-layer (EDL) transistor. The oxide EDL transistors are fabricated by using phosphorous silicate glass (PSG) based proton conducting electrolyte as gate dielectric. A diode operation mode is established on the transistor, originating from field configurable proton fluxes within the PSG electrolyte. Current rectification ratios have been modulated to values ranged between ~4 and ~50 000 with gate electrode biased at voltages ranged between -0.7 V and 0.1 V. Interestingly, the proposed pseudo-diode also exhibits field reconfigurable threshold voltages. When the gate is biased at -0.5 V and 0.3 V, threshold voltages are set to 1.3 V and -0.55 V, respectively. The proposed pseudo-diode may find potential applications in brain-inspired platforms and low-power portable systems. [ABSTRACT FROM AUTHOR]

The energy density of dielectrics could be evaluated both via low-frequency P–E loop (quasi-static recoverable energy density, Wre) and fast discharge current (dynamic discharge energy density, Wdis). The value of Wdis represents the useful energy, which can be converted to electrical energy while most work about high-energy-density dielectrics is focused on enhancing Wre. In this work, we investigated the relationship between Wdis and Wre in (Pb1 − 3x/2Lax)[(Zr0.45Sn0.55)0.99Ti0.01]O3 antiferroelectrics. Tuning the phase transition properties could improve the fast discharge capability by reducing the difference between Wdis and Wre and accelerating the energy release rate. At 300 kV/cm, the composition with x = 0 has the highest Wre of 6.7 J/cm3 but a lower Wdis of only 4 J/cm3 and longer discharge time duration, indicating a "high-energy-density" (highest Wre) quasi-static performance but "low-energy-density" (lower Wdis) and slow discharge performance during fast discharge. A highest Wdis of 5.9 J/cm3 and power density were achieved in composition with x = 0.2 though with lower Wre. The various fast energy release performance was explained by their different domain mobility and phase switching behavior. Thus, purely pursing high Wre is with limitation and suppressing the difference between Wdis and Wre is with great significance. This work will give an approach for the development of energy storage dielectrics by connecting their fast discharge performance with polarization mechanism. [ABSTRACT FROM AUTHOR]

In this article, parylene doping method is proposed for enhancing the breakdown strength and reducing leakage conductivity of polypropylene (PP) films for power capacitors. The results indicate that 0.01 wt% parylene bulk doping PP membranes can reduce the leakage conductivity to 15%–27% at different temperatures. The breakdown strength is enhanced by 50% at 85 °C. The 0.05 wt% multilayer constructed doping membranes can further improve the dielectric properties, whose conductivity declines to 2% at 85 °C, with the same breakdown strength. Among all kinds of parylene additives, those with fluorine side groups exhibit the best electrical resistance, the conductivity of which is reduced to less than 1%. The multilayer constructed PP film presents advanced insulation performance with the charge injection being inhibited. The results provide a reference for structure optimization for film capacitors. [ABSTRACT FROM AUTHOR]

An amorphous Al2O3 (a-Al2O3)/MoS2 interface has attracted much attention because of its unique properties. In this study, the interface behaviors under non-strain and biaxial strain are investigated by first principles calculations based on the density functional theory. First of all, the generation process of the a-Al2O3 sample is described by molecular dynamics. The calculated bandgap of a-Al2O3 is 3.66 eV for generalized gradient approximation-Perdew, Burke, and Ernzerhof and 5.26 eV for Heyd-Scuseria-Ernzerhof functional. Then, we give a detailed description of the band alignment for the a-Al2O3/MoS2 interface. The valence band offset and conduction band offset change with the number of MoS2 layers. It is noted that the valence band maximum (VBM) of MoS2 moves upward as the number of MoS2 layers is increased. The leakage current for metal/a-Al2O3/MoS2 MOS is also illustrated. At last, the band structure of monolayer MoS2 under biaxial strain ranging from -6% to 6% is discussed, and the impact of the biaxial strain on the band offset is investigated. The VBM of monolayer MoS2 moves downward as the strain changes from compressive to tensile. [ABSTRACT FROM AUTHOR]

In this paper, a novel deashing method is proposed to prepare polypropylene (PP) materials with different ash contents (60–500 ppm). Effects of the ash on dielectric and energy storage characteristics of PP in polymer film capacitors are studied. The experimental results reveal that a low content of ash will help to improve the dielectric properties. Compared to the sample with 500 ppm of ash content, the PP film with 60 ppm ash possesses a higher breakdown strength (587.1 kV/mm), a lower DC conductivity (1.12 ×10−14 S/m) and dielectric loss factor (3 ×10−4). In addition, the energy storage property also shows a remarkabe improvement, the discharge energy density can be up to 3.22 J/cm3 and the discharge efficiency remains at a high level. After the purification, the decline of the ash content in PP prevents the local electric field distortion and enhances the breakdown strength, which is beneficial for the improvement of the discharge energy density. Meanwhile, the reduction in the number of carriers ionized by the ash weakens the transport behavior and reduces the conductivity. It is concluded that the PP with high purity shows a great potential in polymer film capacitors. [ABSTRACT FROM AUTHOR]

New benzoxazole-terminated mesogenic compounds containing tolane moiety with high birefringence and large dielectric anisotropy, namely, 2-[4-[2-[4-alkoxyphenyl]ethynyl]-2,6-difluoro-phenyl]-benzoxazole derivatives (nPEDFPBx), were synthesised and investigated. Among them, the ones bearing methyl and nitro substituents at 5-position of benzoxazole moiety exhibit stable mesophase ranges of 30–71°C and 55–81°C during heating and cooling processes, respectively, while the non-substituted compounds exhibit no mesophase except the ones with long terminal alkoxy chain (n = 10, 12). Birefringence of nPEDFPBx is obtained from DFT theoretical calculation (0.446–0.583) and experimental measurement (0.395–0.499), respectively, where high birefringence is ascribed to their large π-conjugated molecule composed of benzene ring, acetylene linkage and benzoxazole moiety. Meanwhile, it is found that nPEDFPBx displays large dielectric anisotropy because of their high dipole moment. As an example, the compound 5PEDFPBM is doped into the liquid crystalline mixture as an additive, the properties of the resulting mixture, such as birefringence, dielectric anisotropy, clearing point and response time, are improved obviously, indicating high potential application for liquid crystalline mixture. [ABSTRACT FROM AUTHOR]

In this article, the hydrogen-terminated diamond metal-oxide-semiconductor field effect transistors (MOSFETs) which can operate at high frequency of 10 GHz are demonstrated. The devices were fabricated with a 50 nm Al2O3 gate insulator and a 350 nm Si3N4 passivation layer, which is compatible with the process of monolithic microwave-integrated circuits (MMICs). The device with gate length of 0.35 $\mu \text{m}$ shows a high drain current density of −561 mA/mm. The RF small signal characteristics and power output performances at 10 GHz for the devices with different gate widths have been investigated. With the gate width increased from 100 to 200 $\mu \text{m}$ , the extrinsic maximum frequency of oscillation ${f} _{\text {max}}$ is slightly decreased from 23 to 21 GHz, whereas the output power density at 10 GHz is improved from 1.05 to 1.26 W/mm, with associated power added efficiency increased from less than 5% to 20.77%. Comparing with the devices fabricated by the self-aligned gate process, the power output performance is significantly improved, indicating it is a promising method to fabricate high power and high frequency diamond MOSFETs by using the thick Si3N4 passivation technique. [ABSTRACT FROM AUTHOR]

The multitrace domain decomposition surface integral equation (MT-DD-SIE) originally developed to analyze electromagnetic scattering from dielectric composite objects is extended to efficiently account for perfect electrically conducting (PEC) bodies. This is achieved by adopting Robin transmission conditions (RTCs) to PEC surfaces. These PEC-RTCs, which are the only governing equations for a PEC body, are used to “couple” it to the dielectric bodies. Upon discretization, PEC-RTCs produce a well-conditioned matrix block and, therefore, does not negatively affect the convergence of the iterative solution of the MT-DD-SIE matrix equation. The resulting method is significantly faster and has a smaller memory footprint than the traditional globally coupled contact-region-modeling method that uses the coupled electric field and Poggio–Miller–Chang–Harrington–Wu–Tsai SIEs in analyzing electromagnetic scattering from composite PEC/dielectric objects. This is demonstrated by numerical examples involving electrically large scatterers. [ABSTRACT FROM AUTHOR]

A high‐precision differential microwave dielectric sensor system based on a pair of CSRR‐SIW resonators is introduced. The proposed method consists of four parts: the frequency‐sweeping signal source, the balanced sensor based on CSRR‐SIW, the RMS power detector, and the data acquisition system. Without a vector network analyzer (VNA) and other instruments, the electromagnetic properties of materials can be measured conveniently with the proposed method. In this work, two CSRR resonators inside SIW cavities are used as the balanced RF sensing components, one for measurement and the other for reference. In virtue of the electric field concentration effect of the CSRR and the high Q factor of SIW cavity, the proposed sensor achieves high sensitivity to material under test (MUT), with high isolation between the balanced resonators and strong capability of suppressing the electromagnetic interferences from the external environment. The resonating frequency of the balanced microwave resonator under no‐load condition is 1.587 GHz. With balanced sensor configuration, interferences from the external environment and fabrication errors for the single‐resonator‐based system can be filtered out and compensated automatically, and thus high precision of the dielectric constant measurement can be achieved. The experiment results of proposed differential dielectric sensor system validate that the measurement accuracy of the dielectric constant can reach an excellent level with a relative measurement error below 0.1%. [ABSTRACT FROM AUTHOR]

The characteristics of the dielectric barrier discharge (DBD) equipped with asymmetrical electrode (ring electrode on the upper and disk electrode on the lower) in atmospheric helium are investigated by a two-dimensional self-consistent fluid model. Simulation results show that as the applied voltage increases, the discharge enhances and the onset of discharge advances, which is similar to the results of traditional DBD. However, with the applied voltage increasing, the symmetry of the discharge current pulses in the positive and negative half cycles disappears because of the asymmetric electrode configuration. In addition, only the spatial distribution of the electron density at the peak moments of the first and second current pulses satisfies the complementary characteristics, while the spatial distribution at other peak moments does not meet the complementary characteristics. Moreover, the electric field, near the upper dielectric barrier surface, presents a curtain-like distribution with considerable radial electric field components, which results from the non-uniform radial surface charge distribution and the ring electrode configuration. The relative variation of the radial distribution of surface charge density is largely determined by the geometry of the opposite electrode. [ABSTRACT FROM AUTHOR]

Time-harmonic transverse-magnetic electromagnetic probing of a grid-like, finite set of infinitely long circular cylindrical dielectric rods affected by missing ones is investigated. Subwavelength distances between adjacent rods and subwavelength rod diameters are assumed, and this leads to a severe challenge due to the need of superresolution within the present microstructure, well beyond the Rayleigh criterion. A binary case is focused on: all rods have the same permittivity, but an unknown number of them are missing, the aim being to detect those within the resulting damaged microstructure from far-field data. Two binary-specialized methods are developed to that effect. One builds upon the iterative contrast-source inversion (CSI) with enforcing a binary contrast inside it. The other is set within a machine learning framework and uses convolutional neural networks (CNNs). The CSI version is mostly used as a reference for the CNN one. Comprehensive numerical simulations in configurations of interest in terms of organization of the microstructure, missing rods, frequency of observation, data acquisition, and noise are proposed. The binary-specialized CNN method appears powerful, upon proper training as expected, and outperforms the binary-specialized CSI method in terms of computational burden, quality of the probing, and versatility. [ABSTRACT FROM AUTHOR]

In order to study the effect of surface morphology of dielectric materials on features of dielectric barrier discharge (DBD) in air at atmospheric pressure (AP), electrical characteristics and optical emission spectrum are obtained in a 2-mm air gap with quartz glass and ceramic used as the dielectric layer (the capacitance of the used dielectrics is similar). The transition of discharge mode is observed for different dielectric material and surface morphology. Results show that with varying dielectric material and surface morphology, air atmospheric pressure dielectric barrier discharge (APDBD) presents three discharge modes, including a filamentary mode, a homogeneous mode, and a mixed mode of them. Further investigation reveals that the homogenous mode is in a Townsend discharge regime, which is realized in a proper surface morphology of 96% Al2O3 ceramic. Moreover, optical emission spectrum is obtained, which mainly consists of atomic lines of nitrogen and molecular bands originating from the second positive system of N2($\text{C}^{3}\Pi _{\mathrm {u}}\to \text{B}^{3}\Pi _{\mathrm {g}}$). From N2($\text{C}^{3}\Pi _{\mathrm {u}}\to \text{B}^{3}\Pi _{\mathrm {g}}$), molecular vibrational temperature is investigated as a function of surface roughness ($R_{\mathrm {a}}$) of the different dielectric materials. Result reveals that there is a minimal vibrational temperature when the discharge is in the homogeneous mode. With quartz glass used as the dielectric, the vibrational temperature decreases first and then increases with increasing $R_{\mathrm {a}}$. The minimum value appears at $R_{\mathrm {a}}$ of 215 nm. Besides, the discharge current is the most concentrated in time, and the discharge looks the most homogeneous under this circumstance. [ABSTRACT FROM AUTHOR]

In this article, a local coupling multitrace domain decomposition method (LCMT-DDM) based on surface integral equation (SIE) formulations is proposed to analyze electromagnetic scattering from multilayered dielectric objects. Different from the traditional SIE-DDM, where the interactions between subdomains are accounted for using global radiation coupling, LCMT-DDM uses a local coupling scheme. The original multilayered object is decomposed into several independent domains, i.e., the exterior region (free space) and many homogeneous interior regions (dielectrics). The boundaries of subdomains are all touching faces, where only the Robin transmission conditions (RTCs) are enforced to ensure the field continuity. Hence, each subdomain only couples with its neighboring regions, which makes the DDM system a highly sparse matrix, especially when the number of subdomains is large. In each subdomain, the electric-field integral equation (EFIE) and the magnetic-field integral equation (MFIE) for dielectrics are used as the governing equations. By imposing RTCs, well-conditioned equations are formed in each subdomain without invoking the combined-field integral equation (CFIE), which usually causes accuracy issues in dielectric modeling. Since the subdomain matrices are diagonally dominant, the flexible generalized minimal residual (FGMRES) technique is used to accelerate the iterative solution of the whole DDM system. Moreover, an effective preconditioner that can be recursively constructed is proposed. [ABSTRACT FROM AUTHOR]

The analytical description of dielectric multipactors requires an accurate physical model. In this article, a nonstationary statistical theory for the analysis of single-surface dielectric multipactors is established by defining an emission-to-emission transition rate and involving all the probability densities related to the emitted secondary electrons. Under the same conditions, the fluctuation of electrons in the evolution process of dielectric multipactors was calculated by the proposed theory and simulated by a commercial particle simulation tool developed based on the Monte Carlo analysis. The calculated results comply well with the simulated ones. Our results also indicated that to obtain an adequate accuracy, at least two random variables, the emission velocity and zenith angle, need to be considered. [ABSTRACT FROM AUTHOR]

The authors are studying the effect of the dielectric choice in electrostatic generators on the energy yield. Despite having high permittivities, solid dielectrics are shown to have a lower performance than is first apparent, due to the effect of the air gap. Liquid dielectrics are found to offer higher overall equivalent permittivities compared to solid dielectrics with air gaps but the conductivity of liquids limits their performance. Experimental work has been conducted using a hybrid generator which incorporates both solid and liquid layers. The solid polyvinylidene fluoride layer is used to limit the conduction between the plates and the liquid dielectric is withdrawn or injected for the necessary change in capacitance. The experimental work has demonstrated a number of design considerations for such generators and is ultimately used to show that energy conversion is possible using this electrostatic generator configuration. [ABSTRACT FROM AUTHOR]

Surface plasmon polaritons (SPPs) propagating along a perfectly electric conducting film with an array of cut-through slits are studied analytically, and both the symmetric and asymmetric dielectric environments of the film are considered. Such a film structure, whether its substrate and superstrate are the same or different, may support a series of SPP modes, whose dispersion relations can be tailored by the film geometry. There exists a fundamental mode without any cutoff in the symmetric film structure, whereas all modes in the asymmetric structure have cutoffs, meaning that even the lowest-order mode can only exist when the film thickness is larger than a certain value. Moreover, for both types of symmetric and asymmetric film structures, the SPP bands do not overlap each other in the frequency domain, so the single-mode propagation is available for each mode. The fields of SPP modes are often highly confined to the structured film when the frequency approaches the asymptotic frequency. [ABSTRACT FROM AUTHOR]

We apply coordinate transformations in the design of waveguides with bent geometry to reduce reflection at the incident port. It was found that in the case of metallic waveguides, by applying the transformation to the medium inside a right-angle bent waveguide, low reflection can be obtained. For the case of dielectric waveguides, this can also be done by applying the same transformation to the bent region containing both the dielectric core and its claddings. Our proposed technique provides an alternative method for designing bent waveguides with low insertion loss. [ABSTRACT FROM AUTHOR]

Solid insulators applying functionally graded material (d-FGM) have spatially non-uniform dielectric properties. The d-FGM insulator is effective on insulation performance improvement without complicating the structure; however, the fabrication of such insulators remains a challenge. To investigate the feasibility of 3D printing technology on d-FGM, we designed and fabricated a conductivity non-uniform insulator and tested its surface flashover characteristics. First, a modified genetic algorithm is employed to design the conductivity distribution in the non-uniform insulator. The designed insulator is then fabricated using a 3D printing process named fused deposition modeling (FDM), in which we verified the applicability of 3D printing materials on electrical insulation. Finally, compared to the uniform insulator, the surface flashover voltages of non-uniform insulators were improved by 23% in SF6 and 20% in vacuum. From above, we envision potential application feasibility for 3D printing of d-FGM in practical insulation design. [ABSTRACT FROM AUTHOR]

Bipolar plasticity for synaptic emulation of indium gallium zinc oxide thin-film transistors (TFTs) with HfOxNy–HfO2–HfOxNy sandwich-stack films as the gate dielectric was investigated. The postsynaptic current increased when a negative pulse train was applied to the gate of TFTs; when a positive pulse was applied, the postsynaptic current was reduced. This result is discussed based on the charge trapping/releasing process with the assistance of ferroelectric behavior of the enwrapped oxygen-deficient-HfO2 layer. The dual response of this synaptic transistor shows promising prospect in the mimicking of biological neurons. [ABSTRACT FROM AUTHOR]

A cationic two-dimensional coordination polymer sustained by a [Ag12S12] cluster secondary building unit has been prepared from a stepwise solid-state reaction. This coordination polymer is capable of associating the anionic dye Congo Red, yielding a composite material that exhibits improved photocurrent and dielectric responses as compared to the pristine polymer. [ABSTRACT FROM AUTHOR]

For advanced electronic device applications including printable, flexible organic electronics and bioelectronics, it is crucial to develop novel dielectric materials with high dielectric strength and low-temperature processability compatible with plastic substrates for producing flexible and low-voltage organic thin-film transistors (OTFTs). Herein, we report the facile fabrication of rationally designed, high-capacitance hybrid gate dielectric films for low-voltage OTFTs on plastic substrates via a room-temperature solution process. To create room-temperature-processed gate dielectrics with high dielectric strength, we designed organic-inorganic hybrid gate dielectric films by including ZrOx networks as inorganic high-k oxide materials for obtaining large capacitance and 1,6-hexanediol diacrylate as a bifunctional UV cross-linking agent and a flexible organic component for increasing the density and flexibility of films and ensuring room-temperature processability. The UV cross-linked ZrOx-based hybrid composite films with a 15 nm thickness showed excellent dielectric properties with a leakage current density of ∼10−6 A/cm2 and a capacitance of 640 nF/cm2. The film surfaces were modified with hydrophobic self-assembled monolayers to match the surface energy of organic semiconductors for enhancing the OTFT performance. The utility of the hybrid dielectrics for flexible OTFTs was demonstrated by realizing pentacene TFTs on plastic substrates with a low operating voltage at –2.5 V, a high on/off current ratio of 105, a threshold voltage as low as –0.7 V, and a hole mobility up to 0.47 cm2 V−1 s−1, which are comparable to those performed on Si substrates. [ABSTRACT FROM AUTHOR]

Increasing light extraction efficiency and narrowing the angular spread of light emitted from optically thick light emitting diodes (LEDs) are desirable but difficult goals to achieve. In this paper, we design, optimize, and fabricate Vogel spiral arrays of dielectric nanostructures for optical directional extraction enhancement of incoherent emission from optically thick phosphor-converted LEDs. In order to design and optimize large-scale structures, we perform a systematic numerical investigation based on full-vector three-dimensional finite difference time domain simulations using a cloud of randomly positioned and randomly phased dipoles that approximate an incoherent Lambertian source. An analytical model based on kinematic scattering is also developed and used to parametrically study changes in the emission profile as the spiral geometry is tuned. The optimal Vogel spiral arrays are fabricated as TiO2 nanodisks atop YAG:Ce3+ blue-to-white converter layers using electron-beam lithography and reactive ion etching. Photoluminescence spectroscopy is used to experimentally measure extraction enhancement up to 2× compared to a flat reference. Finally, accurate Fourier-space (k-space) fluorescence spectroscopy is used to measure the emission intensity profile up to 54° in a single snapshot image, and we find up to a 35% enhancement in power-normalized forward emission compared to a flat reference, under remote laser excitation. The integration of optimized Vogel spiral arrays of dielectric nanoparticles with phosphor-converted LEDs will increase efficiency and narrow the directional spread of light. These effects are beneficial to a variety of active device applications, including imaging, lighting, and projecting devices that require enhanced extraction efficiency combined with directional emission. [ABSTRACT FROM AUTHOR]

A novel Lateral Double-diffused MOS (LDMOS) with an H-shape shallow-trench-isolation (STI) structure is experimentally proposed in this brief. The H-shaped STI can enhance the dielectric reduced-surface-field effect to the n-drift region from multiple directions, making the n-drift deplete more adequately. In this manner, the peak electrical field and the impact ionization rate along the device surface under high drain voltage are clearly decreased, while an additional short current path near the device surface can still be retained. As a result, when the 52-V breakdown voltage is kept, a competitive specific ON-resistance (${R}_{ \mathrm{\scriptscriptstyle ON},\textsf {sp}}$) of 23.9 $\text{m}\Omega \cdot \text {mm}^{\textsf {2}}$ is experimentally achieved using a 0.18- $\mu \text{m}$ BCD process, representing a decrease of 10.5% and 15.9% compared with the conventional split-STI LDMOS and full-STI LDMOS, respectively. The idea can also be generalized to more advanced process nodes. [ABSTRACT FROM AUTHOR]

In this communication, a new multiple-traces Poggio–Miller–Chang–Harrington–Wu–Tsai (MT-PMCHWT) equation is proposed to simulate the electromagnetic scattering from microstrip structures. Based on the surface equivalent principle, the original object can be decomposed into two independent domains, i.e., the exterior region (free space) and interior region (microstrip). Different from the traditional EFIE-PMCHWT method, in this new multiple-traces method, dielectric surface is discretized with two pairs of meshes, and Robin transmission conditions (TCs) are enforced on the interface between the exterior and interior regions to ensure the continuity of fields. In comparison with the traditional EFIE-PMCHWT, this new MT-PMCHWT has a better iteration convergence property. Additionally, a new multiple-traces electric field/combined field integral equation with better iteration convergence is also proposed. Because the continuity of fields is ensured by TCs, the exterior and interior regions can be discretized with nonconformal meshes, which improves the flexibility and efficiency of the proposed methods substantially. [ABSTRACT FROM AUTHOR]

To facilitate better interpretation of dielectric response measurements--thereby directing numerical evidence for condition assessments of oil-paper-insulated equipment in high-voltage alternating current (HVAC) transmission systems--a novel approach is presented to estimate the parameters in the extended Debye model (EDM) using wideband frequency domain spectroscopy (FDS). A syncretic algorithm that integrates a genetic algorithm (GA) and the Levenberg-Marquardt (L-M) algorithm is introduced in the present study to parameterize EDM using the FDS measurements of a real-life 126 kV oil-impregnated paper (OIP) bushing under different controlled temperatures. As for the uncertainty of the EDM structure due to variable branch quantity, Akaike's information criterion (AIC) is employed to determine the model orders. For verification, comparative analysis of FDS reconstruction and results of FDS transformation to polarization--depolarization current (PDC)/return voltage measurement (RVM) are presented. The comparison demonstrates good agreement between the measured and reconstructed spectroscopies of complex capacitance and tan δover the full tested frequency band (10-4 Hz-10³ Hz) with goodness of fit over 0.99. Deviations between the tested and modelled PDC/RVM from FDS are then discussed. Compared with the previous studies to parameterize the model using time domain dielectric responses, the proposed method solves the problematic matching between EDM and FDS especially in a wide frequency band, and therefore assures a basis for quantitative insulation condition assessment of OIP-insulated apparatus in energy systems. [ABSTRACT FROM AUTHOR]

With the advances in two-dimensional (2D) transition metal dichalcogenides (TMDCs) based metal–oxide–semiconductor field-effect transistor (MOSFET), the interface between the semiconductor channel and gate dielectrics has received considerable attention due to its significant impacts on the morphology and charge transport of the devices. In this study, first principle calculations were utilized to investigate the strain effect induced by the interface between crystalline α-Al 2 O 3 (0001)/h-MoS 2 monolayer. The results indicate that the 1.3 nm Al 2 O 3 can induce a 0.3% tensile strain on the MoS 2 monolayer. The strain monotonically increases with thicker dielectric layers, inducing more significant impact on the properties of MoS 2 . In addition, the study on temperature effect indicates that the increasing temperature induces monotonic lattice expansion. This study clearly indicates that the dielectric engineering can effectively tune the properties of 2D TMDCs, which is very attractive for nanoelectronics. [ABSTRACT FROM AUTHOR]

An ultrathin, 5 nm, AlO film grown by atomic-layer deposition was used as a gate dielectric for amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). The AlO layer showed a low surface roughness of 0.15 nm, a low leakage current, and a high breakdown voltage of 6V. In particular, a very high gate capacitance of 70 nF/cm was achieved, making it possible for the a-IGZO TFTs to not only operate at a low voltage of 1V but also exhibit desirable properties including a low threshold voltage of 0.3 V, a small subthreshold swing of 100 mV/decade, and a high on/off current ratio of 1.2χ107. Furthermore, even under an ultralow operation voltage of 0.6 V, well-behaved transistor characteristics were still observed with an on/off ratio as high as 3χ106.The electron transport through the Al2O3 layer has also been analyzed, indicating the Fowler-Nordheim tunneling mechanism. [ABSTRACT FROM AUTHOR]

The continuous scaling and challenges in device integrations in modern portable electronic products have aroused many scientific interests, and a great deal of effort has been made in seeking solutions towards a more microminiaturized package assembled with smaller and more powerful components. In this study, an embedded light-erasable charge-trapping memory with a high-k dielectric stack (Al2O3/HfO2/Al2O3) and an atomically thin MoS2 channel has been fabricated and fully characterized. The memory exhibits a sufficient memory window, fast programming and erasing (P/E) speed, and high On/Off current ratio up to 107. Less than 25% memory window degradation is observed after projected 10-year retention, and the device functions perfectly after 8000 P/E operation cycles. Furthermore, the programmed device can be fully erased by incident light without electrical assistance. Such excellent memory performance originates from the intrinsic properties of two-dimensional (2D) MoS2 and the engineered back-gate dielectric stack. Our integration of 2D semiconductors in the infrastructure of light-erasable charge-trapping memory is very promising for future system-on-panel applications like storage of metadata and flexible imaging arrays. [ABSTRACT FROM AUTHOR]

Dielectric functions of Zn[SUB1-x]Mn[SUBx]O (x≤0.19) thin films were obtained by spectroscopic ellipsometry at room temperature in the 1.5-5 eV photon energy region. A strong absorption structure is observed near 3.1 eV, below the optical band-gap absorption (E[SUB0]) edge, and it does not shift with x. It is interpreted as due to transitions between the crystal-field-split 3d[SUP5] multiplet levels of the tetrahedral Mn[SUP2+] ion that substitute for Zn[SUP2+]. A redshift is observed for the E[SUB0] edge near x=0.06 from that of pure ZnO, interpreted as due to the spin-exchange interaction between d electrons of the Mn[SUP2+] ion and sp electrons near the band gap. The E[SUB0] edge shows a blueshift for larger x. The excitonic character of the E[SUB0] edge is gradually reduced and replaced by a three-dimensional shape as x increases, and this is attributed to increased disorder. [ABSTRACT FROM AUTHOR]

• A thermodynamically-consistent dynamical phase-field model is established. • Negative dielectric permittivity is observed as the applied frequency varies from 30 to 80 kHz. • The electrical polarizations evolve oppositely to the applied field, and it leads to the observed negative permittivity. • Higher damping coefficient or applied in-plane strain can suppress the occurrence of negative permittivity. Unlike the conventional high-frequency dielectric behavior for which the amplitude of the applied field is too small to cause polarization switching, the dynamically-driven polarization reorientation brings remarkable frequency dependence to the nonlinear electromechanical behaviors of ferroelectric nanofilms. In this study, we developed a thermodynamically consistent phase-field model with an introduced second-order kinetic equation to investigate the dynamics of polarization switching in polycrystalline barium titanate nanofilms under high-strength AC fields. The newly introduced kinetic equation consists of an additional dynamic inertial term that brings about collective resonance of polarization within a certain frequency range. Negative dielectric permittivity is observed in a certain frequency band as the applied frequency varies from 30 to 80 kHz, and the maximum absolute value is reached around 40 kHz. It was demonstrated through microstructure-based analysis that such negative dielectric behavior is inherited from the frequency-dependent polarization switching in the nanograins. It also serves as the mechanism for other observed frequency-dependent physical properties, e.g., the remnant polarization, the piezoelectric coefficient at zero electric field and the coercive field. In addition, we further explored the influence of the damping coefficient in the kinetic equation and the influence of the in-plane strain to such frequency-dependent behaviors. It was found that a higher damping coefficient or applied in-plane strain tends to weaken the occurrence of negative permittivity. [ABSTRACT FROM AUTHOR]

PbLaBa[(ZrSn)Ti]O (PLBZST) antiferroelectric (AFE) ceramics were fabricated via the traditional solid-state ceramics processing method and the pulsed discharging current waveforms were measured under different electric fields. The discharging current of the AFE ceramic with an area of only 15 mm could be as high as 50 A under 2.8 kV/mm. The analysis of hysteresis loops, dielectric constant under DC bias electric field and the discharging current waveforms indicate that the AFE dielectrics are almost linear under low electric field but show remarkable nonlinearity under high electric field. Under 2.8 kV/mm, 0.33 J/cm energy could be released from the stored 0.47 J/cm energy. The discharging efficiency is 70 %. [ABSTRACT FROM AUTHOR]

Block copolymers poly( endo- N-3,5-bis(trifluoromethyl)biphenyl-norbornene-pyrrolidine)-block-poly( exo- N-(cinnamoyloxyethyl)-7-oxanorborn-5-ene-2,3-dicarboximide) ( endo- PTNP- b- exo- PCONBI) and poly( exo- N-3,5-bis(trifluoromethyl)biphenyl-norbornene-pyrrolidine)-block-poly( exo- N-(cinnamoyloxyethyl)-7-oxanorborn-5-ene-2,3-dicarboximide) ( exo-PTNP- b- exo-PCONBI) were synthesized by ring-opening metathesis polymerization. The endo- or exo- PTNP served as the high dielectric functional chain, and exo- PCONBI acted as the crosslinking segment. The endo- PTNP- b- exo- PCONBI, in which endo- PTNP has a high content of trans double bond and adopts isotactic configuration, shows a dielectric constant ( ε) of 15.5, whereas exo- PTNP- b-exo- PCONBI, in which exo- PTNP has 67% trans double bonds and atactic microstructure, displays relatively low ε of 7.1. The cinnamate groups in exo- PCONBI were crosslinked to form three-dimensional network by cycloaddition reaction under UV irradiation. Exposed to UV-light for 10 min, the cinnamate group in polymer films has a crosslinking conversion of 36%, as determined by UV-Vis absorption measurements. By photocrosslinking, the polymer film has an increased ε of 16.6, a dielectric loss of 0.03, an elevated glass-transition temperature of 137 °C, and an enhanced decomposition temperature of 405 °C, compared to those of polymer films without irradiation. [ABSTRACT FROM AUTHOR]

A methodology to generate a circular TE13 mode for the operation of high-order mode (HOM) gyrotron-traveling-wave tubes is presented in this paper. A rectangular TE10 mode is efficiently converted into a circular TE13 mode using Y-type power dividers. Symmetric curved lossy dielectrics and dielectric rings are, respectively, positioned to suppress the potential coupling TE32 and TE71 modes according to their electric and magnetic field distribution properties. An HOM converter without dielectrics loaded was designed, constructed, and cold tested. Back-to-back transmission measurements exhibit good agreement with the results of computer simulations. [ABSTRACT FROM AUTHOR]

• Nitrogen-rich cobalt-doped carbon with different morphologies was successfully prepared. • Adjusting the morphology of MOF to regulate the permittivity of pyrolysis products. • A absorption bandwidth ∼ 5.52 GHz is realized with a thin thickness (2.1 mm). Accordion-like nitrogen-doped carbon was synthesized through MOF structural engineering, unlocking the full microwave attenuation potential of the material and achieving ultra-efficient microwave absorption performance. By modulating the structure of the ZIF precursors, better impedance matching and more interfacial polarisation is achieved in their derived carbon materials. As a result, the product has a minimum reflection loss of − 45.2 dB at 2.0 mm and an absorption bandwidth of 5.52 GHz at 2.1 mm, exhibiting an excellent specific reflection loss compared to the vast majority of previous absorbers derived from MOFs. [ABSTRACT FROM AUTHOR]