CSRR-based resonator for complex dielectric permittivity measurements up to 35 GHz

Understanding hydrological, agricultural, and environmental processes in soils relies on accurately measuring volumetric water content (θ), matric potential (h), and hydraulic conductivity (K). These parameters are fundamental for quantifying plant-available water, optimizing irrigation scheduling in precision agriculture, modeling watershed responses, and studying the impacts of climate change in complex ecosystems. Among these parameters, θ is truly indispensable, as it represents the primary indicator of the water status of soils and a prerequisite for interpreting the other hydraulic variables. In recent years, capacitive sensors have become one of the most widely adopted technologies for θ estimation, owing to their favorable balance between accuracy, robustness, and affordability. These sensors infer soil moisture by measuring dielectric permittivity of soils, which is strongly governed by water content, making them particularly suitable for distributed monitoring and IoT-based environmental applications. The present study aimed to develop a low-cost capacitive sensor for θ estimation. This sensor can be made using 3D printing technology combined with conductive, nickel-based paint, which (once applied on the 3D-printed guides) forms the capacitive electrode. The capacitive component operates at an operational frequency of 60 MHz. The system was subjected to a rigorous testing protocol, including calibration and validation phases under laboratory conditions using three soils of different textures. Its performance was specifically compared with the time-domain reflectometry (TDR) technique, which is widely recognized in Soil Physics and Soil Hydrology as the reference method for θ estimation due to its reliability and accuracy. These tests confirmed the effective performance of the proposed sensor, which overall exhibited good reliability within the selected validation range, corresponding to a θ range of 0 to 0.40 cm3/cm3.

In this study, barium titanate (BT) and polyaniline (PANI) nanocomposites with different BT:PANI ratios (80:20, 70:30 and 60:40) as well as pure BT were processed, and their structural, morphological and dielectric characteristics were examined. When the content of PANI was increased, X-ray diffraction showed a systematic improvement in the crystallite size (40–64 nm) and strain (0.0007–0.0029) in the following order: pure BT < BT:PANI 80:20 < BT:PANI 70:30 < BT:PANI 60:40. Scanning electron micrographs showed a clear coral-like shape, confirming successful composite-formation and interaction with one another. The FTIR spectra demonstrated the coexistence of PANI's quinoid and benzenoid ring vibrations with BT's Ti–O stretching modes. Additionally, dielectric permittivity studies showed that as PANI's amount increased, the real permittivity got enhanced, thereby indicating a better charge storage capacity and losses were reduced. These results underscore that modifying BT with PANI by nanocomposite formation can enhance structural and dielectric performance, making them attractive for battery applications.

The study reports structural and electrical evolution in La3+/Mn3+ cosubstituted BaTiO3, with compositions LaxBa1-xMnxTi1-xO3 (x = 0.00-0.50) in search of lead-free energy storage materials. Solid-state synthesized samples were thoroughly characterized by XRD, Raman spectroscopy, XPS, SEM, AC-impedance, and P-E measurements. Structural analysis revealed a tetragonal-to-rhombohedral (T to R) phase transition with increasing substitution, accompanied by lattice distortion and reduced tetragonality. Raman spectroscopy could clearly delineate R-type modes in otherwise single-phasic (T) La0.05Ba0.95Mn0.05Ti0.95O3. XPS confirmed mixed valence states of Mn (Mn2+/Mn3+) and O-vacancies which influenced structural and electrical behavior. Introduction of 2 mol % La3+/Mn3+ led to doubling of dielectric permittivity, K (∼1205), relative to BaTiO3. This is attributed to plausible distortion in BaO8/TiO6 polyhedra caused by occupancy of the same lattice sites by ions of varying sizes and oxidation states. The composition La0.05Ba0.95Mn0.05Ti0.95O3 showed an almost frequency-independent K (∼400) and low dielectric loss (0.05). LaxBa1-xMnxTi1-xO3 (x ≥ 0.1) yielded lossy, conduction-dominated behavior consistent with defect-facilitated ion transport. Simultaneous occurrence of ferroelectricity and visible band gap (2.23 eV) in La0.02Ba0.98Mn0.02Ti0.98O3 proposes a potential ferroelectric-photovoltaic material. These results establish La/Mn codoping in BaTiO3 as an effective strategy to yield ferroelectrics, low-loss dielectrics, and conductors by composition-driven structural tailoring.

ABSTRACT Polyvinylidene fluoride (PVDF) is a functional polymer with highly desirable electrical and piezoelectric properties. Optimizing its piezoelectric performance requires modifications to its morphology, composition, and electrical characteristics. Plasticizers are commonly known to improve flexibility in polymer materials and are used to facilitate ion transportation in electrolytes, increasing the conductivity. However, inclusion of plasticizer to enhance piezoelectric behavior, primarily by adding flexibility, facilitating better dipole orientation and consequently inducing higher piezoelectricity, was little explored. This study investigates the effect of the addition of ethylene carbonate (EC) as a plasticizer on the piezoelectric performance of PVDF. The PVDF/EC films using the spin‐coating method were fabricated with different concentrations of EC loading (from 1 to 9 wt.%). The morphology of the prepared samples was investigated using scanning electron microscopy (SEM) and polarized microscopy studies. The crystalline structure and phase changes were analyzed using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and Raman spectroscopy. The thermal behavior of the samples was analyzed through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The electrical permittivity under different DC frequencies was investigated using an LCR meter. First of its kind, the incorporation of EC plasticizer demonstrates an enhancement of the β‐phase due to inter‐molecular bonding between the carbonyl group from EC and the hydrogen atom from PVDF, which is crucial for improved dielectric properties. The experiment proves the ability of EC to modify the crystalline structure of PVDF with only polymorphism, which is possible with 2 wt.% of EC in PVDF at 120°C of annealing temperature. These findings establish the potential of plasticizer integration as a cost‐effective methodology for applications in sensors and energy storage devices.

Addressing the requirements of advanced capacitor applications for high dielectric permittivity, low loss, and strong frequency stability necessitates the accelerated development of materials exhibiting weakly coupled relaxor ferroelectric characteristics and broad temperature stability. BaTiO3 systems have attracted considerable interest owing to their high dielectric constant and tunable properties. However, conventional trial-and-error approaches and complex doping strategies hinder rapid progress. In this study, a data-driven approach combining first-principles calculations with machine learning was employed to predict the variation trends in formation energies for 30 301 Sr, La co-doped BaTiO3 compositions. The ferroelectric properties, crystal structures, elastic anisotropy, and thermal properties were systematically investigated at four representative doping levels (0, 0.125, 0.25, and 0.375) to elucidate the microscopic mechanism responsible for the emergence of weakly coupled relaxor ferroelectric behavior and to enable rapid identification of doping ranges that yield both relaxor ferroelectric characteristics and broad temperature stability. The results show that Sr, La co-doping in the range of 0.125–0.25 introduces compositional and displacement disorder that progressively suppresses long-range ferroelectric order, promotes the formation of polar nanoregions, and drives the system toward a weakly coupled, relaxor-like dielectric response with reduced hysteretic loss, with the composition at 0.25 exhibiting enhanced mechanical and thermodynamic performance. These findings provide guidance for BaTiO3-based materials for high-frequency capacitor applications and offer a transferable framework for accelerating the study of doped material properties.

The interfacial layers appearing in low-dimensional ferroelectric devices due to polarization fluctuations near electrodes could destabilize spontaneous polarizations and reduce dielectric permittivity significantly. But they can conversely work as embedded selectors in high-density ferroelectric LiNbO3 crossbar memories when the interfacial domains are volatile. In contrast, the digital data stored in the nearby intrinsic domains are nonvolatile. The stored data can be nondestructively read out through on/off currents following through erasable conducting domain walls between two antiparallel/parallel domains. However, the intrinsic physics how to adjust the onset voltage of the selector is still unclear. Here, we fabricated the mesa-like cell in contact with two side electrodes at the surface of a monodomain LiNbO3 single crystal and found the selection functionality of the interfacial layer near the head of the pristine domain. The onset voltage of the selector proportional to the interfacial-layer thickness can be continuously modulated by the tilted angle of the electrode projected along the domain orientation, unlike the electrode in the tail that cannot change the onset voltage. It is believed that the volatile domain within the interfacial layer arises from an imprint field built up by trapped electrons in compensation of the opposite domain boundary charge near the head. The designed electrode geometry provides guidance to integrate the high-density LiNbO3 crossbar memory.

Abstract We report the observation of a phase transition in a KTaO$_3$ crystal, corresponding to a paraelectric-to-ferroelectric transition. The crystal was placed inside a copper cavity to form a dielectric-loaded microwave cavity, and the transition was observed to occur near 134 K. As the cavity was cooled, the frequencies of both transverse electric and transverse magnetic resonant modes decreased (corresponding to an increase in permittivity). The mode frequencies converge at the transition temperature (near 134 K) and, below this point, reverse their tuning direction, increasing their frequency with decreasing temperature. This behaviour corresponds to a decrease in dielectric permittivity and is atypical for pure KTaO$_3$. To investigate further, we conducted impurity analysis using Laser Ablation inductively coupled mass spectrometry (LA-ICPMS), revealing a significant concentration ($\sim$ 7\%) of niobium (Nb) in the crystal. This suggests that the observed phase transition is driven by residual Nb impurities, effective as KTN, which induce ferroelectricity in an otherwise paraelectric host. Similar crystals with a lower concentration ($&lt;$ 2\%) did not undergo a phase transition but exhibited a loss peak at this temperature. These findings have practical implications for the design of tunable devices, for example, resonator-based dark matter detectors, where low-loss material phase stability and tunability are crucial.

Conventional electrochemical mechanisms for electrical energy storage face fundamental limitations in achieving ultra-high energy density and high-power output. These constraints arise from the intrinsic nature of the electrochemical processes themselves. Overcoming this challenge requires a paradigm shift—from electrochemical to quantum mechanisms of energy storage. As shown by theoretical models, this concept can be implemented in nanostructured materials consisting of clusters with tunnel-transparent shells. It is possible to build such a structure using supramolecular complexes and clathrate organization of matter. For this purpose, we synthesized a supramolecular clathrate with a hierarchical sub-host&lt;host&lt;guest&gt;&gt; architecture and investigated its conductive and polarization properties using impedance spectroscopy. As shown by the results of the research, in this structure it was possible to combine a high value of the dielectric permittivity with a dielectric loss tangent below unity in the ultra-low-frequency range. This was facilitated by the presumably specific energy structure of the clathrate, as evidenced by the measured spectra of thermally stimulated discharge currents. The ability of the clathrate to accumulate an electric charge is evidenced by the measured hysteresis current-voltage characteristic. The value of the specific capacitance of this clathrate reaches the value that arises from the theoretical model of a quantum supercapacitor.

A new family of block copolymer electrolytes, where the "soft" block is synthesized via anionic ring opening copolymerization of ethylene oxide (EO) and glycidyl methyl ether (GME) and the "hard" block is glassy polystyrene (PS), overcomes many of the limitations of poly-(ethylene oxide) (PEO) for battery applications. Two block copolymer systems, PS-b-P-(EO-co-GME) with a GME content of 21% and PS-b-PGME containing a pure PGME block, were prepared, both with narrow dispersity (Đ = 1.03-1.15). All polyether blocks are structural isomers of PEO. Yet, in both structures, the polyether block is fully amorphous at all temperatures. When doped with LiN-(SO2CF3) (LiTFSI) at different ratios, the materials provide superior dc-conductivity values in comparison to the established dual ion conductors PS-b-PEO doped with LiTFSI or with LiCF3SO3 (LiTf). In addition, PS-b-PGME doped with (LiTFSI) has a higher conductivity (∼1 × 10-5 S·cm-1 at the PS glass temperature) than PS-b-P-(EO-co-GME) and a higher conductivity than the structurally similar single ion conductor polystyrene-b-poly-(ethylene oxide-co-(lithium trifluoromethane-sulfonamide)-ethyl glycidyl ether) (PS-b-P-(EO-co-LiTFSAEGE). PGME best combines favorable properties required for the design of the soft block in SPEs based on block copolymers: low liquid-to-glass temperature (T g) nearly independent of molar mass, favorable molecular structure that can solubilize alkali metal salts, higher dielectric permittivity than PEO, and the absence of crystallization. These results suggest that PGME or PGME-containing polyether copolymers can replace PEO as the "soft" block in future SPEs.

Understanding the optical properties of astrophysical ices is crucial for modeling dust continuum emission and radiative transfer in dense, cold interstellar environments. Molecular nitrogen, a primary carrier of N in protoplanetary disks, plays a key role in the formation of nitrogen-bearing species. However, the lack of direct measurements of the terahertz (THz) to infrared (IR) optical constants of ice introduces uncertainties in radiative transfer models, snow-line locations, and disk mass estimates. N2 We present direct measurements and analysis of the optical properties of ice across a broad THz--IR spectral range by combining THz pulsed spectroscopy (TPS) and Fourier-transform IR (FTIR) spectroscopy. The observed optically active THz vibrational modes of ice are supported by density functional theory (DFT) calculations. The consistency of our measurements and calculations with datasets from the literature is also assessed. N2 N2 N2 ice was grown at cryogenic temperatures via gas-phase deposition onto a cold silicon window. The optical properties of the ice samples were quantified using our earlier-reported method: it involves the direct reconstruction of the THz complex refractive index from the TPS data, combined with the derivation of the IR response from the FTIR data using the Kramers-Kronig relations. The ice response was parameterized using the Lorentz model of complex dielectric permittivity, which was verified with our DFT calculations and compared with the literature data. N2 The complex refractive index of ice is quantified in the frequency range ν = 0.3--16 THz (the wavelength range łambda = 1 mm--18.75 μm), and was compared with the DFT results as well as with the available literature data. The observed resonant absorption peaks at ν_ = 1.47 and 2.13 THz; the damping constants of γ_ = 0.03 and 0.22 THz, respectively, are attributed to the well-known optically active phonons of the α- crystal. N2 L L N2 We provide a complete set of THz--IR optical constants for ice by combining TPS and FTIR spectroscopy. Our results have implications for future observational and modeling studies of protoplanetary disk evolution and planet formation. N2

We have synthesized CaCu3Ti4O12 using a green synthesis route, employing an oxalate precursor obtained from a mixture of Averrhoa carambola (star fruit) fruit juice and aloe vera extract. The structural, microstructural, and ac electrical transport characteristics of this material were examined at high temperatures from 308 to 773K and in a wide frequency window of 100Hz to 1MHz. The Rietveld refinements of X-ray diffraction (XRD) and Raman spectroscopy demonstrate a single-phase body-centered cubic crystal structure with space group Im-3, and Ag and Fg vibrational modes due to rotations of TiO6 octahedra and Ti-O-Ti anti-stretching vibrations in CaCu3Ti4O12. The fitted Nyquist plots ([Formula: see text] at different temperatures exhibit the grain and grain boundary contributions, and the semicircles shrink at higher temperatures, which disclosed the negative temperature coefficient of resistance (NTCR) behavior. Both grain (Rg) and grain boundary resistance (Rgb) and capacitances (Cg, Cgb) diminished with temperature, and their activation energy was estimated to be ~ 0.56eV and ~ 0.84eV, respectively. The ac electrical conductivity increases with frequency and temperature due to thermally activated charge carriers, and the frequency exponent (n) remains nearly constant at low temperature region (quantum mechanical tunneling model) and decreases after 573K (correlated barrier hopping model). Their dc activation energy was determined to be 0.51eV and 0.62eV, respectively. High dielectric permittivity ([Formula: see text]) ~ 9458 and low dielectric loss (δ) ~ 0.308 were observed at 308K and frequency 100Hz, and both values increase with the evolution of temperatures and quantify a higher ability to store the electrical charges in an electric field. The dielectric relaxations at various temperatures are associated with the Maxwell-Wagner (MW) type polarization, and the distribution of relaxation behavior or Cole-Cole parameter (α) divulged a non-ideal Debye type broader and symmetric distribution with temperatures. The modulus spectra help us to comprehend the origin of the giant dielectric constant and strong interfacial polarization by highlighting the grain and grain boundary contributions. The high dielectric constant, low loss, and high temperature stability recommend its promising applications in several electronic, energy, and sensing applications.

Solution casting was used to create GO/PVA/AgNW nanocomposites, which were then exposed to gamma irradiation at dosages of (8, 25 and 50) kGy. XRD, SEM, XPS, and dielectric spectroscopy were used to examine the nanocomposites’ structural, morphological, and dielectric characteristics. XRD analysis confirmed the successful synthesis of the nanocomposites and indicated that no significant oxidation occurred due to -irradiation. Interestingly, the sample exposed to 25 kGy radiation showed the lowest degree of crystallinity. With no discernible morphological changes across all irradiation doses, SEM images revealed a homogeneous dispersion of GO inside the polymer matrix and a random distribution of AgNWs throughout the composite. XPS results demonstrated that silver retained its metallic state, while gamma irradiation enhanced its surface contribution. Dielectric measurements revealed that the sample irradiated at 8 kGy exhibited the highest dielectric permittivity and electrical conductivity. This response is fundamentally linked to the increased freedom of charge carriers, a consequence of polymer chain scission processes and the simultaneous introduction of oxygenated functional moieties. These structural modifications facilitate easier charge transport pathways within the composite matrix.

Dielectric permittivity mixture models often assume simplified rock geometries, limiting their accuracy in rocks with complex pore structures. Systematically evaluating the influence of pore geometry, grain shape and grain size on model performance for water-saturation assessment is experimentally challenging and thus largely untested. Frequency-domain dielectric permittivity simulations, however, provide a means to effectively model these geometrical influences at the pore scale. Therefore, this paper aims to: (1) investigate the influence of grain geometry (size, shape and alignment) on dielectric permittivity using synthetic samples; and (2) evaluate the mixture model performance in assessing water saturation in synthetic and actual rocks. We performed frequency-domain simulations in the frequency range of 10 Hz–5 GHz. The dielectric permittivity dispersion significantly increased as grains flattened (i.e. the aspect ratio increased). The frequency-domain simulations conducted over the range of 10 MHz–5 GHz showed that grain size had a negligible impact on permittivity above 10 MHz. We observed that the relative permittivity in the z direction decreased with an increased aspect ratio of the grains. Simulations suggested that directional permittivity measurements can enhance grain-shape characterization. The unique contribution of this paper is the comprehensive quantification of the impacts of grain size, shape and alignment on the dielectric permittivity. Conducting such an investigation is challenging and almost impossible in the core-scale domain.

Abstract The influence of strontium oxide (SrO) doping on the structural, microstructural, and terahertz (THz) dielectric properties of Al 2 O 3 ceramics is comprehensively investigated. Pure and SrO-doped Al 2 O 3 samples are fabricated and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and THz time-domain spectroscopy (THz-TDS). XRD analysis reveals the formation of SrAl 12 O 19 secondary phases for doping levels of 0.3 vol% and above, while SEM observations indicate significant densification and grain refinement, particularly for the 0.3-vol% SrO composition, which exhibit the highest relative density and the most uniform microstructure. THz-TDS measurements demonstrate that SrO doping strongly affects the refractive index, absorption coefficient, dielectric permittivity, and loss tangent in a non-linear manner. All doped samples exhibit an increase in refractive index and permittivity compared to the pure Al 2 O 3 , whereas the absorption and dielectric losses are highly dependent on the microstructural quality and secondary-phase content. The 0.3-vol% SrO-doped ceramic shows the most favorable THz response, characterized by reduced absorption coefficient (&lt; 20 cm− 1 ), and the lowest loss tangent (&lt; 0.03), indicating minimal extrinsic scattering and optimized densification. In contrast, the 0.1-vol% composition exhibited higher losses due to insufficient microstructural refinement, while the 0.5-vol% samples display moderate losses associated with increased SrAl 12 O 19 phase formation. Overall, the results demonstrate that SrO dopants play dual role in tailoring the THz dielectric response of Al 2 O 3 ceramics. These findings highlight the potential of SrO-doped Al 2 O 3 ceramics as promising materials for 5G/6G and millimeter-wave device applications, and sensing systems where low-loss and structurally stable components are essential.

Enhancing structural, optical and electrical properties of carboxymethyl cellulose/sodium alginate hybrid polymer films with CoCl2 for solid-state battery applications.

ABSTRACT In the present study, we fabricated and characterized ternary hybrid fillers of conductive carbon black (CCB), carbon nanotubes (CNT), and reduced graphene oxide (RGO) reinforced natural rubber (NR) composites. The ternary filler system exhibited good filler‐polymer interaction as observed from the cure characteristics and mechanical properties. We used impedance analysis to study the dielectric permittivity and associated polarization mechanisms, and the AC conductivity was fitted using the Jonsher Power law. The presence of functional groups on the ternary nanofiller surfaces caused increased filler‐filler interactions, leading to the formation of an excellent conductive network. Mechanical and viscoelastic studies revealed the reinforcing effect of the CCB, CNT, and RGO fillers. The theoretical models, such as Nicolais‐Narkis and Turcsanyi, were employed to predict the tensile strength. Morphological analysis confirms the homogeneous dispersion of filler in the matrix. The present system also demonstrated excellent electromagnetic interference (EMI) shielding performance, with the highest shielding effectiveness (SE) values of 37.4 and 35.3 dB at 12 GHz for the ternary composites, satisfying commercial requirements.

Magnetic induction technology (MIT), as a non-contact and non-invasive sensing approach, has shown great potential for detecting brain lesions since it is unaffected by skull shielding. However, most MIT-based studies on intracerebral hemorrhage (ICH) have mainly focused on identifying the presence or estimating the volume of bleeding, while research on spatial localization has remained limited. In this study, a magnetic induction differential localization (MIDL) method was proposed to detect and localize ICH. A pair of symmetrically arranged detection coils was designed to sense the differential magnetic field perturbations caused by variations in the electrical conductivity and permittivity of brain tissues. The feasibility and response characteristics of the system were verified through numerical simulations and physical phantom experiments, followed byin vivovalidation on eight New Zealand white rabbits with unilateral induced hemorrhages. The real and imaginary components of the differential signals were analyzed to investigate their correlation with the side and volume of hemorrhage. Both simulations and phantom experiments demonstrated opposite variation trends of the real and imaginary components for left- and right-side hemorrhages. Animal experiments further confirmed that, after the injection of 1 ml of blood, the signal variation amplitudes significantly exceeded the baseline deviation (P < 0.05), exhibiting opposite directions of change between the two hemispheres. These results indicate that the proposed MIDL method can effectively distinguish the hemorrhage side and provide a theoretical and experimental foundation for non-invasive localization of intracerebral hemorrhage using MIT.

Abstract The dielectric permittivity is a crucial parameter in planetary ground-penetrating radar (GPR) missions, such as the RIMFAX radar onboard the Mars 2020 Perseverance rover. It characterizes subsurface materials and enables depth interpretation of radargrams. In this study, we develop a deep learning–based approach for inverting dielectric permittivity from Radar Imager for Mars’ Subsurface Experiment (RIMFAX) GPR data. The architecture integrates a convolutional neural network, Bi-LSTM, and a self-attention mechanism, providing a principled framework for leveraging the sequential nature of GPR echoes, capturing long-range subsurface dependencies, and enhancing both the robustness and accuracy of inversions. The input is 1D processed GPR data, and the output is the corresponding 1D dielectric permittivity profile. By combining multiple 1D dielectric permittivity profiles, complex 2D profiles can be constructed. A large volume of synthetic data is used to train the model, allowing it to directly capture the intrinsic relationship between GPR data and dielectric permittivity. The approach is validated on the test set and then applied to the RIMFAX GPR data acquired by the Perseverance rover on Sols 389 and 770. The prediction results effectively reveal key characteristics of the subsurface sedimentary structure, including the number of layers, thicknesses, and the geometry of their contacts. It is broadly consistent with findings reported in prior research, demonstrating the great potential and promising applicability of the approach for dielectric permittivity inversion. However, in such complex planetary radar data, the true dielectric permittivity remains uncertain, and caution is therefore required when using permittivity estimates to infer subsurface structure.

The continuous scaling of semiconductor devices necessitates the integration of high-permittivity (high-k) dielectrics to maintain gate control and reduce power consumption. Here, we report an ultrahigh dielectric constant (k) of ∼150 in ultrathin (10 nm) β-gallium oxide (β-Ga2O3) metal-insulator-metal capacitors. Photoresponse and microstructural analyses link the giant permittivity to an oxygen vacancy (VO)-ordered phase. The fabricated capacitors exhibit excellent performance for memory applications, including low dielectric loss (<0.02 at 100 kHz), low leakage current (<10-7 A/cm2), high operating speed (>20 MHz), and high endurance (>1010 cycles). To validate practical utility, MoS2 field-effect transistors gated by β-Ga2O3 were fabricated, exhibiting a high on/off ratio (>106), a low subthreshold swing (SS) of 68.1 mV/dec, negligible hysteresis (5.8 mV), and ultralow gate leakage (∼10-13 A). These findings establish ultrathin β-Ga2O3 as a compelling high-k material for next-generation logic and memory devices.