Journal of Electronic Materials最新文献

High leakage current density and relatively low piezoelectric activity have become one of the main obstacles to expanding the practical application of Bi₄Ti₃O₁₂ (BIT) high-temperature piezoelectric ceramics. Although ion doping can improve electrical resistivity and piezoelectric response, it often lowers the Curie temperature. In this work, by introducing CaBi₂Nb₂O₉ (CBN) with higher Curie temperature to BIT, a composite ceramic (1−x)BIT-xCBN was designed, and the effect of CBN content on the structure and electrical properties of the ceramics was investigated. With the increase in the x value, the intensity of the highest peak (117) gradually decreased until disappearing, while the intensity of peak (115) gradually increased, and the X-ray diffraction (XRD) refinement results showed that some non-stoichiometric compounds, Bi_1.74Ti₂O_6.624 and Ca_0.5Bi_2.5Ti_0.5Nb_1.5O₉, were produced. The sheet-like grains were effectively suppressed, while the granular grains became prominent with high CBN doping content, which should contribute to improving the electrical resistivity of ceramics. The optimal electrical properties were obtained in 0.8BIT-0.2CBN composite ceramics as follows: the piezoelectric coefficient d₃₃ = 13.8 pC/N, the Curie temperature T_C = 765°C, and the electrical resistivity ρ_dc = 8.52 × 10⁵ Ω·cm (@ 500°C). In addition, the d₃₃ maintained 89.1% of the initial value after annealing at 550°C, showing good thermal stability for high-temperature sensing applications.

Indium-doped zinc oxide (ZnO:In) thin films were prepared using the spray pyrolysis technique, and the effects of indium concentration on the structural, optical, electrical, and sensing properties of the ZnO:In films were investigated. The indium concentration was varied between 0 wt.% and 15 wt.%. The results show a polycrystalline structure for all layers using x-ray diffraction. The lowest sheet resistance of approximately 120 Ω/□ was achieved with an indium concentration of 5 wt.% in the starting solution. The morphological properties of the thin films were investigated using field-emission scanning electron microscopy. The results indicate that an increase in the indium concentration disrupts the nano-granular structure of the surface, the surface becomes wrinkled, and a snowflake-like pattern is formed on the surface of the thin film. The ethanol sensing properties of the samples were studied using an electric circuit. Sensing parameters including the dynamic response, sensitivity, and response/recovery times of the samples were investigated. For an ethanol concentration of 200 ppm, the gas response of the pure ZnO layer was about 1.05. An increase in the indium concentration to 15 wt.% was found to improve the gas response of the samples. For an ethanol concentration of 200 ppm, the gas response of the ZnO:In (15 wt.%) layer increased to 1.82.

This work reports the synthesis and characterization of a zinc-based metal–organic framework (Zn-MOF) and its nanocomposite with graphene oxide (GO) for room-temperature ammonia (NH₃) sensing. The Zn-MOF/GO nanocomposite was prepared via an innovative solvothermal approach and comprehensively characterized using x-ray diffraction, UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and thermogravimetric analysis. The nanocomposite demonstrated exceptional NH₃ sensing performance at ambient conditions, exhibiting a linear response from 20 ppm to 220 ppm, a significant 13.2% response towards 100 ppm NH₃, and rapid response/recovery times of 102/127 s. Notably, the sensor maintained long-term stability, with 12.4% average sensitivity over 50 days. The synergistic effects between GO and Zn-MOF components, coupled with the high surface area and porous structure, contributed to the superior sensing characteristics. A strong linear correlation (R² = 0.9906) between sensor response and NH₃ concentration enabled precise quantitative detection. This study not only introduces a novel material for NH₃ sensing but also provides crucial insights into the structure–property relationships governing nanocomposite gas sensors. The findings open new avenues for designing high-performance chemiresistive gas sensors operating at ambient conditions, with potential applications in environmental monitoring and industrial safety.

A straightforward and one-step modification of the pencil graphite electrode was performed using co-polymerization of diphenyl amine-4-sulfonic acid (DPASA) sodium salt, and 4-vinylpyridine (VP), and also simultaneous formation of ruthenium dioxide nanoparticles (poly(DPASA-co-VP)-RuO₂ NPs/PGE). The subsequent step involved the application of the altered electrode to examine the quantity of sumatriptan by employing a highly sensitive adsorptive differential pulse voltammetric method. The modified electrode was thoroughly characterized through the utilization of cyclic voltammetry (CV), field-emission scanning electron microscopy (FESEM), and electrochemical impedance spectroscopy (EIS). Under optimized conditions, the concentration of sumatriptan was determined within two linear ranges: 1.0–50.0 nM and 50.0–5000.0 nM, with a detection limit of 0.03 nM. Ultimately, the suggested approach was employed to gauge the sumatriptan content in tablet and urine samples, revealing that this method possesses the requisite levels of accuracy and precision.

The thermopile of the sensor consists of 192 pairs of Pt-PtRh10 thermocouples with length 1 mm and width 100 μm in serpentine series were deposited on Al₂O₃ ceramic substrates by a photolithography coating process. The thermal resistance layers with the proposed low thermal conductivity feature a meshed cavity structure, with four thermal resistance layers spaced over the thermopile contacts to enhance the sensitivity of the sensor. Calibration of the sensor’s sensitivity was performed by a flat-plate radiative heat flux device, while its response time was measured by a pulsed laser. Finally, the sensor’s performance in an actual application environment was simulated using a wind tunnel. The results showed that the thin-film heat flux sensor can operate in environments ranging from 200°C to 1500°C, with a sensitivity of 0.03067 m² μV/W, the maximum relative error was 8.5% with an average response time of 12.7 μs. The sample exhibited stable performance during wind tunnel testing, responding quickly to changes in heat flux.

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Pipeline leaks are known to frequently occur in chemical processing and urban gas pipes, which can lead to equipment damage, explosions, and potentially serious injuries. A design of a piezoelectric acoustic sensor for fluid leak detection is proposed in this work. The low-frequency acoustic leak signals that travel through the fluid in a pipeline can be detected using a piezoelectric acoustic sensor. The design and simulation of sensor is done using COMSOL Multiphysics software. The sensor specification is used to guide the choice of materials and optimization of geometry. The simulated results show the characteristics of transient response using a nondestructive detection approach at various leakage rates. The recommended detection method's ability to detect leak signals with tolerable accuracy is shown through simulated results. The designed sensor can be used for both long-term leak monitoring and short-term safety evaluations. The simulated sensitivity of 191 µV/m at 27.46 kHz resonance frequency is achieved by optimizing device design. The maximum deflection at the center is 2.37 nm. The total electric energy generated at 1 N of force and 5 Hz frequency is 8 nJ.

In this work, we investigated the impact of Mn substitution on the morphological, structural, and optical properties of barium strontium titanate (BST) with the formula Ba_0.92Sr_0.08Ti_1−xMn_xO₃ (x = 0.00, 0.10, 0.20) fabricated using the solid-state reaction technique. The morphological and structural properties were studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The optical properties of the samples were analyzed using photoluminescence (PL), Fourier transform infrared (FTIR), and Raman spectroscopy. SEM micrographs displayed nearly spherical grains. The phase formation, lattice structure, crystallite size (D), strain (ε), and dislocation density (δ) of the Mn-doped BST ceramics were examined from the recorded XRD patterns using the Scherrer and Williamson–Hall (W–H) models, which showed that the crystallite size increased and the lattice strain and dislocation density decreased with increasing doping concentrations. FTIR results for the pristine sample of BST revealed that the absorption peak at a wavenumber of 470 cm⁻¹ was shifted to 1250 cm⁻¹ for Mn-doped BST concentrations. The Raman results indicated that the number of modes decreased with the increase in the Mn²⁺ concentrations. PL spectra showed an emission band centered at 60–659 nm, indicating redshift behavior. The analysis using XRD, SEM, FTIR, and Raman spectroscopy revealed that the concentration x = 0.20 is appropriate for use in microwave devices and other electro-optical applications.

In the present study, anatase phase titanium dioxide (A-TiO₂)-reinforced polyvinylidene fluoride (PVDF) nanocomposite films are synthesized by the solvent casting method. The electroactive phase, dielectric, and piezoelectric properties are studied for A-TiO₂ nanoparticles at 0.8 wt.%, 1.6 wt.%, 2.4 wt.%, 3.2 wt.%, and 4.0 wt.% content in the PVDF matrix. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy are used to assess the structural properties and the enhancement in the electroactive β phase, respectively. The β phase is found to improve up to 77%. Atomic force microscopy (AFM) shows that the roughness of the films increases with an increase in the amount of reinforcement. The dielectric constant (ε′) and dissipation factor are found to vary with filler weight percentage and frequency. The dielectric constant increases to 24.45 for 2.4 wt.% of A-TiO₂ nanoparticles. The piezo-response increases significantly from 0.6 V to 1.3 V for the nanocomposite in comparison to pure PVDF films. The results of the current study show numerous potential applications in energy-harvesting pressure sensors.

Pristine ZnO and Sm-doped ZnO nanoparticles were synthesized using a wet chemical co-precipitation technique. The morphological and structural characteristics of pristine and Sm-doped ZnO were studied by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. Increases in lattice parameters, interplanar spacing, and volume was observed from the XRD patterns compared to its JCPDS card. Crystallite size, dislocation density, deformation stress, lattice strain, and energy density for both pristine and Sm-ZnO nanoparticles were calculated using Scherrer and Williamson–Hall (W–H) methods. An energy bandgap reduction was observed in the Sm-doped ZnO (E_g ~ 2.7 eV), which played a crucial role in explaining the increased leakage currents in Sm-ZnO. The Sm-doped ZnO nanoparticles exhibited a remnant polarization (P_r ~ 0.163 µC/cm²) and a coercive field (E_c ~ 25.33 kV/cm). Current–voltage (I–V) characteristics show maximum current generated on applying varying voltages (V_max = 40 V, I_max =  ~600 μA). Frequency- and temperature-dependent dielectric studies were conducted to examine the change in the values of the dielectric constant and dielectric loss with the variation in frequency and temperature. The Sm-doped ZnO-based nanogenerator generated an output voltage ~ 400 mV at tapping force of ~ 0.02 kgf, which makes it a prominent candidate for self-powered devices.

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The complex permittivity spectra of binary mixtures (0.0 → 1.0) of n-octanol and N,N-dimethylformamide (DMF) were obtained in the lower microwave radiation region using a vector network analyzer (VNA) at 293.15 K The complex permittivity spectra of n-octanol with DMF and binary mixtures were fitted in a dielectric relaxation model (Havriliak–Negami) to obtain the static dielectric constant (ε₀) and relaxation time (τ). Complex nonlinear least-squares (CNLS) fitting was used to fit the complex dielectric spectra. The nonlinear variation in ε₀ and τ against DMF concentration in binary mixtures of n-octanol + DMF indicated hetero-molecular interaction between participating molecular species. The variation in the dielectric constant and dielectric loss against concentration is discussed in light of their dependence on frequency. The microwave radiation heating parameters including power reflected (p_r), power transmitted (p_t), and penetration depth (d_p) were investigated at general purpose and commercial microwave radiation of 2.45 GHz, respectively.

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