Journal of Electronic Materials最新文献

This study presents the synthesis and characterization of the metal orthophosphate salt Pb(Sb_0.5Al_0.5)(PO₄)₂. The compound was meticulously prepared via solid-state reactions under ambient air conditions. The crystal structure was determined using Rietveld refinement based on powder X-ray diffraction data, providing detailed information on their atomic arrangements and spatial configurations. Pb(Sb_0.5Al_0.5)(PO₄)₂ adopts a low-yavapaiite structure crystallizing in the monoclinic lattice with space group C2/c and Z = 4; a = 16.605(9) Å; b = 5.128(6) Å; c = 8.073(3) Å; β = 115.17(1)°; V = 631(1) ų. Complementary Raman and infrared spectroscopy techniques allowed us to study in more detail the structural and bonding properties of the crystalline solid. In addition, the morphology was studied, and the chemical composition was confirmed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The material's optical bandgap was estimated using ultraviolet–visible (UV–Vis) spectroscopy, and the result was roughly 3.8 eV. The insulating nature of a material cannot be verified by optical observation alone, although the wide bandgap increases the likelihood of such an occurrence. Measuring electrical conductivity is necessary for certain verification of an insulating nature. This study also presents a comprehensive study of the dielectric and electrical conductivity properties of this new material with mixed Sb⁵⁺ and Al³⁺ ions in the octahedral sites of the yavapaiite structure which exhibits very high electrical resistivity over a wide range of frequencies and temperatures. The study uses an approach combining the analysis of permittivity, impedance, complex modulus, and alternating current (AC) conductivity curves, which is very useful for understanding the electrical conduction and relaxation mechanisms in this type of material.

Nanographene immobilized by transition metals such as Cu and Ni has been synthesized and characterized using Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and ultraviolet (UV)–visible spectroscopy techniques. The particles were rod-shaped, measuring 90–100 nm in diameter. SEM data revealed the stalking together of exfoliated graphene oxide. Reduced graphene oxide immobilized by transition metals (Cu and Ni) showed surface plasmon effect. The porosity of the surface revealed that the surface plasmons were localized and dominated by the collective oscillation of electrons in the valence band of the metal. The three-dimensional reduced graphene oxide sheets resembled a loose sponge-like structure. Transmission electron microscopy (TEM) images revealed rod-shaped metal particles immobilized on the RGO surface when exposed to a diffracted electron beam. The size of RGO was found to be less than 100 nm, while the size of GO was more than 100 nm. The band gap energy of RGO, RGO-Cu, and RGO-Ni was 1.35 eV, 0.46 eV, and 1.26 eV, respectively. The primary 2θ peak for GO was a broad peak centered at around 11–12°, corresponding to the (001) plane, whereas RGO exhibited two prominent 2θ peaks at 25° and 43°. Copper-doped RGO displayed five peaks at 19°, 25°, 43°, 50°, and 74°, while the 2θ peaks of nickel-doped RGO were observed at 25°, 43°, 51°, and 52°. The synthesized compounds were tested for their ability to retain dissolved oxygen, revealing that RGO-Cu traps bacteria to a greater extent, with the dissolved oxygen (DO) level in water being maintained even after 5 days. RGO-Ni works as a potent absorber of other pollutants in water to release more DO than normal bacteria, using oxygen to trap the harmful bacteria and reducing other metal oxides into neutral forms.

Graphical Abstract

A structure representing the formation of graphene-immobilized transition metal (Cu²⁺ and Ni²⁺) by the reverse micelle method: Transition metals are immobilized in the micelle, and subsequently, graphene sheets interact with immobilized transition metal ions by facilitating their distribution on its surface.

Supercapacitors have garnered significant attention among today’s researchers due to their high capacitance. For supercapacitors, two-dimensional materials like graphene and its derivatives (graphene oxide [GO] and reduced graphene oxide [rGO]) and their composites with transition metal oxides are of great interest. In this study, one of the transition metal oxides, Fe₂O₃, was synthesized using a modified sol–gel method, and synthesized GO was used. Three composites with different concentrations of GO (10%, 20% and 30%) were formed via the ball milling method. X-ray diffraction (XRD) confirmed the rhombohedral structure of the prepared samples, with (104) as the highest peak. A carbon (103) peak also appeared in the composite samples, which confirmed the successful formation of the composite materials. The surface morphology was studied by scanning electron microscopy (SEM). Reduced agglomeration was seen in SEM images with increasing concentration of GO. Frequency-dependent dielectric and electrical properties were determined using a precision component analyzer in a range of 100 Hz to 3 MHz. The electrochemical performance was investigated using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). Fe₂O₃ with 0% GO showed the highest specific capacitance of 152 F/g at 10 mV/s and discharge time of 119 s at 0.5 A/g, which decreased with the increasing concentration of GO, due to oxygen-containing functional groups present in GO.

This study presents a surface plasmon resonance (SPR) biosensor design that integrates graphene-coated resonators with multi-metallic layers (Au, Ag, Cu, Al) for an enhanced breast cancer biomarker detection in the terahertz frequency range. Computational modelling using COMSOL Multiphysics software demonstrates exceptional performance metrics, including sensitivity’s values reaching 500 GHz/RIU, figure-of-merit up to 5.263 RIU⁻¹, and detection accuracy of 10.526 across the operational frequency range of 0.1–0.6 THz. In addition, the biosensor’s performance is further optimized through locally weighted linear regression (LWLR) machine learning algorithms, achieving prediction accuracies with R² values ranging from 86% to 93% for various operational parameters including graphene chemical potential (0.1–0.9 eV) and incident angles (0–80°). The electromagnetic field analysis reveals maximum energy confinement at 0.25 THz, with reflectance values stabilizing between 72% and 76% under optimal conditions. This innovative approach addresses critical limitations of conventional mammography and invasive biopsy procedures, offering a noninvasive, highly sensitive platform for detecting breast cancer biomarkers (CA 15-3, HER2, circulating tumor DNA) from picomolar to femtomolar concentrations, potentially revolutionizing early-stage breast cancer screening protocols.

Two-dimensional transition metal carbides (MXenes) have shown great promise for developing flexible polymer nanocomposites with high dielectric constant. A critical challenge lies in balancing high dielectric constant with low dielectric loss, which is governed by the electrical conductivity of the nanofiller. This study investigates two-dimensional Nb₂CT_x MXene as a promising low-conductivity filler for achieving this balance. Nanocomposites of poly(vinylidene fluoride) (PVDF) containing 5–30 wt.% Nb₂CT_x were prepared and characterized by x-ray diffraction, scanning electron microscopy, and simultaneous thermal analysis (TGA-DSC). The dielectric properties were studied by impedance spectroscopy over a temperature range from −50°C to 130°C. The nanocomposite with 30 wt.% Nb₂CT_x exhibited a high dielectric constant (ε’ ≈94) with a concurrently low dielectric loss tangent (tan δ ≈0.2) at 10 kHz. While the dielectric constant values were comparable to those of nanocomposites with previously studied MXene fillers, such as Ti₃C₂T_x or V₂CT_x, the dielectric losses were significantly lower, highlighting the advantage of the two-dimensional Nb₂CT_x filler. The temperature-dependent dielectric response was primarily dominated by the PVDF matrix, regardless of filler concentration. These findings underscore the potential of two-dimensional Nb₂CT_x MXene for designing advanced flexible dielectric films with tailored dielectric properties.

Direct ink writing (DIW) is an additive manufacturing technique that enables the deposition of conductive liquid materials for electronic applications. However, achieving continuous micron-scale tracks with consistent track width and electrical properties poses a critical challenge essential for the reliability of electrical circuits. This study examines the deposition of copper-based conductive ink utilizing an in-house-developed DIW setup. The objective is to optimize process parameters to enhance track width (TW) accuracy and sheet resistance (SR). The process parameters, including stand-off distance, extrusion multiplier, nozzle diameter, and print speed, were investigated for their effect on tracks and electrical performance using response surface methodology (RSM). Multi-objective optimization was utilized to define quantitative relationships between process variables and performance metrics. The findings indicate that linear, quadratic, and interaction terms significantly affect TW and SR. The predicted TW and SR values derived from Pareto-optimized parameters strongly correlate with experimental results, indicating a high level of predictive accuracy. A functional circuit was fabricated as a case study to demonstrate the practical applicability of the deposited tracks, integrating various electronic components for DC voltage regulation. Results highlight the significance of optimizing process parameters in producing high-quality conductive tracks using DIW for advanced electronic applications.

The physical properties of perovskite manganite with hexagonal structure is of interest for its additional functionalities. However, unlike LaMnO₃ with orthorhombic and rhombohedral phases, which has been extensively studied, LaMnO₃ with hexagonal structure is not typically investigated. This work systematically investigates the structure, magnetism, and transport properties of hexagonal LaMnO₃. Magnetization measurements of the hexagonal LaMnO₃ reveal a magnetic transition with a Curie temperature (T_C) of 245 K, distinct from the Néel temperature (T_N) ≈140 K of orthorhombic LaMnO₃. Resistivity measurements indicate a metal-insulator transition near T_C. Under a 6 T field, the sample exhibits a negative magnetoresistance (−MR) of 56.11% at 242 K and maintained a significant MR effect over a wide temperature range, which was attributed to the synergistic effects of spin-polarized tunneling, sample inhomogeneity, Jahn–Teller distortion, and double exchange interaction. The electrical transport behavior at high temperatures follows the variable range hopping model. The significant MR effect over a wide temperature range appears in the hexagonal LaMnO₃, highlighting the potential for spintronics applications.

This study provides a detailed analysis of the electronic and optical characteristics of 2D TiC-based MXenes using complex density functional theory (DFT) computational techniques. The study examines the impact of surface functionalization on the performance of significant transition metal MXenes, specifically Ti₃C₂, V₂C, and Nb₂C, in energy storage applications. The results show that these materials retain metallic properties crucial for optimal electrical conductivity. Ti₃C₂, V₂C, and Nb₂C reveal significant optical activity, as evidenced by their unique refractive indices and absorption coefficients, with plasma edge values observed at 0.1 eV, 0.5 eV, and 0.3 eV, respectively. Ti₃C₂ functions with an indirect bandgap, which makes it especially well-suited for infrared photodetection and thermal imaging, according to the investigation of band structures. V₂C and Nb₂C indicate potential for supercapacitor applications, attributed to their rapid charge transfer capabilities facilitated by d-orbitals above the Fermi level. Our analysis emphasizes the materials’ applicability for solar cell technology by highlighting the critical roles of the anisotropy of the dielectric constant and the overlap between the transmittance and absorption bands. These results highlight the innovative potential of TiC-based MXenes in optoelectronic devices and next-generation energy storage solutions, opening the door for future uses in various technological fields, such as sensors, semiconductor manufacturing, and renewable energy harvesting.

Graphical Abstract

Based on atomistic calculation of electronic transport, we propose a new recipe to enhance the thermoelectric power factor by utilizing the exotic transport of Weyl point fermions. The Weyl semimetal SrSi₂ is used as an example to illustrate the underlying correlation. We find that (i) the twofold degenerate Weyl point helps to produce the peak Seebeck coefficient, resulting in a peak and enhanced power factor, (ii) the eliminated degeneracy of physical spin under spin–orbit coupling significantly reduces the Seebeck coefficient, and (iii) if the Weyl point is opened with a significant gap, both the Seebeck coefficient and electrical conductance are decreased, which in turn indicates a direct correlation between the presence of Weyl points and improved thermoelectric performance.

With the extensive application of third-generation semiconductor devices in the drive motors of new energy vehicles, soft magnetic composites (SMCs) have attracted much attention owing to their excellent direct current (DC) bias characteristics and high saturation magnetic induction intensity. However, SMCs still face the “permeability-loss” trade-off dilemma in high-frequency and high-power density applications. In this study, an environmentally friendly acetic acid passivation strategy was innovatively adopted to in situ generate a uniform and continuous Al₂O₃ insulating layer on the surface of flaky FeSiAl powders. By systematically regulating the acetic acid passivation time (20–100 min), FeSiAl–Al₂O₃ SMCs with different Al₂O₃ coating characteristics were prepared, and their magnetic properties were characterized in detail. The experimental results show that when the acetic acid passivation time is 60 min, the FeSiAl–Al₂O₃ SMCs achieve a synergistic breakthrough in ultra-high permeability (97.6 @2 MHz), ultra-low power loss (93.6 kW/m³ @50 mT/100 kHz), and strong DC bias stability (>70%71.98 Oe) simultaneously, showing excellent comprehensive magnetic properties. This study provides new ideas and technical support for the development of high-performance and green-manufactured SMCs, and is expected to achieve more efficient electromagnetic energy conversion in high-frequency and high-power density application scenarios.