Journal of Electronic Materials最新文献

This study investigates the structural, vibrational, and magnetic properties of Ni_1–xCd_xFe₂O₄ spinel ferrites, synthesized via the citric-assisted solution combustion method, with Cd doping ranging from 0.0 to 1.0 (in increments of 0.2). A comprehensive characterization approach, including powder x-ray diffraction (XRD), scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, vibrating sample magnetometry (VSM), electron paramagnetic resonance (EPR), and ⁵⁷Fe internal field nuclear magnetic resonance (IFNMR) at 77 K, was used to analyze the samples. XRD analysis revealed that the crystallite size of the NCF samples increased with Cd content from NCF 2 to NCF 8, with no significant change observed for pure nickel ferrite (NCF 0) and cadmium ferrite (NCF 10). Structural defect parameters, such as the dislocation density and strain, decreased with increasing Cd at the A-site. The FTIR and Raman spectra showed a decrease in the wave number and force constant at the B-site as the cadmium content at the A-site increased, with Raman peaks related to the B-site vanishing in NCF 6 to NCF 10, indicating the presence of NiO₄/FeO₄ tetrahedra. Magnetic characterization by VSM and EPR indicates that a higher cadmium content (NCF 8 and NCF 10) results in nonmagnetic behavior, characterized by minimal magnetic saturation and absence of microwave absorption. ⁵⁷Fe IFNMR revealed a marked reduction in A-site occupancy and a corresponding increase in B-site occupancy as Cd doping progressed from NCF 0 to NCF 6, suggesting a shift of Ni ions to the B-site due to the nonmagnetic Cd doping at the A-site. No NMR signals were observed for NCF 8 and NCF 10, further confirming the nonmagnetic nature of these samples. The XRD, VSM, FTIR, Raman, and IFNMR results converged, demonstrating a clear link between Cd doping, site occupancy, structural evolution, and magnetic properties, highlighting the potential for tailoring the material properties for specific applications.

The reliability of the die attach structure in silicon carbide (SiC)-based insulated-gate bipolar transistors (IGBTs) is critical for high-performance power electronics applications, as thermal cycling and mechanical stresses can induce premature failure. In this work, an analytical model was developed to evaluate stress and strain distributions within IGBT modules under cyclic thermal loading conditions. Leveraging established geometric dimensions and material properties of the die, solder, and substrate, the model directly computes the assembly stiffness (K) and the imposed strain (D), thereby eliminating the need for iterative finite element (FE) simulations and significantly reducing computational time. The accuracy of the proposed model was validated through FE simulation. Subsequently, die attach structures were fabricated using lead-rich solder and sintered copper with varying thickness configurations. Experimental validation was conducted to corroborate the model’s predictive rationality. Meanwhile, the model proposed in this manuscript was compared with other analytical models and evaluated against alternative lifetime prediction approaches. These results provide critical insights into optimizing die attach design and material selection to enhance the reliability and lifespan of power electronics modules under harsh operating conditions.

Photocatalysis has emerged as a pioneering green technology to address the wide range of challenges related to decomposition of harmful organic dyes in wastewater, yielding less toxic byproducts. In our work, the photocatalytic properties of tin selenide (SnSe) thin films were studied using methylene blue as a representative dye. SnSe thin films were grown using radio-frequency (RF) magnetron sputtering. To analyze the structural and physical characteristics of the thin films, several techniques were utilized, including x-ray diffraction for phase and crystallinity study, field-emission scanning electron microscopy and energy-dispersive x-ray analysis (EDAX) for surface morphology and elemental composition, ultraviolet (UV)–visible spectroscopy for optical analysis, and Raman spectroscopy to investigate the vibrational modes of the SnSe thin films. Photocatalytic activity was assessed via UV–visible absorption spectroscopy in the range 400–800 nm by measuring methylene blue photodegradation under sunlight irradiation. The results demonstrate that SnSe thin films exhibit excellent photocatalytic efficiency, with 96.1% and 96.5% photodegradation achieved in 715 min of light exposure for films with thickness of 38 nm and 210 nm, respectively. The rate constants for the photocatalytic reaction were determined to be 0.00477 min⁻¹ and 0.00486 min⁻¹ for films with thickness of 38 nm and 210 nm, respectively. This study highlights the potential of tin selenide thin films as an excellent photocatalyst for wastewater treatment problems.

To address the need for sensitive, low-frequency environmental monitoring, a dual-mode thin-film capacitive sensor for humidity and pressure detection was developed. The device employs chromium/gold (Cr/Au, 30 nm/100 nm) interdigitated electrodes on quartz, functionalized with a para-nitroaniline (p-NA) active layer via spin coating (5 wt% in ethanol) and annealing at 60°C. Capacitance measurements in a custom humidity chamber (100 Hz–10 kHz) demonstrate high humidity sensitivity (5.6 nF/%RH at 100 Hz) with a fast 9 s response, minimal hysteresis (4.09 nF), and excellent reversibility. Under applied pressure (30–90 kPa), the sensor achieves maximum sensitivity of 600 F/kPa at 100 Hz, which decreases at higher frequencies. The strong low-frequency response is attributed to enhanced dipolar and ionic polarization facilitated by the electron-withdrawing (–NO₂) and electron-donating (–NH₂) functional groups of p-NA. Furthermore, the device maintains stable performance over extended cycling, confirming its reliability for long-term operation. These results demonstrate a robust, cost-effective dual-mode sensor with high stability and swift responsiveness, suitable for reliable ambient humidity and pressure monitoring.

The evaluation of the ion diffusion mechanism and magnetic properties of ecofriendly strontium-copper ferrite-based nanomaterials for hydroelectric cells via the green synthesis technique using plant-extract-facilitation is an innovative nanotechnology approach for the ecologically sustainable and economical manufacturing of nanoparticles. The coprecipitation synthesis of strontium and copper ferrite nanomaterials was successfully carried out using green plant extracts i.e., aloe vera, ensuring environmental sustainability. x-ray diffraction analysis verified the establishment of the pure crystalline phase, and the nanometer-scale structural parameters and crystallite size were determined. Field emission scanning electron microscope (FESEM) images confirm more or less spherical particles for CuFe₂O₄, with a size of 79 nm, whereas that of 7.5% Sr:CuFe₂O₄ is 99 nm. Fourier transform infrared (FTIR) spectroscopy revealed a monophase spinel crystal structure. The dielectric behavior exhibited an exponential decline in both the constant and loss factor as frequency increased, whereas the ion diffusion mechanism confirms better-quality dielectric, impedance properties of nanomaterials. The saturation value was determined through magnetic measurements using a vibrating sample magnetometer (VSM) instrument at ambient temperature. The CuFe₂O₄ nanomaterial exhibited a greater performance with a current of 3.7 mA and 7.5%Sr:CuFe₂O₄ nanomaterial showed an extreme of 1.4 mA, highlighting the pathways for ion diffusion. These results establish strontium and copper-ferrite nanomaterials as advantageous for microelectronic and hydropower applications.

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The development of spintronic and magnonic technologies hinges on materials capable of supporting pure spin currents with minimal energy loss. Among various candidates, ferrimagnetic insulators are uniquely suited for this purpose, offering high magnetic coherence and low dissipation. This review focuses on the physical mechanisms and material phenomena underlying spin transport in hybrid structures, particularly those incorporating yttrium iron garnet (YIG). Central spintronic effects, including spin Seebeck and spin Hall effects, spin pumping, magnetic proximity effects, and spin, orbit, or spin transfer torques, are examined in detail, emphasizing their dependence on interfacial structure, chemical composition, and magnetic hybridization. Advances in nanofabrication of high-quality YIG thin films and the engineering of spin–orbit-active interfaces are discussed in the context of energy-efficient spin logic and coherent spin wave-based devices. By bridging fundamental insights with applied developments, this review aims to outline the state of the art and identify key challenges and opportunities in insulating spintronics.

Graphical Abstract

Rotary motion energy harvesting technology has garnered significant attention for its potential to continuously power low-power electronic devices, such as wireless sensors. To address the limitation of effective energy harvesting occurring only at the resonant frequency, this study proposes an innovative magnetostrictive rotational motion energy harvester based on a shared pre-magnetized magnetic field. By magnetizing the mass block at the tip of the cantilever beam in the same direction as the pre-magnetized magnetic field, the structure achieves, for the first time, an upregulation of the system’ resonant frequency through the nonlinear magnetic force generated between them. To elucidate the influence mechanism of the nonlinear magnetic force on system performance, magnetic force distribution along various directions of the cantilever beam during motion is obtained through magnetic field simulations and curve fitting, followed by numerical simulations and comparative analysis of the harvester’s output characteristics. Results indicate that the introduction of a nonlinear magnetic force not only effectively increases the system’s resonant frequency but also mitigates the super-resonance suppression phenomenon and enhances energy output efficiency. Additionally, this study systematically investigates the effect of the number of coil turns on output performance. Experimental results show that the innovative system can expand the frequency response bandwidth by 1.28–1.83 times. Additionally, the output performance improves by up to 11.9 times when the number of coil turns is optimized to 1000. These results validate the accuracy of the theoretical model and demonstrate the potential of the proposed structure for practical applications in rotary motion.

The increasing global demand for clean, portable, and sustainable energy sources is propelled by the growth of wearable electronics, Internet of Things (IoT) devices, and environmental monitoring, which has led to increased attention towards technologies that are capable of harvesting low-frequency mechanical energy. Triboelectric nanogenerators (TENGs) have emerged as a promising solution owing to their lightweight design, low cost, and high energy conversion efficiency. This review is motivated by the urgent need to advance TENG technology from lab-scale concepts to real-world applications. We provide a comprehensive yet easy-to-understand overview of the fundamental working principles, operational modes, and material classifications of TENGs. We focus on nanomaterials, such as graphene, carbon nanotubes, and metal-organic frameworks, that improve performance and permit scaling up. The review also addresses practical challenges, including material degradation, fabrication bottlenecks, and integration with existing systems. In addition, sustainable design pathways using biodegradable and recyclable materials are discussed to support green energy solutions. Researchers, engineers, and product developers in flexible electronics, self-powered sensing, and sustainable device design will find this review valuable for guiding innovation and commercialization efforts. This work outlines a forward-looking roadmap for developing next-generation TENG-based energy systems by bridging scientific advances with practical deployment.

The structural and performance evolution of MS₂ (M = Mo, W, V) materials under lithium insertion are investigated via first-principles calculations. Our study reveals a significant anisotropic expansion along the c-axis during lithium intercalation, while lithium substitution induces localized strain and charge redistribution. Mechanical property analysis shows reductions in elastic constants and Young’s modulus, with 2H-phase materials exhibiting superior resilience under the substitution. Electronically, lithium incorporation modulates the density of states near the Fermi level, enhancing the metallicity and conductivity in substituted 2H-WS₂ and 1T-MoS₂. These findings provide insights into the structural and electronic mechanisms governing the performance of MS₂ materials as lithium-ion battery anode candidates, offering pathways for future material optimization and design.