Journal of Materials Science: Materials in Electronics最新文献

The In-48Sn/Cu solder joints were fabricated by transient liquid phase (TLP) bonding, and the morphology and growth kinetics of the interfacial intermetallic compounds (IMC) layer were investigated. The results showed that the thin and flat interfacial IMC Cu₂(In, Sn) layer extended into and spalled off in the solder center region. The grains of the interfacial IMC layer coarsened and transformed from a fine rod-like structure to a coarse hexagonal prism-like structure with prominent facets. Spalled IMC particles hinder the coarsening of the interfacial IMC grains. The growth time coefficient of the interfacial IMC layer ranges from 0.306 to 0.427, and the growth activation energy is about 59.98 kJ/mol. The growth mechanism changes from grain boundary motion at 40–60 °C to diffusion growth at 80–100 °C.

In response to the urgent demand for highly sensitive, flexible, and reliable humidity sensors in fields such as environmental monitoring, industrial control, and biomedicine, a humidity sensor with graphene oxide quantum dots (GOQD) and cellulose nanocrystals (CNC) composites as the humidity-sensitive materials and a flexible polyimide-based interdigitated electrode as the transducer is developed in this study. The experimental results show that the capacitive response of GOQD/CNC composites to humidity is greatly improved with a sensitivity of 1439.6 pF/%RH, which is approximately 3 times higher than that of pure GOQD, and more than 21 times higher than that of pure CNC. This significant enhancement is attributed to the synergistic effect between the GOQDs and the CNC, where the addition of the CNC allows for smaller sized GOQDs to adhere to the surface, which mitigates the aggregation of the GOQDs to a certain extent and increases the contact area of the composite with water molecules, thus increasing the sensitivity of the sensors to changes in humidity considerably. Moreover, the GOQD/CNC-based humidity sensor also exhibits good stability, small hysteresis, rapid response/recovery times, and excellent repeatability. This research provides a new approach for the design of high-performance flexible humidity sensors.

TiO₂/Cu/TiO₂ multilayer films were prepared on quartz glass by magnetron sputtering, and the effects of Cu film thickness on the electrical, optical and electromagnetic shielding performance of TiO₂/Cu/TiO₂ multilayer films were investigated. The results show that with the increase of Cu film thickness from 14 to 34 nm, the square resistance of TiO₂/Cu/TiO₂ multilayer films gradually decreases from 13.1 to 3.29 Ω, and the average visible light transmittance of the multilayer films drops from 80.2% to 66.0%. With the increase of Cu film thicknesses, electromagnetic shielding performance of TiO₂/Cu/TiO₂ multilayer films exhibits an upward trend. The total electromagnetic shielding effectiveness (SE_T) of TiO₂/Cu/TiO₂ multilayer film (30/34/30 nm thick) reaches the maximum, and the SE_T value of the multilayer film exceeds 19 dB.

The effect of CeO₂ sintering aid on the microstructural and electrical properties of CaBi₂Nb₂O₉ ceramics was studied. The addition of CeO₂ facilitates a reduction in the sintering temperature of CaBi₂Nb₂O₉, improve the grain morphology, increase the relative density, and induce the c-axis oriented growth of some grains. The incorporation of some Ce ions into the B-sites of [NbO₆] octahedra results in an increased tetragonal distortion, and therefore significantly affects the electrical properties of the ceramics. The sample with 0.6 wt% CeO₂ exhibits an optimal performance with a large remanent polarization (P_r = 18.5 μC/cm²) and a piezoelectric coefficient (d₃₃ = 20.8 pC/N). The results indicate that adding CeO₂ as a sintering aid is an effective strategy for enhancing the performance of CaBi₂Nb₂O₉ ceramics.

The non-homogeneous photo- Fenton technology has been widely used in the field of water treatment due to its environmental friendliness and non-production of iron sludge. However, the recombination of electron–hole pairs limits the catalytic activity of photo- Fenton materials. In this study, a simple hydrothermal method was designed to prepare Cu-doped ZnFe₂O₄ for the efficient removal of tetracycline The material composition and optical properties of the catalyst were characterized using x-ray diffractio scanning electron microscopy transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy. The results showed that the doping of transition metals was introduced to significantly increase the catalytic activity of the catalyst. At a pollutant concentration of 50 mg L⁻¹, ZnFe₂O₄ doped with 1% Cu degraded 97.9% of tetracycline in 60 min with a degradation rate of 0.0498 min⁻¹, which was 12.8 times higher than that of pure ZnFe₂O₄. O₂⁻ and ·OH were found to be the main reactive oxygen species (ROS) causing the degradation. The photo-Fenton efficiency of Cu/ZnFe₂O₄ is still very efficient after five tetracycline degradations (87.2%), and the crystal structure is stable, indicating good stability and the possibility of recycling in photo-Fenton applications.

In this study, SiGe/Si superlattices films (SLs) with different tiers were epitaxially grown by reduced pressure chemical vapor deposition (RPCVD) on 300 mm Si (001) substrate. Crystal quality of SiGe/Si SLs films (relaxation, surface roughness, interface characteristics and dislocation density) were quantitative evaluated by various characterization methods. A systematic investigation was conducted on the transition process of the SiGe/Si SLs films from full strain to relaxation state with increasing stacking layers. And, the variation trend of dislocation density and surface roughness with increasing stacking layers is studied. Additionally, we examined the changes in crystal quality and dislocation density of these SLs films after thermal annealing (20 min, @700 °C), and all the films exhibit higher strain relaxation by generating more misfit dislocations propagating in-plane. This study provides guidance and reference for the regulation of process parameters and the design of superlattice structure in vertically stacked DRAM.

In thermistor materials, the material constant (B) and resistivity (ρ) of manganese-spinel NTC (Negative Temperature Coefficient) thermistors exhibit a clear correlation: changes in one parameter typically align with changes in the other, with few exceptions. This investigation centers on the system of Ni_0.23Mn_1.49-xFe_0.039+xCo_1.24O₄ (x = 0, 0.2, 0.3, 0.33, 0.39, and 0.45) for which, the traditional solid sintering method was used to adjust the Mn/Fe ratio. This study delves into how these varying Mn/Fe ratios affect the electrical characteristics of the thermistor ceramics. As x increases—indicating higher Fe and lower Mn content—room temperature resistivity (ρ₂₅) gradually rises, while the material constant (B_25/50) declines, halting its decrease at x = 0.45. This trend is linked to a decrease in both carrier mobility and carrier concentration, explaining the inverse relationship between resistivity and material constant. This study offers some insights into regulating material constant and resistivity of NTC thermistors.

Magnesium-sulfur (Mg-S) batteries offer excellent energy density, safety, and a cost-effective energy storage system. Realizing Mg-S batteries requires bypassing significant challenges like electrolyte compatibility with electrophilic sulfur and Mg metal and polysulfide shuttling. The present work probes the role of 2-ethylhexylamine (EHA) in modifying the physiochemical properties of solid polymer electrolytes (SPEs) based on polyvinyl alcohol (PVA), silicon dioxide (SiO₂), and magnesium triflate (MgTIF). The introduction of EHA increases the conductivity to approximately 10⁻⁷ S/cm at room temperature, reduces the magnesium stripping/plating overpotential, and improves the interfacial electrode/electrolyte kinetics; further, the optimum concentration (y = 3000 μl) of PVST__yEHA shows a high ionic transference number (({t}_{{mg}^{2+}}=0.88)) (where PVST is an abbreviation for compound composed of (PVA, SiO₂, MgTIF)), there is minimal overpotential over 100 h. Based on optimum concentration (y = 3000 μl), the Mg-S battery exhibits a high initial discharge-specific capacity in the first cycle up to 1837 mAhg⁻¹, and over six cycles, it maintained a reversible capacity of 376 mAhg⁻¹. The present article attempts to overcome some obstacles that prohibit the realization of Mg-S batteries.

In this study, a Zn-doped iron oxide layer was deposited onto a microscope slide using the magnetron co-sputtering technique with direct current (DC) and radio frequency (RF) sources. We comprehensively characterized the resulting Zn-doped Fe₂O₃ thin layer, employing techniques such as XRD, Raman spectroscopy, UV–VIS spectrophotometry, SEM, EDX, & AFM. XRD examination showed the nanocrystalline structure in the thin layer under investigation. Based on recorded absorption data, the band gap energy value calculation resulted in a value of 2.23 eV for the thin film. Raman spectroscopy identified peaks possessing Raman shifts from 100 to 1400 cm⁻¹. SEM investigation illustrated a consistently uniform thin film surface characteristic throughout the substrate. Additionally, the AFM study disclosed a small RMS roughness value, indicative of an unrough surface for the Zn: Fe₂O₃ thin layer. The Fe₂O₃ thin film doped with Zn employing a 30 W DC voltage demonstrated effective hydrogen sensing capability at 300 °C, achieving notable response and recovery time. This work presents a novel application of Zn-doped Fe₂O₃ thin films as highly sensitive and stable hydrogen sensors, tailored for high-temperature environments. The unique combination of nanocrystalline structure and Zn doping optimizes the material’s electronic properties, enhancing its responsiveness to hydrogen gas. This approach offers a scalable, cost-effective pathway for developing advanced sensor technologies suited to environmental monitoring, industrial safety, and hazardous gas detection, making it a valuable addition to the field of gas-sensing materials.