Silicon最新文献

Building constituents used in the construction industry, peculiarly cement and concrete, generate significant carbon emissions. CO₂ discharges from cement constitute approximately 5–9% of global expelling. Geopolymer is a retainable and eco-friendly innovative constituent developed as an option to Portland cement concrete using waste constituents. Therefore, this examination investigated the life cycle carbon emissions and dielectric properties of geopolymer mortars used to reduce climate change and carbon emissions from building materials. The investigation investigated the carbon emission and electromagnetic wave resistance of obsidian-based silica fume-substituted geopolymer mortars using 12 M NaOH as alkali activator. All these properties were compared with Portland cement mortars. When comparing geopolymer and OPC mortars, it was detected that the CO₂ emissions of geopolymer mortars were very low compared to OPC mortars. In addition, when 28-day values were considered, mechanical strength and CO₂ emissions were evaluated together, and as a result, geopolymers yielded lower kg CO₂-eq/MPa values in the range of 66.45%-73.01% compared to the contents of the mixtures. These values show that geopolymers are more environmentally friendly and high performance building materials than OPC mortars.This study investigated the dielectric and electrical properties of standard and modified mortars for high-frequency applications. Measurements were performed up to 888 h of curing using a Vector Network Analyzer (VNA) to obtain Scattering parameters, complex permittivity, loss tangent, and conductivity. The dielectric constant of mortar in control group decreased from 4.161 to 3.340 in 28 day, and its conductivity fell from 34.226 mS/m to 21.891 mS/m. Modified mixtures began with lower initial values but increased and stabilized above the control's final values. Mix 1 demonstrated superior shielding, showing 0.60 normalized signal attenuation through 30 cm, while the control showed 0.50 attenuation. The results obtained from this study demonstrate that geopolymers are not only sustainable and environmentally friendly materials in general, but also measurably reduce CO₂ emissions by 66.45%–73.01% and provide higher electromagnetic shielding performance with a normalised signal attenuation of 0.60. Therefore, geopolymers offer significant potential for both reducing the carbon footprint and high-performance building applications requiring electromagnetic protection.

In this article, we designed a dense wavelength division multiplexing demultiplexer for C band applications and analyzed it for uniform spectral linewidth. The design is made with single ring cavity, modified overlap cavity, and overlap cavity, and it’s performance parameters are determined using simulations. The primary governing structure consists of a Y-shaped inverted input bus waveguide, a cavity, and a drop waveguide. The coupled mode theory is used to study the transmission and reflection properties at the ports. Plane Wave Expansion Method and Finite Difference Time Domain methods are used to determine Photonic Band Gap and observe normalized transmission of the proposed design for analysis, respectively. The proposed design results in a spectral line width of 0.1 nm (at 12.5 GHz) and 0.2 nm (at 25 GHz), a high-quality factor of 12,000, 100% transmission efficiency, and less crosstalk of -33 dB, which meets ITU DWDM Standards. The footprint of the proposed structure is compact with a dimension of 64 µm². Finally, the proposed demultiplexer design achieves a narrow and uniform spectral linewidth. It supports higher data rates, maximizes spectral efficiency, and reduces interference between adjacent channels. These features are essential for future real-time systems. The proposed demultiplexer design delivers a narrow and uniform spectral linewidth, enabling higher data rates, maximizing spectral efficiency, and minimizing interference between adjacent channels, making it ideal for future real-time communication systems in 6G networks.

Graphical Abstract

The current article goals to synthesize of silicon carbide(SiC)/silicon nitride(Si₃N₄) nanomaterials doped polyvinyl alcohol(PVA) as a promising nanocomposites films to employ in various optoelectronics fields. When compare with other films of nanocomposites, the PVA/SiC/Si₃N₄ films have distinguished optical properties, inexpensive, superior physical and chemical properties make them suitable for many futuristic applications. The morphological, structural, and optical features of PVA/SiC/Si₃N₄ films were examined. The morphological and structural features involved FTIR and optical microscope (OM). The results showed the absorbance of PVA/SiC/Si₃N₄ films is high at (UV-S) Ultraviolet spectra. The PVA absorbance enhanced of 90% at λ = 320 nm(UV-S) while its increase of 95.7% at λ = 800 nm (NIR-S) when the SiC/Si₃N₄ ratio reached of 3.9 wt.%. These results make the PVA/SiC/Si₃N₄ films are important and promising for NIR sensing, UV blocking and other optoelectronics applications. The PVA energy gap reduced from 4.7 eV to 2.8 eV and from 4.2 eV to 1.4 eV when the SiC/Si₃N₄ NPs content reached of 3.9 wt.% for allowed and forbidden transitions, and this performance made them welcomed in numerous optoelectronics and photonics approaches. The refractive index was increased from 2.05 to 2.6 at UV-spectra (λ = 200 nm) with rising the SiC/Si₃N₄ NPs content to 3.9 wt.%. The optical factors: absorption coefficient; extinction coefficient; real and imaginary dielectric constants of PVA were enhanced with increasing SiC/Si₃N₄ NPs content; these results cause to made the PVA/SiC/Si₃N₄ films are appropriate in optical applications. The PVA optical conductivity is improved about 94.3% at λ = 320 nm while the SiC/Si₃N₄ content reached of 3.9 wt.%. These values are appropriate for promising optical applications. Finally, the realized results established the PVA/SiC/Si₃N₄ films can be useful for promising optoelectronics fields.

The aim of this study is to develop a composite coating with high-temperature-resistant electrical insulation properties, designed for application on the surface of metallic copper substrates. This addresses the dual challenges of oxidation resistance and electrical insulation for copper components in high-temperature environments. In this research, an organic polysilazane resin was combined with silicon carbide (SiC) filler to create a protective composite coating on metallic copper surfaces. The parameters for the coating preparation process were systematically optimized. To further improve the interfacial compatibility between the filler and the resin, γ-glycidyl ether oxypropyltrimethoxysilane (KH-560) was employed for the surface modification of SiC. The chemical composition changes in the powder before and after modification were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The microstructural morphology of the coating was examined using scanning electron microscopy (SEM), and various properties of the coating were thoroughly investigated. The results demonstrate that the modification of the powder significantly enhanced the coating's resistance to high temperatures, thereby maintaining its structural integrity after exposure to 500 °C for 2 h and 750 °C for 30 min. The coating exhibited a range of superior properties, including exceptional hydrophobicity, high hardness, and substantial electrical insulation. SEM analysis revealed that the dispersion of the modified powder within the coating was improved, reducing the occurrence of agglomeration and enhancing the compatibility between the resin and the powder. This improvement mitigated issues related to coating cracking and adhesion degradation, thereby enhancing the coating's high-temperature resistance. The polysilazane/SiC composite coating, developed through a silane coupling agent interface modification strategy, successfully achieved a synergistic enhancement of temperature resistance and electromechanical protection properties by optimizing filler dispersion and interfacial bonding.

Solar energy has emerged as a promising alternative to conventional energy sources due to its renewable and environmentally benign nature. Silicon-based solar cells remain at the forefront of photovoltaic technologies, where surface texturing plays a critical role in enhancing light absorption and minimizing optical losses. This study investigates the impact of different chemical etchants, 4 M HF with AgNO₃ (0.006 M and 0.008 M) and KOH (2% and 4%) with 20% IPA on the surface morphology and optical properties of multicrystalline silicon (mc-Si) wafers. Surface analysis revealed that Ag-assisted etching promotes the formation of well-defined pyramidal textures, while KOH-based etching results in smoother, wave-like structures. UV–vis diffuse reflectance spectroscopy confirmed that mc-Si wafers etched with 4 M HF + 0.006 M AgNO₃ exhibited the lowest reflectance and highest optical absorbance. These findings highlight the potential of optimized Ag-assisted chemical etching to improve light-harvesting efficiency, offering a viable pathway for advancing high-performance silicon solar cell technologies.

Purpose

Saline stress limits agricultural production, which is more severe in semiarid regions. The umbu-cajazeira (Spondias sp.) is native to the semiarid region of Brazil. Studies on sources and forms of silicon application in Spondias sp. are unpublished. To evaluate the effect of Si applied through different methods on ecophysiology, biochemistry, osmotic and ionic homeostasis of Umbu-Cajazeira seedlings under salt stress.

Methods

The experiment was conducted in a plant nursery using a completely randomized design with five treatments: [T1 = ECw 0.5 dS m⁻¹ (control); T2 = ECw 3.5 dS m⁻¹ (salt stress); T3 = salt stress + 3.5 g of CaSiO₃ (soil application); T4 = salt stress + 2.2 mL L⁻¹ of K₂SiO₃ (foliar application); and T5 = T3 + T4], with eight replications.

Results

Salt stress negatively affected the growth, gas exchange, and photosynthetic activity of Umbu-Cajazeira seedlings. Si fertilization did not positively affect these traits compared to the salt stress treatment, differing only in the content of chlorophyll a, carotenoids, proline, amino acids, and sodium in leaves. Silicate fertilization was insufficient to mitigate the effects of irrigation water salinity (3.5 dS m¹) on the photosynthetic activity and growth of Umbu-Cajazeira seedlings.

Conclusions

Calcium silicate improves osmotic adjustment, amino acid accumulation, and calcium accumulation and reduces sodium content in the leaves of the Umbu-Cajazeira seedlings under salt stress.

The implementation of multi-valued logic (MVL) systems becomes increasingly difficult as silicon MOSFETs reach their scaling limits due to fixed threshold voltages and worsened short-channel effects. Carbon nanotube field-effect transistors (CNTFETs) present a compelling alternative, exhibiting ballistic charge transport characteristics and chirality-dependent threshold voltage tunability—an essential property for realizing efficient MVL implementations. Comprehensive device characterization using HSPICE demonstrates the superior electrical characteristics of CNTFETs over conventional MOSFETs. The ON current (({I}_{ON})) of the n-type CNTFET is approximately 2.66 times greater than that of its n-type MOSFET counterpart, whereas its OFF current (({I}_{OFF})), exceeds by more than 16.1 times. For the p-type devices, the CNTFET exhibits an ({I}_{ON}) over 2.866 times higher than that of the p-type MOSFET, while its ({I}_{OFF}) exceeds by more than 12.4 times. The Ion/Ioff ratio for n-type and p-type CNTFETs is 42.9 and 36.7 times higher, respectively, compared to their MOSFET counterparts. Utilizing chirality engineering, the CNTFETs are specifically adjusted to implement the ternary logic. This work delves into the chirality engineering of CNTFETs, utilizing (19,0) and (10,0) vectors, to develop an optimized novel high-performance and robust CNTFET-based ternary half adder (THA). The proposed 38-transistor architecture employs a dual-supply voltage scheme and eliminates conventional gates and multiplexers, resulting in a compact 4.6 µm² layout. Simulations using the 32-nm Stanford CNTFET model reveal 13.9% lower power consumption (0.940 µW), 12.4% faster delay (50.165 ps), and 25.4% better power-delay product (0.047 pJ) than the best existing THA design. The design also demonstrates strong resilience to parametric variations, making it a promising solution for low-power, high-speed arithmetic units in energy-constrained nanoelectronics systems.

In this work, a novel triple-layer cap recessed gate Al_0.20Ga_0.80N/GaN HEMT on a 6H-SiC substrate in depletion-mode operation is proposed and investigated for radio frequency and low noise applications. An optimization framework focused on 100 nm to 400 nm gate lengths using the Silvaco TCAD. A triple-layer cap enhances 2DEG density and lowers on-resistance due to the increased conduction band bending. The recessed gate technique enhances threshold voltage, improves electrostatic control, and suppresses short-channel effects. The DC characteristics, such as drain current, transconductance, and threshold voltage, have been investigated for the proposed device. In addition, we have also investigated Radio Frequency parameters, specifically cutoff frequency and maximum frequency. Moreover, the noise parameters investigated for the proposed device include the minimum noise figure and noise resistance. An investigation of the noise parameters has been conducted over the frequency span of 10 to 110 GHz, which covers the frequency range up to the W band as per the IEEE radio frequency standard. The proposed device exhibits improved RF and noise parameters in comparison with state-of-the-art devices. The device models are calibrated against experimental data to validate the simulation models. A process flow has also been proposed for the feasibility of device fabrication.

In order to alleviate the problems of bulk solid waste disposal of iron tailings and electromagnetic wave pollution, a composite iron tailings/silicon carbide nanocomposite foam concrete wave-absorbing material was designed in this study. By replacing the cement matrix with iron tailings (20 wt.%) and using nano-silicon carbide doping to achieve functional modification, the mechanism of iron tailings-nano-silicon carbide synergistic effect on foam concrete mechanical and electrical conductivity was systematically revealed. The experimental results show that when the content of iron tailings reaches 20 wt.%, the average pore size increases from 235 μm to 277 μm, and the improvement of pore connectivity promotes the formation of a conductive network. When the content of nano-silicon carbide is 8 wt.%, the compressive and flexural strength reached a maximum of 2.51 MPa and 1.28 MPa, respectively, which increased 25.5% and 37.63%, respectively, compared with the control group. The composite material exhibits a bimodal absorption characteristic in the X-band and Ku-band, producing reflection loss peaks of -24.50 dB and -19.50 dB at 12.38 GHz and 14.00 GHz, in particular. The valid absorbing bandwidths are 1.67 GHz (10.73–12.4 GHz) and 1.4 GHz (13.31–14.71 GHz).

Sodium dodecyl sulfate (SDS) is a widely used anionic surfactant that poses significant toxicity risks to living organisms. In this study, an environmentally friendly and integrated approach for the determination of SDS in aqueous samples is presented. A novel method was developed by combining magnetic dispersive micro solid-phase extraction utilizing amine-functionalized mesoporous silica magnetic nanocomposites with ion-pair liquid–liquid extraction (MD-μSPE/ILLE), followed by visible spectrophotometric detection. This approach enables effective preconcentration and sensitive detection of SDS in water samples. The synthsized nanocomposite (Fe₃O₄@SiO₂@Kit-6-NH₂) was characterized using XRD, BET, FT-IR, SEM, TEM, and VSM methods. To optimize the SDS extraction, the influence of several experimental factors- namely sample volume, pH, adsorbent mass, contact time, and ionic strength- was systematically evaluated using the Taguchi orthogonal array design (OA₁₆). Analysis of variance revealed that ionic strength (58.24%) was the most influential factor affecting SDS adsorption onto the nanocomposite, followed by adsorbent mass (19.78%), sample volume (12.09%), and contact time (7.58%). The maximum SDS extraction efficiency was attained under optimal conditions with a sample volume of 120 mL, adsorbent dosage of 1.0 g L⁻¹, pH 3, and without salt addition. After adsorption step, the conditions of the SDS desorption were optimized and distilled water was chosen as the best eluent. The proposed MD-µSPE/ILLE method exhibited excellent analytical performance, with a linearity range of 2.0–200.0 µg L⁻¹ (R² = 0.9924), limit of detection of 0.55 µg L⁻¹, enhancement factor of 240.0, and a relative standard deviation (RSD %) of 1.7%. The developed method was successfully applied to preconcentrate and determine SDS in environmental water samples, including tap water and industrial wastewaters from detergent and textile factories yielding satisfactory results.