Search Results (24,791)

In this study, the diffusion barrier performance of TiN and SiC layers was investigated in Si/TiN/Cu, Si/TiN/SiC/Cu, and Si/SiC/TiN/Cu multilayer structures to address copper diffusion issues at silicon interfaces in microelectronics. Samples were annealed in argon at 500–800 °C for 30 min, and diffusion behavior was analyzed using X-ray diffraction (XRD) and sheet resistance measurements. The Cu₃Si phase formed at 600 °C in the Si/TiN/Cu system, while no Cu₃Si appeared in the Si/SiC/TiN/Cu system up to 700 °C, indicating improved stability. Complete copper diffusion occurred in all systems at 800 °C. Sheet resistance measurements corroborated the XRD findings, demonstrating that multilayer structures incorporating TiN and SiC significantly enhance thermal stability and suppress copper diffusion. Comparison of Si/SiC/TiN/Cu and Si/TiN/SiC/Cu stacks annealed at 700 °C revealed that the stability of TiN depends on layer sequence, with SiC effectively blocking Cu migration into TiN when placed adjacent to Cu. Structural and morphological properties of TiN films were also examined, confirming their suitability as diffusion barriers. Additionally, the feasibility of forming a low-resistivity TiSi₂ layer through a single annealing step to create a TiSi₂/TiN system was explored, highlighting potential applications in advanced device integration. Full article

In this study, in situ P-doping of Ge-based layers has been studied and compared with implanted layer profiles acting as absorbent top layer in PIN photodetectors. Several structures containing multilayers of n⁺-Ge/i-Ge, n⁺-GeSi/i-Ge, and n⁺-Ge/i-GeSi, were designed to regulate dopant out-diffusion and interface quality. The purpose of this study is to make an optimized n-type doping layer for PIN photodetectors with low dark current, high responsivity, and high quantum efficiency operating in short wavelength infrared (SWIR) region. The Ge-based structure on Si substrate was transferred to oxidized Si substrate and was finally back-etched from Si to form Ge-on-insulator (GOI) substrate. Comprehensive characterization using high-resolution X-ray diffraction (HR-XRD), secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and photoluminescence (PL) have been applied at the first stage of our work. The initial Ge layer contains tensile strain of 0.15–0.17%. PL measurements further indicate a redshift of the Γ-LH transition and carrier-concentration-induced quenching at high doping levels, highlighting the competing effects of band filling and non-radiative recombination in heavily n-doped Ge structures. To circumvent this fundamental trade-off, we devised a decoupled device strategy in which the active absorption region employs an intrinsic Ge/GeSi nanoscale multilayer structure to preserve crystal and interface quality. Although, the epitaxial growth parameters were on the optimized conditions, still out-diffusion (in form of segregation and auto-doping) of P could not be impeded. Our final n-type layer in PIN structure was formed by implantation. This approach yields high-performance photodetectors with a peak responsivity of 0.99 A/W at 1550 nm, a corresponding external quantum efficiency of 79%, and low specific contact resistivities of 2.66 × 10⁻⁶ Ω·cm² (n-type) and 1.38 × 10⁻⁸ Ω·cm² (p-type). This work demonstrates that the strategic combination of multilayer/interface engineering and ion-implantation-based doping is a highly effective strategy for tailoring the optoelectronic properties of Ge-based nanomaterials for high-performance SWIR photodetection. Full article

This study aims to enhance and develop the properties of materials used as supercapacitors. The synthesis of graphene oxide (GO) was achieved via a modified Hummer’s method, whereas the fabrication of polyaniline (PANI)/GO nanocomposites was conducted utilizing an in situ chemical polymerization technique. Subsequently, the PANI/GO layered films were deposited on fluorine-doped tin oxide (FTO) glass for supercapacitor applications. The materials were analyzed using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and cyclic voltammetry (CV). The experimental results demonstrated that a reaction time of 30 min, along with a weight ratio of aniline (ANI) monomer to GO of 1:1.5, yielded an optimal specific capacitance of 13.30 F/g. The robust electrochemical performance of the PANI/GO electrode may stem from the increased active sites for PANI deposition, attributable to the large surface areas of GO. Full article

Despite the promising exploration potential of the tight bioclastic limestone in the Carboniferous Shiqiantan Formation (Shiqiantan Sag, Junggar Basin), its reservoir characteristics remain poorly constrained. In particular, the macro and microscopic features and the key factors controlling reservoir development are still not well understood. We combined core observation, cast thin-section analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), high-pressure mercury intrusion, nitrogen adsorption, and nuclear magnetic resonance (NMR) to systematically characterize the Carboniferous bioclastic limestone reservoirs and identify the factors controlling their development in the Shiqiantan Sag. This study develops a multi-scale quantitative framework that integrates mercury intrusion–withdrawal behavior, nitrogen adsorption, and NMR T₂ spectra to constrain pore connectivity and the contribution of microfractures in tight carbonate reservoirs, providing a transferable approach for reservoir evaluation beyond the study area. The results categorize three rock microfacies in the study area: Bioclastic micrite, Micritic bioclastic limestone, and Sparry Bioclastic Limestone. The reservoir space is predominantly composed of secondary pores, including intragranular dissolution pores, intercrystalline clay pores, and microfractures. The pore structures exhibit a marked contrast across the lithofacies: the sparry bioclastic limestone develops the most optimal pore-fracture composite system, The pore structures exhibit a marked contrast across the lithofacies, directly correlating with hydrocarbon accumulation. Specifically, the sparry bioclastic limestone develops a pore-fracture composite system characterized by 25–100 nm pore throats, corresponding to the primary oil-bearing intervals observed in drilling. In contrast, the bioclastic micrite limestone and micritic bioclastic limestone, despite exhibiting localized nanoscale pores, lack effective connectivity (pore throats < 25 nm) and predominantly act as tight, dry layers with poor or no oil and gas shows, which endow them with the anomalous characteristic of relatively low porosity yet high permeability. This study reveals an integrated control on the development of tight bioclastic limestone reservoirs, in which sedimentary microenvironment and paleogeomorphology jointly determine the initial reservoir framework, while subsequent structural fractures and associated diagenetic dissolution play a critical role in modifying pore structures and enhancing reservoir quality. Sedimentary microfacies distribution, controlled by paleogeomorphologic variations, dictated the initial reservoir fabric. Subsequently, fracture systems generated by tectonic uplift, coupled with dissolution from meteoric freshwater leaching and organic acids, facilitated the development of secondary pores. Ultimately, the resulting optimization of the pore structure governs the final reservoir quality. The sparry bioclastic limestone is identified as the most promising exploration target in the study area. Its favorable reservoir quality is mainly attributed to its development on palaeogeomorphic and structural highs, where enhanced hydrodynamic energy and subsequent fracture-related dissolution significantly improved pore connectivity. These high-quality reservoirs are widely developed on gentle slope profiles and similar high-quality reservoirs may also locally occur at isolated palaeogeomorphic highs within steep-slope settings, as demonstrated by individual wells. Full article

The negative impacts caused by synthetic herbicides have necessitated research on environment-friendly and sustainable alternatives. In this study, a novel botanical nanoherbicide was developed through green synthesis of silver nanoparticles (Ag NPs) assisted by aqueous extract of Brucea javanica (BJ) residue. The BJ-Ag NPs were characterized using ultraviolet–visible (UV–Vis) absorption spectroscopy, dynamic light scattering (DLS), zeta potential analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM) attached with energy dispersive X-ray spectroscopy (EDX). TEM images indicated that the BJ-Ag NPs were spherical with an average particle size of 12.75 nm. Meanwhile, the herbicidal activity against two paddy weeds (Echinochloa crusgalli and Bidens pilosa L.) and phytotoxicity to rice (Oryza sativa L.) were evaluated using the Petri dish method. Compared to the BJ residue extract, the BJ-Ag NPs exhibited enhanced inhibitory activity on the seed germination and seedling growth of two target weeds, while showing alleviated phytotoxicity and partially restored seedling vigor in rice. Obviously, positive impacts on both the weed and crop were obtained after synthesizing Ag NPs using the BJ residue extract. The results in this study demonstrated the potential of the BJ-Ag NPs as a sustainable, crop-friendly nanoherbicide for weed management in paddy fields. Full article

High-entropy alloys (HEAs) provide a broad compositional space for tuning phase stability and surface durability. CoCrFeNiMn_x (x = 0.5, 1.0, 1.5, and 2.0) alloys were fabricated by vacuum arc melting and characterized by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS), microhardness testing, electrochemical testing in 3.5 wt.% NaCl, and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations and first-principles molecular dynamics were further employed to analyze the Mn-dependent electronic structure and oxygen–metal bonding. The XRD results indicate a transition from a single FCC solid solution at x ≤ 1.0 to an FCC + BCC constitution at x ≥ 1.5. With increasing Mn, microstructures evolve from coarse dendrites toward higher fractions of equiaxed grains. Hardness decreases from 163.6 HV (x = 0.5) to 125.1 HV (x = 1.0) and then increases to 162.6 HV (x = 2.0), indicating competing solid-solution and phase/segregation effects. Electrochemical measurements show enhanced corrosion resistance with Mn addition; the x = 2.0 alloy exhibits the lowest fitted corrosion current density (icorr = 0.3482 × 10⁻⁶ μA·cm⁻²) and the most stable passivation response. XPS reveals passive films dominated by Fe₂O₃ together with Mn³⁺ oxides, whose synergistic formation promotes a denser barrier layer. DFT predicts a monotonic decrease in Fermi level and a narrowed conduction band range as Mn increases, consistent with reduced electron transfer activity during anodic dissolution. Interfacial simulations show that O preferentially bonds with Cr and Mn, while Ni–O bonds have the lowest estimated rupture barrier, rationalizing a tendency toward localized corrosion at Ni-associated sites. Full article

The aqueous sol–gel preparation technique was successfully employed for synthesizing a homogeneous La–Ti–Mo–O tartrate gel precursor, and thermal treatment at 1000 °C promoted the formation of nanocrystalline complex La_2−xTi_xMo₂O_9+x/2 ceramic. X-ray diffraction analysis revealed a consistent influence of increasing the degree of titanium substitution on the formation of the La₂Mo₂O₃ and La₂MoO₆ impurity phases within the crystalline mixture. Meanwhile, the stability of the high-temperature cubic β-La₂Mo₂O₉ phase in the La_2−xTi_xMo₂O_9+x/2 system at room temperature highlighted the distinct influence of titanium content from structural and thermodynamic perspectives. However, the Raman spectroscopy analysis showed no distinct variations in the spectra of La_2−xTi_xMo₂O_9+x/2 samples, suggesting a substantial effect of titanium on the phase transition behavior between the low-temperature monoclinic α-La₂Mo₂O₉ and the high-temperature cubic β-La₂Mo₂O₉ phases. Full article

Background: The eco-friendly synthesis of silver nanoparticles (AgNPs) utilizing medicinal flora presents a viable strategy for the development of multifunctional agents exhibiting antimicrobial, antioxidant, anti-inflammatory, and anticancer properties. This investigation aims to elucidate the phytochemical composition of Calotropis gigantea and its contribution to the synthesis of CG-AgNPs that demonstrate efficacy against Helicobacter pylori and gastric cancer cell lines. Methods: The aqueous plant leaf extract of C. gigantea underwent comprehensive analysis via gas chromatography-mass spectrometry (GC-MS), identifying a total of 25 bioactive constituents, including oleic and oxalic acid derivatives. The fabrication and analysis of silver nanoparticles (AgNPs) were performed utilizing methodologies including ultraviolet-visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), and assessments of zeta potential. Antibacterial efficacy was evaluated through methods including agar well diffusion, time-kill kinetics, and biofilm assays. The cytotoxic impact on AGS gastric cancer cells was investigated using MTT assays, DAPI staining, and acridine orange/ethidium bromide (AO/EtBr) staining techniques. The assessment of antioxidant potential was performed utilizing DPPH and ABTS assays. The anti-inflammatory properties were analyzed through protein denaturation and membrane stabilization tests. Results: CG-AgNPs exhibited a spherical morphology (11–17 nm) with commendable stability, denoted by using zeta potential analysis measurement of −30.2 mV. The antibacterial activity showed a significant inhibition zone of 16.00 ± 0.17 mm at a concentration of 50 µg/mL against H. pylori, in addition to notable biofilm disruption. The viability of AGS cells was reduced by 61% at a concentration of 100 micrograms per milliliter, with apoptosis being confirmed through relevant assays. The antioxidant potential varied from 18% to 83% (DPPH) and reached 74% (ABTS) at a concentration of 100 µg/mL. The anti-inflammatory assays indicated a BSA denaturation inhibition ranging from 45% to 80% and a membrane stabilization effect between 54% and 85%. Conclusions: CG-AgNPs exhibit substantial antibacterial, antioxidant, anti-inflammatory, and anticancer activities, underscoring their pharmaceutical potential, particularly for combating antibiotic-resistant pathogens and gastric malignancies. Full article

The increasing demand for bricks has raised environmental concerns related to natural clay depletion, land degradation, and agricultural waste disposal. To address these challenges, this study utilizes rice husk ash (RHA) as a sustainable partial replacement for clay in fired clay bricks. Brick mixtures were casted with varying RHA dosages (up to 80%), and the effect of 2% lime addition was also examined. Mixtures were fired at 1000 °C and 1200 °C and were tested for compressive strength, flexural strength, and water absorption. Microstructural and mineralogical characteristics were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). At 1000 °C, increasing RHA content and lime addition increased porosity and reduced mechanical strength due to limited vitrification. In contrast, firing at 1200 °C promoted extensive verification and densification, resulting in improved strengths surpassing the severe-weathering requirements of ASTM C62. Compressive strengths of 74.62 MPa and 52.55 MPa were achieved for bricks containing 20% and 40% RHA, respectively, exceeding ASTM C62 severe weather grade requirements. Results demonstrate that RHA can be utilized at high replacement levels when appropriate firing conditions are applied, supporting sustainable fired brick production and agricultural waste valorization. Full article

Lignocellulose biomass (LB) has gained interest as a second-generation renewable feedstock for producing bio-based products within a circular economy framework. Hemp hurds, a byproduct of industrial hemp processing, are one of the LB feedstocks that have gained attraction. This study examines the physicochemical properties of hemp hurds to evaluate their suitability as substrates for bioproduct synthesis. The chemical analysis of hemp hurds showed that the polysaccharide content is 53.4%, lignin is 20.8%, extractives are 15%, and ash is 4.35%. The moisture content is 6.34%, and the density is 1.0016 g/mL, indicating low porosity and a small surface area, which limits enzyme access to cellulose. Structural analysis using X-ray diffraction (XRD) indicated a crystallinity index of 40.20%, and the Fourier Transform Infrared Spectrophotometer (FTIR) confirmed the characteristic peaks representing cellulose, hemicellulose, and lignin at 3332 cm⁻¹, 1734 cm⁻¹, and 1510 cm⁻¹, respectively. The Scanning Electron Microscope (SEM) revealed a tightly packed surface with smooth, low porosity, whereas the Thermogravimetric Analyser (TGA) indicated decomposition in phases for hemicellulose, cellulose, and lignin. The structural and chemical findings of hemp hurds characterisation suggest that they are a suitable raw material for producing various bio-based materials. Full article

The rising environmental burden of Portland cement production has intensified the demand for eco-friendly binders that support sustainable construction. This study investigates the development and performance of eco-friendly self-compacting geopolymer concrete (SCGC) produced from industrial by-products, including fly ash (FA), ground granulated blast furnace slag (GGBFS), silica fume (SF), metakaolin (MK), and glass waste powder (GWP). Twenty-one binder formulations were evaluated for fresh-state workability, mechanical performance, durability, and microstructural characteristics under different curing regimes. Fresh properties were assessed using slump flow, V-funnel, L-box, and J-ring tests, while hardened-state evaluations included compressive and flexural strength, Young’s modulus, and water absorption. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were performed on selected mixes to examine microstructural features and crystalline phase development. Results highlight a strong dependency of SCGC performance on binder composition and curing conditions. Mixes rich in GGBFS and SF demonstrated superior mechanical and durability performance, achieving compressive strengths of up to 102.4 MPa under water curing and 107.6 MPa under heat curing, along with negligible water absorption, reflecting a dense and well-developed gel matrix. SEM micrographs confirmed homogeneous, compact microstructures in high-performing mixes, while XRD analysis revealed broad amorphous humps indicative of well-formed N-A-S-H and C-A-S-H gel phases with minimal crystalline residues. In contrast, FA-dominant mixes displayed delayed strength development, and MK-GWP-rich systems exhibited higher porosity and reduced strength. This study underscores the significance of precursor synergy, optimized curing strategies, and microstructural refinement in tailoring SCGC for high-performance, durable, and low-carbon applications in sustainable construction with values ranged from 38.64 GPa (Mix 21) to 25.04 GPa (Mix 19) at 28 days. Stiffer mixes corresponded to denser matrices containing GGBFS and silica fume, whereas lower values were linked to weaker bonding and higher porosity. Full article

The work studied the effect of high-temperature annealing on the phase composition, microstructure, and mechanical properties of an AlSn10Pb10 vol.% alloy obtained by laser powder bed fusion (LPBF). For this purpose, a series of anneals was carried out in the temperature range of 200–500 °C with a duration of 30 min. Using X-ray diffraction, it was determined that the annealed samples had a three-phase structure consisting of Al, β-Sn, and α-Pb phases, with a gradual decrease in their lattice elastic strain and dislocation density as the heating temperature increased. Analysis of the obtained SEM images revealed that these changes were accompanied by the coarsening of Sn and Pb inclusions and growth of the pure aluminum areas. As a result of the described structural changes with increasing annealing temperature, the ultimate compressive strength of the alloy monotonically decreased from 108 MPa (in the as-built state) to 75 MPa after annealing at 500 °C. The alloy’s ductility (strain at peak stress) also improved and reached a maximum of 26% after annealing at 400 °C. Compression test results showed that the optimal combination of ductility and strength of the LPBF-processed AlSn10Pb10 alloy was observed after annealing at 400 °C. Full article

Mullite (Al₆Si₂O₁₃), an aluminosilicate with remarkable thermal and dielectric properties, is a promising material for advanced electronic applications. This study focuses on a sintered mullite composite and examines its structural, morphological, dielectric, and electrical properties. X-ray diffraction and scanning electron microscopy analyses confirm a well-defined crystalline structure and a homogeneous microstructure. Impedance spectroscopy measurements reveal a high relative permittivity at low frequencies, dominated by interfacial and jump polarization mechanisms. Electrical conductivity follows Jonscher’s double-power law, reflecting mixed ionic and electronic conduction due to contributions from grains and grain boundaries. Analysis of the Nyquist diagrams shows a marked decrease in resistances with increasing temperature: The grain resistance decreases from 21.87 MΩ to 4.85 MΩ, while that of the grain boundaries decreases from 89.44 MΩ to 5.94 MΩ between 450 °C and 900 °C. In addition, the relative permittivity increases sharply with temperature, from 25 × 10³ to 350 × 10³ at 1 kHz and from 200 to 1 × 10³ at 1 MHz over the same temperature range, highlighting the dominant influence of temperature and low frequencies on polarization mechanisms. These results confirm the strong potential of sintered mullite for electronic applications. The activation energy of the grain and grain boundary were determined to be E_a,g = 0.18 eV and E_a,bg = 0.22 eV, respectively. Full article

Carbide lime (CL) and powdered glass (PG), as industrial by-products, possess significant potential as eco-friendly soil amendment materials. This paper presents a systematic investigation into the effectiveness and reaction mechanisms of a composite material comprising CL and PG for stabilizing dispersive soils. A systematic experimental program was designed with varying CL (0.5–6.5%) and PG (4–16%) contents, along with curing ages of 1, 7 and 14 days. Macroscopic properties, including dispersibility and permeability, were evaluated through pinhole, mud ball, and permeability tests, while phase composition and microstructural evolution were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results demonstrate a pronounced synergistic effect between CL and PG at optimal ratios: soil dispersibility is markedly improved when CL ≥ 2.5% and PG ≥ 8%, non-dispersive behavior is achieved at all curing ages with CL between 4.5 and 6.5% and PG between 4 and 16 permeability coefficient decreases significantly with increasing material content; for instance, increasing CL from 2.5% to 6.5% (at 16% PG) reduces the permeability coefficient by over 50%. Microstructural analysis reveals that CL supplies Ca²⁺ and an alkaline environment, whereas PG provides reactive SiO₂ and Al₂O₃. Their interaction facilitates ion exchange and pozzolanic reactions, leading to the formation of C–S–H and C–A–S–H gels. These cementitious products effectively fill pores and bond soil particles, thereby enhancing structural stability. This study confirms that the CL-PG composite is an efficient and sustainable soil stabilization material. It provides novel insights into the synergistic mechanisms and optimal dosage range, offering valuable theoretical and practical guidance for the resource utilization of industrial by-products in geotechnical engineering. Full article

Boron nitride is considered a promising material for solid-state hydrogen storage due to its high thermal and chemical stability up to ~1000 °C, depending on the atmosphere, as well as its ability to form defect-rich structures with enhanced sorption activity. Despite the growing interest in modified BN systems, systematic studies on the effect of multicomponent modification induced by the addition of carbon, titanium, and aluminum on the structural and phase evolution of boron nitride during high-energy mechanical alloying remain limited to date. In this work, the structural-phase and morphological changes in boron nitride-based composites modified by the addition of carbon, titanium, and aluminum, synthesized by high-energy mechanical alloying, were investigated. The structural state and morphology of the materials were analyzed using X-ray diffraction, scanning electron microscopy, particle size analysis, and thermal analysis. It is shown that mechanical alloying leads to a progressive breakdown of the layered hexagonal BN structure and the formation of an amorphous-like, defect-rich state without the formation of new crystalline phases. The main stage of amorphization occurs within 30–60 min, after which structural disordering reaches saturation. Increasing the mechanical alloying time to 120 min does not result in significant changes in the phase state; however, it is accompanied by a reduction in agglomeration and the formation of a more homogeneous powder morphology, characterized by narrower particle size distributions, smoother particle surfaces, and more uniform spatial dispersion of components. It was established that the nature of the added component significantly influences the kinetics of structural transformations: carbon accelerates amorphization, titanium intensifies fragmentation and defect accumulation, whereas aluminum exhibits a stabilizing effect. In multicomponent BN–C–Ti–Al systems, a synergistic combination of these effects is observed, leading to the formation of metastable, partially amorphous structures. Based on a comprehensive analysis of structural and morphological data, the optimal mechanical alloying time was determined to be 120 min, providing a saturated amorphous-like structural state combined with improved microstructural homogeneity. The obtained defect-rich boron nitride structures can be considered a promising basis for further studies in the field of solid-state hydrogen storage. Full article