Abstract This study reports the green synthesis of silver nanoparticles (AgNP@SA) using an extract from the medicinal plant Stryphnodendron adstringens as both the reducing and stabilizing agent. The resulting nanoparticles were spherical, with an average diameter of 12 ± 2 nm, and exhibited high colloidal stability, as indicated by a zeta potential of −28 ± 6 mV. Their formation and physicochemical properties were confirmed by UV–vis, TEM, EDS, STEM, DLS, XPS, FT-IR, UHPLC-HRMS/MS, and 1H-NMR analyses. Spectroscopic data showed that tannins and other phenolic compounds in the plant extract were primarily responsible for the reduction of Ag+ ions and stabilization of the nanoparticles, pointing to the involvement of related flavonoid derivatives. UHPLC-HRMS/MS analysis, interpreted through the GNPS database, further demonstrated the absence of epigallocatechin in the final nanoparticle system, supporting its proposed role as the reducing agent during nanoparticle synthesis. Biological assays demonstrated that AgNP@SA exhibited broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria. 1H-NMR-based metabolomic profiling of Staphylococcus aureus under AgNP@SA stress revealed significant metabolic disruption, including decreased levels of leucine and valine and increased levels of lysine, acetate, and betaine, suggesting the induction of cellular stress and impairment of essential metabolic pathways. Overall, these findings highlight the potential of green-synthesized AgNP@SA as effective antimicrobial agents and reinforce the value of plant-mediated nanoparticle synthesis for biomedical applications.

The Schottky diode is one of the main elements in SiC-based devices. In this paper, $\text{Ni}_{\mathrm{x}} \text{Si}_{\mathrm{y}}$ films, formed by sintering of Ni on SiC substrate, were characterized in order to evaluate their performance as ohmic contact in Schottky diodes. The films fabricated using long and short time treatment, with and without preheating condition were investigated. Short-time treatment with a preheating step promoted the formation of more uniform and homogeneous nickel silicide films, which exhibited ohmic behavior.

This work aims to emphasize the potential of laser drilling as a practical and efficient method for fabricating through-silicon vias (TSVs). In this study, TSVs were produced using a 1064 nm low-cost fiber laser, followed by chemical polishing in an $\text{HF}: \text{HNO}_{3}$ solution. Three samples were analyzed, differing only in the number of laser passes applied. Increasing from a single pass to six passes resulted in noticeable changes in wall roughness and via enlargement. Additionally, Raman spectroscopy was carried out to assess the crystalline integrity of the silicon surrounding the TSVs, revealing no significant structural variations. These results suggest that laser drilling, when combined with chemical treatment, represents a promising alternative to conventional etching techniques, especially in terms of process speed and cost efficiency. However, additional work is needed to improve the fabrication parameters and achieve better control over the via geometry.

Since ultrathin films of 2 nm thickness with Ni and W revealed interesting aspects in Schottky barrier diodes in previous works, exhibiting effective quality of the interface and thermal stability under electrical characterizations. This work presents data obtained using Ta as Schottky contact, even though it is often used as Ohmic contact, but due to its refractory properties and low work function, the result could be favorable to low voltage drop devices in power electronics. Under the development of the work, a range of annealing processing was conducted to verify the phenomena involved combining tantalum ultrathin films. After electrical tests under I–V curves, a range of Schottky barrier heights (SBHs) was noticed without Fermi level pinning, following a highlighted device that demonstrated results of ideality of around 1, SBH of 0.8 eV, alto showing high rectification ratio and low reverse leakage current, around 10−6 A at −200 V. To finish the work, XPS and SEM characterization were carried out to provide interface structure details and reveal tantalum oxides and carbides, where they probably contribute to the Schottky behavior, and the values achieved.

The hybrid structure of stainless steel films decorated by copper oxide nanoparticles was fabricated using dc sputtering technique following the thermal oxidation method. The character of oxidation and chemical stability over time were evaluated using energy-dispersive X-ray and X-ray photoelectron spectroscopies. The relatively high amount of the CuO phase in nanoparticles and a low degree of oxidation of stainless steel make this hybrid structure a promising candidate for mono- and disaccharide sensing applications.

We report that mechanical deformation of graphite with cavity shock waves introduces a new group of charge carriers, with both effective mass and native concentration one order of magnitude above those found in the pristine material. Their nature, however, remains quasi-2D. Our results show that defects introduced during mechanical exfoliation have the potential to unlock oscillatory behavior above 50 T in graphite, thus providing a new probe for field-induced electronic phase transitions in the material.

Highly electrically and thermally conducting films of expanded graphite/polymer nanocomposites were fabricated using an approach based on solution mixing methods. The use of Hydroxyethylcellulose and benzylic alcohol based solutions provides efficient dispersion and better exfoliation of multilayer graphene (nanographite) flakes that are further aligned in extended 2D layers forming continuous conductive pathways during lamination (hot calendering) process. Very high electrical conductivity (190 S/cm) was obtained for fabricated layered films. In contrast, for films produced by a conventional mixing and deposition method with acrylic copolymer and the same nanographitic material, with flakes randomly distributed within the composite, much lower conductivities (2.4 S/cm) were obtained.

Approaches such as the modification of substrate design and the use of different types of underfill/epoxy mold compound were proposed to solve the delamination problem in system-in-packaging devices (SiP). Energy dispersive spectroscopy, scanning electronic and acoustic microscopy were employed to evaluate the proposed changes in device structure. The effects of dispensing and curing temperature as well as of viscosity on the underfill penetration ability under the component region were investigated. It was found that besides the excess of flux residue, the root cause of the delamination/expansion problem in SiP devices submitted to high temperatures is the presence of a large size of voids under the component. The use of a substrate design with cavity under the component region containing two entrances and the application of underfill was considered as a solution of the delamination problem. The reliability of this strategy was confirmed by a large sample size of fabricated devices.

The highly conductive composite based on graphite nanobelts/ultra-high-molecular-weight polyethylene (UHMWPE) was developed using hot calendering at temperatures below the polymer melting point. The fabricated material exhibits excellent electrical conductivity (up to 40 S cm−1), high efficiency of electromagnetic interference shielding (near 35 dB for 100 μm thick samples) and good mechanical properties (flexibility and mechanical strength). These superior characteristics are the result of synergistic combination involving superior mechanical properties of the polymer, perfect transport characteristics of the filler and the specific method of fabrication allowing for formation of a segregated anisotropic conductive network with a low percolation threshold (0.42 vol %).

SU-8 polymer is an excellent platform for diverse applications due to its high aspect ratio of micro/nanostructure fabrication and exceptional physicochemical and biocompatible properties. Although SU-8 polymer has often been investigated for various biological applications, how its surface properties influence the interaction of bacterial cells with the substrate and its colonization is poorly understood. In this work, we tailor SU-8 nanoscale surface properties to investigate single-cell motility, adhesion, and successive colonization of phytopathogenic bacteria, Xylella fastidiosa. Different surface properties of SU-8 thin films have been prepared using photolithography processing and oxygen plasma treatment. A more significant density of carboxyl groups in hydrophilic plasma-treated SU-8 surfaces promotes faster cell motility in the earlier growth stage. The hydrophobic nature of pristine SU-8 surfaces shows no trackable bacterial motility and 5-10 times more single cells adhered to the surface than its plasma-treated counterpart. In addition, plasma-treated SU-8 samples suppressed bacterial adhesion, with surfaces showing less than 5% coverage. These results not only showcase that SU-8 surface properties can impact the spatiotemporal bacterial behavior but also provide insights into pathogens' prominent ability to evolve and adapt to different surface properties.

The possibilities of doping carbon layers grown by pulsed laser deposition with transition-metal impurities are analyzed. The composition and optical and electrical parameters of structures on GaAs and Si/SiO2 substrates are studied. It is shown that the introduction of such atoms as Fe ones modifies the magnetic properties of layers, which are responsible for nonlinear magnetic-field dependences of the Hall effect at temperatures of up to 300 K.

The problem of delamination in system-in-package devices was studied. It was found that this type of failure was induced by solder flux excess trapped underneath electronic components and/or around the big solder area. Several approaches to solve this problem were proposed.

We report the occurrence of ferromagnetic-like anomalous Hall effect (AHE) below $30$ mT in bismuth single and policrystals. The signatures of ferromagnetism in transport are not corroborated in magnetization measurements, thus suggesting the induction of non-intrinsic magnetism at surfaces and grain boundaries in bismuth. The suppression of the AHE with the increase of magnetic field and temperature coincides with previous reports of superconductivity in Bi, suggesting an interplay between the two phenomena.

Herein, we demonstrate the prototype of a combined flexible pressure sensor based on ultrathin multiwall carbon nanotubes (MWCNTs) and graphite nanobelts (GNBs) films embedded in polydimethylsiloxane (PDMS). A simple and scalable modified Langmuir–Blodgett method was used for deposition of both MWCNT and GNB films. The use of two types of carbon nanostructures (nanotubes and GNBs) with distinctly different mechanical properties allowed obtaining enhanced dynamic range for pressure sensing. Short response time, good sensibility and flexibility, and low power consumption for enhanced pressure range make possible applications of the sensor for healthcare monitoring and as a component in the human–machine interfaces application.

Исследованы возможности легирования углеродных слоев, выращиваемых методом импульсного лазерного нанесения, примесями переходных металлов. Изучены состав, оптические и электрические параметры структур на подложках GaAs и Si/SiO2. Показано, что введение таких атомов, как Fe, модифицирует магнитные свойства слоев, вызывая нелинейные магнитополевые зависимости эффекта Холла при температурах вплоть до 300 K. Ключевые слова: импульсное лазерное нанесение, углеродные слои, легирование, примеси переходных металлов.

Экспериментально обнаружено существенное (почти на два порядка величины) увеличение интенсивности фото- и электролюминесценции диодной структуры с квантовой ямой InGaAs/GaAsSb/GaAs, слоем GaMnAs в качестве спинового инжектора и контактным покрытием из пленки многослойного графена. Результат объясняется возможным образованием гибридной системы многослойного графена и полупроводника GaAs под воздействием излучения He-Ne-лазера, приводящим к изменению зонной диаграммы гетероструктуры. Ключевые слова: светоизлучающая структура, GaAs, квантовая яма, многослойный графен, люминесценция, лазерное воздействие.

For graphitic materials, Raman technique is a common method for temperature measurements through analysis of phonon frequencies. Temperature (T) induced downshift of the bond-stretching G mode (ΔG) is well known, but experimentally obtained thermal coefficients ΔG/ΔT vary considerably between diverse works. Further, ΔG/ΔT coefficients usually were evaluated for relatively low temperatures and found to differ strongly for mono, a few and multilayer graphene. We studied G band behavior in freely suspended multilayer graphene flakes (or graphite nanoflakes) under localized heating by a laser beam. Analysis of Stokes and anti-Stokes signals showed that G band has a complex structure and can be deconvoluted into several peaks that demonstrate distinctly different behavior under heating. A plausible assumption is that these peaks correspond to several groups of graphitic layers (surface, near-surface and bulk) and then different thermal coefficients were determined for these groups. This behavior can be explained by decreasing interaction between surface layers and underlying material at high temperatures that affects especially vibrational properties of a few outermost layers. Estimates of temperatures using anti-Stokes/Stokes intensity ratio (IaS/IS) were also done to give results comparable with those obtained from G band downshift, TΔG ≈ TaS/S, supporting the proposed model. The range of temperatures obtained by laser heating, as evaluated by both methods, was from 450 to 1200 K.

A significant (almost two orders of magnitude) increase in the intensity of photo- and electroluminescence of a diode structure with an InGaAs/GaAsSb/GaAs quantum well, GaMnAs layer as a spin injector, and contact coating of a multilayer graphene film has been experimentally detected. The result has been explained by the possible formation of a hybrid system of multilayer graphene and GaAs semiconductor under the influence of He–Ne laser radiation, which leads to a change in the band diagram of the heterostructure.

In this work we propose multilayer graphene (MLG) nanobelts for high current interconnections with single wall carbon nanotubes (SWCNT) and compare these with metal contacts. MLG contacts were directly printed on the SWCNT, without any additional metal parts, demonstrating the possibility to use these materials as interconnections in microelectronics. Different work function metals Al, Ti and Pd were probed for the lowest contact resistance with the SWCNT. Ti contacts demonstrated the best results among the metals owing to its work function being closest to the SWCNT and therefore giving the lowest Schottky barrier. Even though Ti contacts show the lowest contact resistance, the current density for MLG contacts was higher, giving the best results for high current interconnection applications. Moreover, MLG contacts show a stable and repeatable resistance decrease under high current conditions. Heat treatment of the MLG and metal contacts was completed in vacuum, in order to further reduce the contact resistance and optimal heat treatment conditions were found at 600 °C.