A 4 nm thick carbon layer was obtained by pulsed laser deposition in vacuum directly on the surface of an n-Ge wafer. The carbon played a role of an intermediate layer in Au/C-layer/n-Ge mesa-diodes allowing the formation of a photosensitive structure with a dark reverse current density of 0.026 A/cm2, a barrier height of 0.6 V and a maximum spectral sensitivity in the wavelength range of 1.4-1.6 mu m.

In addition to their visible motion such as swimming (e.g., with the help of flagella), bacteria can also exhibit nanomotion that is detectable only with highly sensitive instruments, and this study shows that it is possible to detect bacterial nanomotion using an AFM detection system. The results show that the nanomotion characteristics depend on the bacterial strain, and that nanomotion can be used to sense the metabolic activity of bacteria because the oscillations are sensitive to the food preferences of the bacteria and the type of surrounding medium.

The regularities of ion synthesis of gallium oxide nanocrystalline inclusions by implantation of gallium and oxygen ions into dielectric Al 2 O 3 films on silicon substrates and subsequent thermal annealing are considered. The composition of the implanted samples before and after annealing was investigated by X-ray photoelectron spectroscopy with layer -by -layer profiling. The formation of Ga-O chemical bonds was demonstrated, and after annealing gallium is predominantly in the fully oxidized state. According to X-ray diffraction data, the formation of beta -Ga 2 O 3 crystalline phase was confirmed. The study of photoluminescence of the synthesized samples revealed the presence of luminescence band, which is presumably caused by radiative recombination of donor -acceptor pairs.

Thin ferromagnet/heavy metal multilayer films are considered as prospective media for a magnetic recording and Co/Pd films are a good example of such materials. In this work, the magnetic properties and micromagnetic structure of Co/Pd multilayer films are studied with different bilayer thicknesses ([Co(0.3 x t nm)/Pd(0.5 x t nm)]10), but with the same ratio Co versus Pd. Transmission electron microscope and X-ray diffraction studies allow authors to suppose that the investigated films are highly mixed alloys. Magnetic force microscopy and Lorentz transmission electron microscopy showed the presence of various micromagnetic features in the films. Along with skyrmions that are well-known magnetic topological artifacts some new features are revealed, which are interpreted as 360 degrees domain walls, skyrmioniums and the combination of the above two. It is found that the type and density of micromagnetic features strongly depend on the bilayer thickness parameter (t). The effect is associated with the peculiarities of interfacial magnetic interactions in the samples with highly mixed interfaces. The tooling coefficient represents a useful tool of the electron beam evaporation technique enabling wide manipulation of micromagnetic particles, in particular, skyrmioniums that are currently considered a prospective media for current driven magnetic recording. The magnetic properties and micromagnetic structure of Co/Pd multilayer films with different bilayer thicknesses, but with the same ratio Co versus Pd are studied. A number of micromagnetic features in the films are revealed, such as skyrmions, 360 degrees domain walls, skyrmioniums and the combination of them. image

The main goal of this work is to highlight the connection between nanomotion and the metabolic activity of living cells. We therefore monitored the nanomotion of four different clinical strains of bacteria (prokaryotes) and the bacterial phagocytosis by neutrophil granulocytes (eukaryotes). All clinical strains of bacteria, regardless of their biochemical profile, showed pronounced fluctuations. Importantly, the nature of their nanomotions was different for the different strains. Flagellated bacteria (Escherichia coli, Proteus mirabilis) showed more pronounced movements than the non-flagellated forms (Staphylococcus aureus, Klebsiella pneumoniae). The unprimed neutrophil did not cause any difference in cantilever oscillations with control. However, in the process of phagocytosis of S. aureus (metabolically active state), a significant activation of neutrophil granulocytes was observed and cell nanomotions were maintained at a high level for up to 30 min of observation. These preliminary results indicate that nanomotion seems to be specific to different bacterial species and could be used to monitor, in a label free manner, basic cellular processes.

It has been established that the physicochemical properties of structures based on iron silicides formed by ion implantation of iron ions into silicon depend significantly on the time of subsequent high-temperature annealing. Objects with different geometric parameters are formed on the surface and the roughness increases. Annealing at 1000 C in an Ar atmosphere is accompanied by a decrease in the content of the Fe-Si chemical bonds during the first 60 seconds. The reason for the drop in thermal conductivity with increasing annealing temperature is the formation of silicide complexes.

Silicon compounds have a wide range of electrical properties. In particular, the possibility of creating thermoelectric converters based on them looks extremely attractive. The use of most silicides as thermoelectrics today is limited by their low efficiency. The development of approaches consisting in the creation of low-dimensional structures using non-equilibrium formation methods is one of the priority directions for improving the properties of thermoelectric generators. Determination of the effect of technological regimes on the structure, phase-chemical composition and thermoelectric properties of metal-silicide structures is a key task, the solution of which will allow creating highly efficient thermoelectric generators based on them. Thin-film structures with a layer thickness of ~50 nm formed at different growth temperatures by pulsed laser deposition on two types of substrates: sapphire and gallium arsenide coated with an Al2O3 nanolayer were studied in this work. On the formed samples, a chemical analysis and a study of the phase composition were performed. Chemical analysis was carried out by X-ray photoelectron spectroscopy with the chemical composition depth profiling. The phase composition was studied by Raman spectroscopy. In addition, analysis of the elements in the films was carried out by X-ray spectral microanalysis based on a scanning electron microscope. To determine the thermoelectric properties of the formed thin-film structures, the temperature dependences of the Seebeck coefficient and the electrical conductivity coefficient were recorded. The dependence of the thermoelectric characteristics of iron silicide films on the phase composition is analyzed. In particular, measurements of the thermoelectric properties of FeSix thin-film structures registered the manifestation of a strong thermoelectric effect in layers with the maximum number of chemical bonds between iron and silicon. The parameters of the growth process at which the most effective formation of iron-silicon chemical bonds is achieved were determined using the method of X-ray photoelectron spectroscopy. Line shifts from the beta phase of iron disilicide were found in the Raman spectra and the reasons for their appearance were proposed

Three-layer structures based on various multi-component films of III–V semiconductors heavily doped with Fe were grown using the pulsed laser sputtering of InSb, GaSb, InAs, GaAs and Fe solid targets. The structures comprising these InAsSb:Fe, InGaSb:Fe and InSb:Fe layers with Fe concentrations up to 24 at. % and separated by GaAs spacers were deposited on (001) i-GaAs substrates at 200 °C. Transmission electron microscopy showed that the structures have a rather high crystalline quality and do not contain secondary-phase inclusions. X-ray photoelectron spectroscopy investigations revealed a significant diffusion of Ga atoms from the GaAs regions into the InAsSb:Fe layers, which has led to the formation of an InGaAsSb:Fe compound with a Ga content up to 20 at. %. It has been found that the ferromagnetic properties of the InAsSb:Fe magnetic semiconductor improve with an increasing Sb:As ratio. It has been concluded that the indirect ferromagnetic exchange interaction between Fe atoms occurs predominantly via Sb atoms.

It has been established that the physicochemical properties of structures based on iron silicides formed by ion implantation of iron ions into silicon depend significantly on the time of subsequent high-temperature annealing. Objects with different geometric parameters are formed on the surface and the roughness increases. Annealing at 1000 o C in an Ar atmosphere is accompanied by a decrease in the content of the Fe-Si chemical bonds during the first 60 seconds. The reason for the drop in thermal conductivity with increasing annealing temperature is the formation of silicide complexes. Keywords: iron silicide, thermoelectric, ion implantation, chemical composition, X-ray photoelectron spectroscopy.

Low-temperature device-quality GaAs layers with high resistivity were obtained by pulsed laser deposition. The properties of GaAs layers are sensitive to the process temperature. At a growth temperature of less than 300 o C, the layers have low electron mobility and a shift of the GaAs stoichiometry towards the region of arsenic enrichment at a level of 1-2 at.%. At a growth temperature of more than 300 o C, the layers show an improved crystalline quality. The dependence of the relative intensity of the As 3d photoelectron line on the growth temperature confirms this trend with a change in the growth temperature. Keywords: pulsed laser deposition, Hall effect, X-ray photoelectron spectroscopy.

Low-temperature device-quality GaAs layers with high resistivity were obtained by pulsed laser deposition. The properties of GaAs layers are sensitive to the process temperature. At a growth temperature of less than 300°C, the layers have low electron mobility and a shift of the GaAs stoichiometry towards the region of arsenic enrichment at a level of 1–2 at.%. At a growth temperature of more than 300° C., the layers show an improved crystalline quality. The dependence of the relative intensity of the As 3d photoelectron line on the growth temperature confirms this trend with a change in the growth temperature.

Lead-based ternary-chalcogenide thin films of the (PbTe)1−x(PbS)x system were obtained using the plasma-enhanced chemical-vapor-deposition (PECVD) technique under conditions of a nonequilibrium low-temperature argon plasma of an RF discharge (40.68 MHz) at a reduced pressure (0.01 Torr). High-purity elements were directly used as starting materials, namely Pb, S and Te. Plasma–chemical synthesis was carried out on the surface of c-sapphire and silicon substrate. The physicochemical properties of the films were studied using various analytical methods. The dependence of the Seebeck coefficient, resistivity and power factor on the structural properties and composition has been studied. The thermoelectric characteristics were found to be dependent on film composition. Upon the selection of optimal sulfur concentration, one can increase the power factor compared to single-phase PbS or PbTe films.

The oscillation mode of an atomic force microscope (AFM) was used to create a highly sensitive real-time detection system for antibiotic resistance. This mode allows one to evaluate the sensitivity or resistance of Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria to an antibiotic in 15–30 minutes. The analytical signal (changes in the amplitude-frequency characteristics of the cantilever) is based on the metabolic activity of bacteria. Bacteria were placed on the cantilever and causing it to oscillate with high amplitude. If the bacteria are sensitive to the antibiotic, the amplitude drops statistically significant within 15–30 minutes, if the bacteria are resistant, then the amplitude either does not change or increases. The results were comparable with the disk diffusion method.

The ion-beam synthesis of Ga2O3 nanocrystals in dielectric matrices on silicon is a novel and promising way for creating nanomaterials based on gallium oxide. This research studies the regularities of changes, depending on the synthesis regimes used, in the chemical composition of ion-implanted SiO2/Si and Al2O3/Si samples. It has been shown that the formation of Ga-O chemical bonds occurs even in the absence of thermal annealing. We also found the conditions of ion irradiation and annealing at which the content of oxidized gallium in the stochiometric state of Ga2O3 exceeds 90%. For this structure, the formation of Ga2O3 nanocrystalline inclusions was confirmed by transmission electron microscopy.

A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocrystals of this compound in a SiO2/Si dielectric matrix has been proposed. The influence of the order of irradiation with ions of phase-forming elements (gallium and oxygen) on the chemical composition of implanted layers is reported. The separation of gallium profiles in the elemental and oxidized states is shown, even in the absence of post-implantation annealing. As a result of annealing, blue photoluminescence, associated with the recombination of donor–acceptor pairs (DAP) in Ga2O3 nanocrystals, appears in the spectrum. The structural characterization by transmission electron microscopy confirms the formation of β-Ga2O3 nanocrystals. The obtained results open up the possibility of using nanocrystalline gallium oxide inclusions in traditional CMOS technology.

A new method for the formation of a diluted magnetic semiconductor based on gallium arsenide doped with iron and manganese atoms is considered. The method consists in diffusion doping during pulsed laser deposition in vacuum. Using the method of X-ray photoelectron spectroscopy, the profile of the chemical elements distribution was obtained. The magnetic phases influence on the behavior of the magnetic field dependence of the Hall resistance is analyzed. The technological parameters for the growth of the structure exhibiting ferromagnetic properties at room temperature were selected.

Abstract—Atomic force microscopy was used for detection of cantilever nanovibrations as a result of the metabolic activity of Escherichia coli. Poly-L-lysine is shown to be effective as an adhesion solution in promoting bacterial cell adhesion process onto the cantilever and has no effect on the metabolic activity of these bacteria. Analysis of the variance has been used to track the resonance of the cantilevers: a cantilever that was functionalized with poly-L-lysine (control) and a cantilever with bacteria attached (experiment). The amplitude measures were analyzed and it was found that there was a statistically significant difference between the averages. It has been demonstrated that the methods used in clinical practice for detecting bacteria and measuring their response to antibiotics require a few days; in contrast, atomic force microscopy would permit assessment of the susceptibility of a microorganism to antibiotics within 1 h.

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.

III–V/Ge/Si(001), III–V/Ge/SOI(001), and III–V/GaAs(001) heterostructures are fabricated and investigated. The Ge buffer layer for the III–V/Ge/Si structure is grown by vapor deposition onto a Si(001) substrate via the decomposition of monogermane on a “hot wire”. In the case of III–V/Ge/SOI, the Ge buffer layer is obtained on a SOI(001) substrate by molecular-beam epitaxy via two-stage growth. The III–V layers are grown by metalorganic chemical-vapor deposition. It is shown that Ge/SOI formed by molecular-beam epitaxy using two-stage growth allows the fabrication of III–V layers that are highly competitive with those formed on Ge/Si in terms of crystalline and optical quality.

Staphylococcus aureus induces the expression of VCAM-1, P- and E-selectins on the endothelial cells of the EA.hy926 cell line but, at the same time, causes the significant suppression of the force and work of adhesion between these receptors of endotheliocytes and the receptors of neutrophils in an experimental septicemia model. Adhesion contacts between the receptors of neutrophils and endotheliocytes are statistically significantly suppressed under non-opsonized and opsonized S. aureus treatment, which disrupts the initial stage of transendothelial migration of neutrophils—adhesion. Thus, S. aureus causes the arrest of neutrophils in the bloodstream in an experimental septicemia model.