Abstract The spectrum of slow electromagnetic waves (EMWs) existing in a left-handed medium based on a magnetoactive plasma metamaterial has been theoretically studied. The metamaterial under study is a strip waveguide completely filled with longitudinally magnetized cold electron plasma containing a periodic structure made from ideally conducting split-ring resonators. It is shown that there exists

Abstract A novel planar microstrip meander-line slow-wave structure (SWS) on dielectric substrate for a miniature low-voltage millimeter-band traveling-wave tube (TWT) with a high-aspect-ratio sheet electron beam is proposed. Main electromagnetic parameters of the SWS were studied. Using of such a slow-wave structure may lead to increase of the gain and output power of the TWT amplifier.

Abstract We have studied the growth of GaN layers by the metalorganic vapor phase epitaxy (MOVPE) on sapphire substrates at various reactor pressures, including ones above the atmospheric level. It is established that the epitaxial growth at higher pressures does not affect the crystalline perfection of epilayers, their electron mobility, and background impurity level, but leads to the formation of

Abstract Sputtering yields and their angular dependences for tungsten bombarded with beryllium (Be) and neon (Ne) ions were calculated using the molecular dynamics method, showing good agreement with experiment for Ne–W collisions. Data for the Be–W interaction are necessary for calculating the impurity supply during bombardment of the diverter material (W) into plasma of the ITER tokamak. A model

Abstract High-speed photodetectors (PDs) based on InGaAs/GaAs quantum well-dot (QWD) nanostructures with the frontal-end and back-end input of radiation have been studied. A PD with 40 rows of QWDs exhibited a spectral responsivity of up to 0.4 A/W in the 950–1100 nm optical range at a –5-V bias voltage. The decay time constant of pulsed response for PDs with an input area of 1.4 × 10–4 cm2 was ~250

Abstract The results of developing a new type of the gas-analytical device for detection of hard-volatile active organic compounds such as drugs, psychotropic preparations and their metabolites, environmental contaminants have been presented. It is based on the principle of thermodesorption in combination with surface ionization of analyte molecules. The trace amounts of an analyte (beginning with

Abstract It is shown that the photoresponse threshold and photosensitivity in a photoresistor material based on silicon doped with manganese atoms with the formation of the Mn4B nanoclusters can be changed by varying the electric field in the range of 0.1–30 V/cm. It has been found that, by changing the electric field, one can shift the photoresponse threshold of the samples at T = 100 K from 4.6 to

Abstract Metal–ferroelectric–semiconductor Pb(ZrTi)O3/Ba0.2Sr0.8TiО3/Si(001) heterostructures have been synthesized by radiofrequency cathode sputtering. It has been established that the Pb(ZrTi)O3 films are single-phase and textured and the degree of predominance of one crystallographic orientation over another (110 or 001) is determined by the Ba0.2Sr0.8TiO3 sublayer thickness. It is shown that,

Abstract Temperature-dependent decline in the external quantum efficiency (EQE) of blue light-emitting diodes, which is at a maximum at j < 10 A/cm2 and becomes stronger with temperature increasing to 400 K, is due to the buildup of the loss for the nonradiative recombination upon carrier tunneling that involves traps and phonons. As the p–n junction becomes open at j > 40 A/cm2 the decline in the

Abstract The results of an experimental study of the interfacial tension and surface wettability in the nanosuspension/oil/rock system are given. The effect of the concentration and size of silicon oxide nanoparticles on the coefficient of interfacial tension and the contact angle of wetting has been systematically studied for the first time. A wide range of weight concentrations of nanoparticles (from

Abstract The behavior of characteristics of localized plastic flow autowaves in a Fe–Cr–Ni alloy in the temperature interval of 143 ≤ T ≤ 420 K (0.34 ≤ T/ΘD ≤ 1), where ΘD = 420 K is the Debye temperature (parameter), is considered. It is shown that the product of the length and propagation rate of the autowave λVaw in this interval decreases with temperature. At the same time, the ratio of this quantity

Abstract It is shown using the methods of acoustic emission in the version of linear location and internal friction that, upon extension of an initially equilibrium composition (carbon-fiber-reinforced plastic), nonrelaxed stress is accumulated at sites of explosive creation of microcracks. This process is caused by incomplete relaxation redistribution of the stored energy/elastic strain according

Abstract Peculiarities of the motion of one and two supercavitating strikers in water upon their simultaneous entry into water at speeds exceeding the speed of sound in the medium are considered. Conditions have been developed to ensure nondestructive entry of strikers into the water and stable movement along an aiming trajectory in the transonic speed range. A stable joint motion of two strikers in

Abstract Using simple models, analytical estimates of quantum capacitance CQ are obtained for an infinite sheet, a nanoribbon, and a chain of two-dimensional analogs of the ANB8 – N compounds with a hexagonal structure (graphene-like compounds). It is demonstrated that there is a nonmonotonic dependence of CQ on the electrostatic potential.

Abstract We have studied the influence of the carbon black content on the phase composition of a polymer composite material based on ethylene vinyl acetate. It is established that there exists an additional (high-temperature) crystalline polymer phase the relative fraction of which depends on the content of carbon black. Saturation of the carbonaceous polymer composite with peroxide significantly influences

Abstract The results of studying the conditions for obtaining an atomically smooth surface of GaSb substrates are presented for the first time. It has been shown experimentally that it is possible to improve the surface quality of the samples by changing the annealing conditions. The smallest roughness of 1.3 nm was obtained for an annealing time of 16 min at a temperature of 650°C in a flow of trimethylantimony

Abstract The quality of the crystallographic texture is analyzed for thin ribbons made of ternary Cu–40% Ni–Me (Me = Nb, Mo, or W) alloys, which are promising materials for epitaxial substrates. Optimal regimes of recrystallization annealing of ~100-μm-thick ribbons made of these alloys are determined, which provide perfect cubic texture with a fraction of {001}〈100〉 grains of more than 96%. The proposed

Abstract Constrained shear strain with subsequent annealing was used to fabricate an in situ Al−Nb metal matrix composite with the fraction of an Al3Nb intermetallic phase of 25 at %. The composite microstructure was studied. The emission efficiency of the Al−Nb composite samples in a glow discharge was determined, along with those of aluminum and niobium as cold cathodes. The difference in the glow

Abstract Results are reported of using subcontact layers with energy gap width Eg of 0.35 to 0.8 eV for obtaining low-resistivity electrical contacts to p-InP. An experimental dependence of the contact resistance on Eg of the subcontact material InxGa1 – xAs was obtained.

Abstract It is shown that the degree of damage of the near-surface layer of p-silicon can be estimated with the aid of a MoOx/p-Si selective contact, the current–voltage characteristics of which are highly sensitive to states on the silicon surface formed during the deposition of silicon oxide by method of magnetron sputtering.

Abstract A new approach to design an ultra-wideband device for blocking radio-controlled explosive apparatuses, in which a multi-channel processing unit based on a set of narrow-band radio signal receiving units with the introduction of noise interference into each channel has been replaced by a single-channel microwave photonic analogue using an optical recirculating circuit-based optoelectronic radio

Abstract It is shown using Mössbauer spectroscopy on 61Cu(61Ni) isotopes that dielectric metal oxides of divalent copper exhibit combined quadrupole and Zeeman interaction of 61Ni nuclei with local fields in copper sites, whereas superconducting metal oxides exhibit only quadrupole interaction of 61Ni nuclei. The valence contributions to the electric field gradient tensor on 61Ni2+ and 63Cu2+ nuclei

Abstract Near- and far-fields of quantum-cascade lasers emitting in the spectral range near 8 μm have been studied. For all laser samples with a ridge width of 20 and 50 μm, lasing on the fundamental waveguide mode with a divergence of ~50° was observed for all laser samples with a ridge width of 20 and 50 μm along the “fast” axis. Along the “slow” axis, a multimode lasing and a competition between

Abstract Results of successful experiments on the growth of gallium oxide (β-Ga2O3) crystals by the Czochralski method are reported. The influence of growth atmosphere on the crystalline perfection of obtained material has been studied. It established that high-quality transparent optical crystals can be obtained provided the atmosphere contains about 5 vol % oxygen. As-grown β-Ga2O3 crystals were

Abstract Electric breakdown of a thin film of polypropylene is accompanied by emission of the electromagnetic radiation pulse of about 400 ns duration with a spectrum consisting of three main frequencies. A relationship between the electric resistance of the breakdown channel and observed radiation spectrum is explained.

Abstract A highly sensitive terahertz (THz) detector based on a photoconductive antenna (PCA) with plasmonic amplification on the basis of an InGaAs/InAlAs superlattice heterostructure is proposed. A noticeable increase in the photocurrent recorded by a plasmonic PCA detector and the signal-to-noise ratio was experimentally detected compared to the same parameters for the PCA detector without plasmonic

Abstract The necessity to measure the longitudinal and transverse relaxation times T1 and T2 simultaneously for the purpose of controlling the state of a flowing liquid was substantiated if flow rate q can vary by two orders of magnitude. A novel method of determining T1 was developed. A differential-type nuclear magnetic spectrometer was designed to employ this method, which allows measuring T1 in

Abstract We have studied heterostructures based on short-period InGaAs/InGaAlAs superlattices (SLs) manufactured by molecular-beam epitaxy on InP substrates, intended for use as active regions in vertical-cavity surface-emitting lasers operating in a 1.3-μm spectral range. The heterostructures were characterized by measuring photoluminescence (PL) emission and X-ray diffraction. It is established that

Abstract We demonstrate the possibility of selective-area growth of ordered arrays of GaN nanowires by molecular beam epitaxy on SiOx/Si substrates patterned by photolithography with microspherical lenses without the preliminary formation of seed layers. The effect of the substrate temperature on the morphological properties of the obtained arrays of nanowitres is studied. The optimal growth parameters

Abstract A method for calculating the mutual inductance of a system of tightly wound coils through the energy of axially magnetized cylinders is proposed. Formulas for calculating 3D fields of a cylinder and coils expressed in terms of elliptical integrals are obtained. Тhe volume-average demagnetization factor of the cylinder is shown to be equal to the Nagaoka coefficient for the self-inductance

Abstract The [(Co0.88Fe0.12)/Cu]N synthetic antiferromagnet has been investigated by the spin wave resonance method over the entire range of angles of an external dc magnetic field to the film surface normal. The investigations have shown that the superlattice under study consists of two exchange-coupled magnetic subsystems, each manifested in the recorded spectra as a series of spin-wave modes. The

Abstract The current–voltage (I–V) characteristics of n-GaP–p-(InSb)1 – x(Sn2)x (0 ≤ x ≤ 0.05) heterostructures have been studied. At low voltages (V < 0.5 V), the I–V curve is described by the exponential law I = I0exp(qV/ckT), while at higher voltages (from 0.5 to 1.8 V) it obeys the power law I = AVm with various values of coefficient A and exponent m dependent on the voltage. At still higher voltages

Abstract The main limitation of the use of tip-enhanced Raman scattering (TERS) is due to the lack of reliable scanning probes. We present a simple procedure to manufacture TERS probes with highly reproducible characteristics that are reliable and provide sufficient enhancement. The procedure is based on the modification of conventional cantilevers of scanning probe microscopes by plasma etching, followed

Abstract The slope of an oval-trench dimple in the corridor package on the stabilized hydrodynamic section of the narrow channel has a dramatic effect on the anomalous intensification of the separated and vortex flows in the dimple, leading to a three- to fourfold decrease in the relative negative friction in the range of angles from 40° to 60°, an increase in the maximum velocity of separated and

Abstract The processes of structure formation in arc-PVD Ti–Cr–N coatings are studied by computer simulation methods. A new approach to defining the geometric space for determining the positions of atoms relative to the formed dimers and crystallites is proposed. The structure parameters are calculated, and the processes of structure formation in coatings at a potential of 120 V are studied.

Abstract We present the results of experimental studies of the modification of the surface layer of grade 316L steel by duplex treatment, including ion-plasma treatment under nitrogen followed by plasma activated chemical vapor deposition of hydrocarbon films doped with silicon and oxygen (a-C:H:SiOx). The mechanical properties of the steel surface (hardness, modulus of elasticity, plasticity index

Abstract Quantum dots (QDs) of CdSe, PbS, and InSb semiconductors in a multigrain layer of a planar-end microstructure have been studied. A model of an ordered QDs arrangement in a micron gap of the structure and a current flow along the lines of their series-parallel arrangement are considered. At low voltages (less than 8 V), electron transport is determined by thermal and tunnel emission from QDs

Abstract The magnetization process in the nanocomposite BiFeO3–Bi2Fe4O9 obtained by the glycine–nitrate combustion, was studied. The magnetic characteristics of the individual compounds BiFeO3 and Bi2Fe4O9 and of the composite were found to be substantially different. The new properties of the synthesized substance are ascribed to the exchange interaction on the interface between the phases.

Abstract A new method for epitaxial growth of cadmium sulfide (CdS) films in the metastable cubic phase by atomic-layer deposition on silicon substrates with a buffer layer of epitaxial silicon carbide has been developed. The growth of this CdS phase is provided by the low growth temperature (~180°C). The cubic phase was identified both by X-ray diffraction analysis and by spectral ellipsometry because

Abstract The influence of the conditions of gettering in high-resistivity silicon during fabrication of PIN photodiodes on reverse dark currents has been studied. It is shown that gettering using a combination of phosphorus ion implantation and deposition of a polysilicon film with subsequent doping of the substrate rear side with phosphorus at temperatures below 900°C leads to low values of the reverse

Abstract We have investigated the effect of the finishing layer of carbon fibers on the appearance of the triple-shape memory effect of polyurethane carbon fiber. Structural changes in a polyurethane sample reinforced with finished carbon fiber were determined using thermomodulated differential scanning calorimetry. The effect of the diffusion adhesion mechanism on the thermomechanical characteristics

Abstract An alternative technique for synthesizing high-temperature superconductor samples is proposed, in which superconducting layers should form on the surface of hard-melting Ho2BaCuO5 green phase grains immersed in the liquid phase BaCuO2 + CuO.

Abstract Results of studying properties of magnetooptical waveguide logic gates are presented. Simple logical operations can be implemented by changing photon states in a substance under the action of a modulating magnetic field. Varying the amplitude and orientation of the magnetic field relative to the light propagation direction, choosing the orientation of the polarizer and analyzer and appropriate

Abstract An increase in the reflection in the IR spectral range typical of a plasmon resonance in single crystals is observed in an InSb film formed by thermal evaporation in a vacuum on a CdS single crystal. Raman spectra demonstrate an approximately constant ratio between the amorphous and crystalline phases for InSb films on a CdS substrate, which is uncharacteristic of an InSb film on gallium–gadolinium

Abstract A model describing the nucleation of grain boundary nanopores in submicrocrystalline materials under intensive plastic deformation is proposed. The effect of internal stress fields from planar mesodefects, external hydrostatic pressure, and the degree of oversaturation with nonequilibrium strain-induced vacancies in a material on the pore nucleation rate is analyzed.

Abstract A technique for obtaining ablated CeO2 particles of nanodispersed composition has been developed. With the help of transmission electron microscopy and small-angle X-ray scattering diffractometry, it was found that the limiting particle size in a colloidal solution does not exceed 30 nm. It was established by spectroscopy of characteristic electron energy losses that the content of defects

Abstract It is shown using Mössbauer spectroscopy on 119Sn, 121Sb, and 125Te isotopes that the local structure of germanium atoms changes during crystallization of amorphous Ge2Sb2Te5 films (tetrahedral symmetry changes to the octahedral one), whereas the environment of antimony and tellurium atoms remains the same (the environment of antimony atoms it close to that in the Sb2Te3 compound).

Abstract When studying doped anisotypic heterostructures with Ga1 – xInxAsyP1 – y layers grown on InP substrates with an InP buffer layer by metal organic chemical vapor deposition, the presence of transition regions is revealed in the Ga1 – xInxAsyP1 – y layer from the side of the substrate in some of the samples, along which the arsenic content (y) increases from the interface with the InP layer

Abstract Film structures composed of several identical modules [Co(x)/a-Si(100)/Cu(70)], where the x value varies from 2 to 10 nm, are investigated as an anode material for liquid lithium-ion batteries. It is shown that relatively thick cobalt layers are effective diffusion barriers for silicon and copper atoms, as well as for lithium ions. This leads to a decrease in the capacitance characteristics

Abstract The concept of improving the linearity of the coordinate characteristic and accuracy of the coordinate indication of a position-sensitive detector when expanding its field of view has been considered. The diagonal-segment topology of the detector has been analyzed taking into account the influence of the optical signal inhomogeneities and the spatial distribution of photosensitivity on its

Abstract The problem of calculation of Kapitza contact thermal resistances between different materials is very urgent in view of the development of various nanosystems (computer electronic circuits, thermoelectric devices, quantum cascade lasers, etc.). An improved acoustic mismatch model is proposed for calculating Kapitza conductivities. A drawback of the current model is the use of the Debye approximation

Abstract A model is suggested for a quantitative analysis of the dependence of the dielectric function of hexagonal silicon carbide polytypes on photon energy in the range of 0.7–6.5 eV. The model, which is the sum of two Tauc–Lorentz oscillators (main and minor) with a common energy gap, is used to describe three hexagonal silicon carbide polytypes (4H, 15R, 6H) obtained in the same growth process

Abstract It is experimentally established that heating of the surface of water by continuous laser radiation at a 1.94-μm wavelength via optic fiber leads to the generation of two jets: a (i) submerged jet directed into the liquid and (ii) a counterjet directed upward into the atmosphere. The jets are generated upon coalescence of the gas cavity formed during the explosive boiling of water caused by

Abstract Results of comparative investigations of the pulse-switching characteristics of devices (kivotrons) based on the open discharge in molecular gases (oxygen and nitrogen) and their mixtures with helium are presented. The choice of oxygen and nitrogen is determined by the fact that the coefficients of electron emission under impact of their heavy particles are much higher as compared to that

Abstract Si nanophases and nanolayers were obtained by bombardment with Ar+ ions followed by annealing at various depths of silicon oxide. As ion energy E0 varies from 10 to 25 keV, the average depth of Si nanophase formation varies from 15 to 25 nm. It is shown that, as the sizes of Si nanophases vary from ~10 to 25 nm, band gap Eg decreases from 1.9 to 1.5 eV. For Si nanolayers, Eg is ~1.1–1.2 eV

Abstract The results of a study of the hydrophobic properties of a ZnO coating with different morphologies of the surface are presented. It is shown that the Wenzel state is implemented for the case of samples of ZnO with nanoscale surface roughness, while the Cassie state is implemented for microstructured samples. A superhydrophobic state with a contact angle of 151° and work of adhesion of 8.82

Abstract Isoperiodic GaxIn1 – xSbyAszP1 – y – z/InP heterostructures for the operation at a wavelength of 1.06–1.60 μm are obtained using the method of zone crystallization with a temperature gradient. An absolute spectral sensitivity of about 0.59 A/W and a response time of about 10 ns are achieved. The threshold sensitivity of the created photodiodes is in the range of 2 × 10–10–5 × 10–11 W at a

Abstract The viscosity of a rarefied gas in nanochannels under normal conditions is studied. The viscosity coefficient is calculated from the Green–Kubo formula using the stochastic molecular method. The interaction of gas molecules with the wall is described by the specular, diffuse, or specular-diffuse laws. Gas temperature and channel height are varied. It is shown that the viscosity in the nanochannel

Abstract An approximate analytic equation is derived that describes the law of elongation of a semiconductor nanowire (NW) growing via the vapor–liquid–solid (VLS) mechanism in a substrate plane. Various growth regimes are theoretically analyzed as dependent on NW radius R and epitaxial deposition conditions. It is established that the growth rate of planar NWs can be controlled either by the Gibbs–Thomson

Abstract The first investigation devoted to experimental modeling of the lift of dust particles by shock wave over a target surface has been performed on the Saturn setup for studying the interaction of laser radiation with a porous chondritic target surface bearing finely dispersed talc particles. Results of experimental modeling can be used to describe the lift of dust particles from the zones of