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The possibility of controlling the curvature of the profiles of the surface of X-ray optical elements using single-crystal SiO2(011) plates of rectangular and trapezoidal shapes was studied. In bending regulators (BRs) of various forms, the active element was a piezoelectric bimorph glued to a single-crystal plate. Experimental and calculated data of changes in the profile and radius of curvature of the surface of the used plate are given. The influence of the forms of the components of the bending regulator is shown on the initial profile and surface curvature of X-ray optical elements.

Spin light-emitting diodes based on InGaAs/GaAs heterostructures with a CoPt ferromagnetic injector were fabricated. It was demonstrated that the processing of these structures in selenium vapor prior to the deposition of a CoPt contact provides an opportunity to enhance the circular polarization degree of diode emission. The observed increase in the polarization degree is attributed to the suppression of spin relaxation at the metal/semiconductor interface due to surface passivation and a reduction in the density of surface electron states as a result of processing in selenium vapor.

A bulk nanostructured material based on oxidized silicon nanopowder was fabricated using a spark plasma sintering technique. Structural investigations revealed that this material has the composition of ∼14 nm core Si granules inside an SiO2 shell. Photoluminescence measurements have shown that the emission spectra lie in the energy range of 0.6–1.1 eV, which is not typical of the emissions of the Si/SiO2 nanostructures reported in numerous papers. This result can be explained by the formation of energy states in the bandgap and the participation of these states in both electronic transport and photoluminescence emission. Annealing of the sample leads to a decrease in defect density, which in turn leads to quenching of the 0.6–1.1 eV photoluminescence. In this case ∼1.13 eV inter-band transitions in the Si core start to play a dominant role in radiative recombination. Thus, the possibility of controlling the photoluminescence emission over a broad wavelength range was demonstrated.

We report on the investigation of the growth defect formation in the GeSn/Ge/Si(001) epitaxial layers grown by hot wire chemical vapor deposition of Ge with simultaneous co-evaporation of Sn from an effusion cell. The nucleation of α -Sn nanoinclusions in the course of the growth process was found to be the main mechanism of elastic strain relaxation in the Ge 1 - x Sn x epitaxial layers at x > 2.5 % as opposed to the misfit dislocation formation at the GeSn/Ge interfaces. Also, β -Sn nanoislands nucleating on the surface of the GeSn epitaxial layers with increased Sn concentration due to Sn segregation were identified by confocal Raman microscopy.

The paper presents a method for manufacturing mechanically strong sputtering composite targets containing the phase of the Co2FeSi or Co2MnSi Heusler alloy of the stoichiometric composition, which can be used for fabrication of spin electronic devices by high-frequency magnetron deposition and pulsed laser deposition of thin films.

The possibility of forming specified surface profiles of X-ray optics elements (XROEs) for focusing and collimation of X-ray beams is considered. It is shown that the curvature of these elements can be controlled by varying the temperature of curvature regulator on the surface of which they are fixed in place. Using the calculated and experimental data, it is shown that inhomogeneity of the thickness of the curvature controller substrate influences the curvature and profile of XROEs. In particular, the possibility of obtaining parabolic and elliptical surface profiles of XROEs, which can be used to create adaptive X-ray optics elements for two-dimensional focusing and collimation of an X-ray beam is demonstrated.

Synthesis and modification of gallium oxide as a wide-bandgap semiconductor is a topical task in the fields of power electronics, UV detectors, gas sensors, telecommunication. In the present work, the Ga2O3 films deposited on sapphire substrates by magnetron sputtering have been studied. The influence of deposition parameters and subsequent annealing on the structure and optical properties of the synthesized films is analyzed. Ion doping of magnetron-deposited films with silicon is carried out by the ion implantation method. It is shown by the Raman scattering and optical transmission spectroscopy that ion irradiation leads to the disordering of the crystal structure, but subsequent annealing results in a partial recovery of the structure. Hall-effect measurements for irradiated and then annealed films do not reveal the formation of a conducting layer. Apparently, this is due to the fact that the main contribution to the resistance is made by grain boundaries in the magnetron-deposited films.

The possibility of interactively controlling the surface curvature of a single-crystal Si(100) plate used as a diffraction element is investigated. The initial component-surface profile is specified by the substrate shape, parameters of the adhesive, and the temperature of its adhesion to the substrate. The results of calculating the changes in surface profile and its curvature radius are presented.

We investigate the possibility of the generation of arrays of single-crystal islands with small angular dispersion in order to use them as active media for solving the problems of controlling the parameters of X-ray beams. Using the example of a three-layer structure of substrate–adhesive–single-crystal wafer, we experimentally demonstrate the possibility of controlling the profile of diffractive elements by changing its temperature. It is revealed that the main reason for island misorientation is shrinkage of the adhesive material upon its solidification. Another reason for misorientation is softening the adhesive, which occurs upon plasma-chemical etching of the wafer. These effects can be eliminated by changing the temperature of attaching the wafer to the substrate surface and by using a nonsoftening adhesive. The temperature of attaching a single-crystal wafer to the substrate is calculated from the shrinkage coefficients of the adhesive and the thermal- expansion coefficients of the components of the structure.

Multilayer structures on the basis of n-type (In,Fe)Sb and p-type (Ga,Fe)Sb diluted magnetic semiconductors (DMS) along with separate (In,Fe)Sb and (Ga,Fe)Sb layers were fabricated on GaAs substrates by pulsed laser sputtering of InSb, GaAs, GaSb, Sb and Fe targets in a vacuum. Transmission electron microscopy and energy-dispersive x-ray spectroscopy reveal a strong dependence of the phase composition of the (In,Fe)Sb compound on the growth temperature. An increase of the latter from 220 °C to 300 °C leads to a coalescence of Fe atoms and formation of a secondary crystalline phase in the (In,Fe)Sb layer with a total Fe content of ≈ 10 at. %. At the same time, the Ga0.8Fe0.2Sb layers obtained at 220 °C and 300 °C are single-phase. The separate In0.8Fe0.2Sb and Ga0.8Fe0.2Sb layers grown on i-GaAs at 220 °C are DMS with Curie temperatures of ≈ 190 K and 170 K, respectively. The three-layer p-i-n diode (In,Fe)Sb/GaAs/(Ga,Fe)Sb structure grown on a GaAs substrate at 220 °C with a Fe content of 10 ± 1 at. % in the single-phase (In,Fe)Sb and (Ga,Fe)Sb layers has a rather high crystalline quality and can be considered as a prototype of a bipolar spintronic device based on Fe-doped III-V semiconductors.

The technology of the growth of Si, Ge, and Si1–xGex layers by molecular-beam epitaxy with the use of a sublimation source of monoisotopic 30Si or 28Si and/or gas sources of monogermane 74GeH4 is demonstrated. All of the epitaxial layers are of high crystal quality. The secondary-ion mass spectroscopy data and Raman data suggest the high isotopic purity and structural perfection of the 30Si, 28Si, 74Ge, and 30Si1–x74Gex layers. The 30Si layers doped with Er exhibit an efficient photoluminescence signal.

We report on growing the p-Ge:Ga/Si(0 0 1) epitaxial layers by hot wire chemical vapor deposition using a solid Ge:Ga sublimation source of Ga. The Ge:Ga layers grown using this doping method were featured by a high crystal quality and full electrical activation of the Ga impurity. The results of the present study demonstrate the prospects of application of the sublimation Ga source for growing the Ge:Ga layers in the Ge/Si(0 0 1) device structures for Si-based electronics and photonics.

The fabrication of photodetectors for the wavelength range of communications λ = 1.3–1.55 µm on the basis of Ge/Si(001) heterostructures with thick (~0.5 µm) Ge layers grown by the hot-wire technique at reduced growth temperatures (350°C) is reported. The single-crystal Ga layers are distinguished by a low density of threading dislocations (~105 cm–2). The photodetectors exhibit a rather high quantum efficiency (~0.05 at λ = 1.5 µm and 300 K) at moderate reverse saturation current densities (~10–2 A cm–2). Thus, it is shown that the hot-wire technique offers promise for the formation of integrated photodetectors for the wavelength range of communications, especially in the case of limitations on the conditions of heat treatments.

The possibility of controlling the dispersion properties of light-absorbing crystals subjected to laser radiation is investigated. The presented experimental and calculation data indicate that the half-width of the diffraction reflection curve of light-absorbing crystal monochromators can be substantially increased.

The design features of the crystal-monochromator module, whose rocking-curve FWHM changes in a predetermined manner under the action of a thermal effect produced by a semiconductor infrared laser on its working surface, are described. The calculated and experimental data on the interactive control of the parameters of the described module’s rocking curve are presented. The possibility of using this module in X-ray topography for obtaining additional information on the actual surface structure of defective crystals is shown.

A new method of microchannel formation in silicone rubber cured by heat in the presence of a platinum catalyst was developed using whiskers of p-aminobenzoic acid. Four types of whiskers with lateral dimensions of 10–20, 50–70, 200–300, and 500–600 µm and lengths of 2–3, 5–10, 10–20, and 20–30 mm, respectively, were grown from hot aqueous solutions. A new method for the manufacture of elastic siloxane rubber samples penetrated by open channels with the size corresponding to the size of whiskers is presented. The materials were studied by optical and atomic force microscopy, powder X-ray diffraction, differential scanning calorimetry, gas chromatography—mass spectrometry, and porosimetry.

The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.

We investigate the possibility of controlling the curvature parameters of parabolic mirrors that are modular elements of two types consisting of a base and thin inserts placed at the opposite side of the work surface. In the first type of modular elements, bending is controlled by the difference in the coefficients of the thermal expansion of the base and inserts. In the second type of elements, the profile is changed by the piezoelectric straining of the inserts under an electric field. A correlation is established between the parameters of modular elements and their surface curvature profile.

Si1 − xGex epilayers have been grown on silicon-on-sapphire structures by molecular beam epitaxy using a sublimation silicon source and gaseous germanium source. Si1 − xGex layers grown directly on sapphire substrates had poorer structural perfection, so Si buffer layers were used in subsequent growth runs. Using X-ray photoelectron spectroscopy, we determined the concentration-depth profiles of Si, Ge, and background impurities across the layers. Varying the Si buffer thickness in the range 50–300 nm was shown to have no effect on the structure of the SiGe layers. Single-crystal SiGe layers were obtained at substrate temperatures in the range 360–410°C. Varying the germanium concentration in the range 5–25% had no effect on the structure of the layers but slightly increased their roughness.

The possibility of developing elements for adaptive X-ray optics on the basis of modular components that consist of a base with a parabolic profile and active elements which are integrated inside is studied. The parameters of the active elements vary in size and are positioned along the surface of the modular components. Calculation data on variations in the profile of the surfaces of modular components, where piezoelectric elements are used as active elements, are presented. It is shown that the profile of the surface of modular elements can be flexibly adjusted based on the parameters of active elements and the electric-field voltage.

The results from experimental investigations on controlling the half-width of the rocking curves of crystals are reported. Control is achieved via the heterogeneous change in the parameters of the crystal lattice caused by the heterogeneous thermal influence of light on the surface of a diffracting crystal. The obtained results could be used to create crystal-monochromators with dynamically operated dispersive properties.

The possibility of increasing the resolution of an X-ray image by changing the relief of the crystal surface is studied. The simulation data for X-ray images obtained by X-ray diffraction from the crystal surface with a columnar relief are presented. It was shown that the resolution of the X-ray image increases more than ten times in the case of the relief of a columnar surface.

Structural perfection of KDP single crystals grown on point seeds by a rapid growth method has been studied by selective etching, UV spectroscopy, x-ray topography, a conoscopic method (to assess anomalous birefringence), rocking-curve analysis, and resistivity measurements. Etching results indicate that the dipyramid growth sectors are less homogeneous. The zonal structure is more pronounced in the peripheral parts of the crystals, that is, in the final stages of rapid growth. In spite of the sectorial and zonal inhomogeneities, the crystals are superior in quality to those prepared by other rapid growth methods.

Simulation of the formation and correction processes of the spatial structure of x-ray diffraction beams (x-ray images) depending on the parameters of the crystal diffraction peak and on the conditions of the temperature deformation field formation at its surface has been performed. Methods for x-ray image contrast improvement are proposed.

Structurally perfect, single-crystal silicon layers have been grown on \((1\overline 1 02)\) sapphire by sublimation-source molecular beam epitaxy. Electron and x-ray diffraction data demonstrate that silicon-on-sapphire epitaxy occurs at substrate temperatures from 550 to 850°C. As the thickness of the layers decreases from 1.0 to 0.2 μm, their structural perfection degrades. In the layers grown at 600°C, the density of nucleation sites in the initial stages of growth is ≃ 5 × 109 cm−2.

The results of experimental investigations of the formation of the spatial structure of x-ray diffraction beams (x-ray images) from the KDP crystal surface under its illumination by a light beam spatially modulated in intensity are presented. A simulation of the x-ray image, depending on the parameters of the diffraction peak of a crystal and on the conditions of the creation of a temperature deformation field at its surface, has been carried out.

The results of studying the birefringence effect on the spatial structure of X-ray images (XRIs) under illumination of the diffracting anisotropic-crystal surface by a spatially modulated light beam are presented. It is shown that the XRI resolution decreases in the case when the temperature field determining the spatial XRI structure is formed by a light beam propogating through the crystal and is absorbed at the interface between the diffraction region and the absorbing coating.

The investigation of bulk single crystals and sputter-deposited films of yttria-stabilized zirconia (YSZ) upon irradiation by gold (Au) ions with an average energy of 160 keV followed by postimplantation annealing revealed peculiarities in the formation of nanocrystalline metal (nc-M) particles in this matrix. In the case of irradiation to small doses (∼5 × 1015 cm−2), the optical absorption spectra of samples showed evidence of the formation of nanoclusters of matrix cations (nc-Zr). In these samples, postimplantation annealing at temperatures ∼700°C and above leads to the formation of nc-Au particles. Local elemental analysis of individual nc-M particles in the YSZ matrix irradiated to a dose of 4 × 1016 cm−2 and annealed at 800°C showed the presence of metal nanoparticles with complex compositions including both implanted Au and matrix Zr atoms.

A possible mechanism for the formation and processing of an x-ray image using a corresponding optical image as a template is considered. The method is based on the thermal influence of light on the x-ray diffraction parameters of an LiNbO3 crystal. A mechanism for the influence of the gradients of the temperature fields formed in the crystal on the x-ray structural parameters of the crystal is proposed. Information which permits the evaluation of some practical aspects of the application of the observed effect in technology is given.

In the present paper, we report on the growing of thick (~0.2-3.0 μm) epitaxial Ge/ Si(100) layers by Hot Wire Chemical Vapor Deposition (HWCVD) at low growth temperatures (350°C). The single crystal epitaxial Ge layers with low threading dislocation density (~105 cm−2) and surface roughness (< 0.5 nm) have been obtained.

The effect of inhomogeneous light-beam-induced heating of a potassium dihydrophosphate (KDP) crystal on the positions of maxima in the patterns of X-ray diffraction has been studied using the characteristic K α1, α2 radiation. This phenomenon can be used in order to decrease aberrations in optical systems.

The effect of nonuniform thermal action of a light beam on the parameters of a diffraction peak for a calcite crystal is studied. It is shown that the spatial intensity distribution in an X-ray beam can be corrected by controlling the thermally induced mismatch between Bragg reflections from local areas in a crystal.