The photosensitive germanium layers on a silicon substrate have been formed by molecular beam epitaxy. The structural, optical, and photovoltaic characteristics of the films have been investigated. The data obtained confirm the possibility of using the developed Ge on Si heterostructures for fabrication of photodetectors in the spectral range of 1.3–1.55 μ m

Методом молекулярно-лучевой эпитаксии сформированы фоточувствительные слои германия на кремниевой подложке. Исследованы структурные, оптические и фотоэлектрические характеристики плёнок. Полученные данные подтверждают возможность использования изготовленных гетероструктур Ge на Si для создания фотодетекторов спектрального диапазона 1,3-1,55 мкм. Photosensitive germanium layers on a silicon substrate have been formed by molecular beam epitaxy. The structural, optical and photovoltaic characteristics of the films have been investigated. The data obtained confirm the possibility of utilizing the developed Ge-on-Si heterostructures for the fabrication of photodetectors in the spectral range of 1.3-1.55 μm.

The crystal structures of two ZnGeP2 crystals grown by the Vertical Bridgman method in different furnaces were compared. The furnace tube diameter was 70 mm for the first crystal and 130 mm - for the second one. The diameter of both crystals was 30 mm. The radial temperature profiles of the furnaces show different curvatures in the growth zone. For the first crystal the profile was slightly concave, whereas, for the second one, it was flat. The structure was analyzed by X-ray diffractometry and topography methods. In the first crystal, the dislocation density changed from 10(2) cm(-2) in the initial growth region of the sample to 10(4) cm(-2) at the last-to-freeze end. Low-angle grain boundaries were observed. The second crystal contained only single dislocations. Both crystals showed growth striae. After thermal annealing (both crystals were treated under identical conditions), the second crystal showed a much better optical transparency than the first one.

A method is proposed for determining petroleum products (PPs) in soil of natural moisture content by IR spectrometry. The results obtained by the proposed IR spectrometric procedure with measuring the absorbance of an extract of oil products from the soil with Freon 113 are compared with those obtained by the standard procedure. The determination of oil products in soils according to GOST R 54039-2010 and RD 52.18.575-96 does not permit the assessment of the concentration of light petroleum products because a significant part of them is lost during drying samples at the stage of sample preparation. The proposed method significantly increases the reliability of the quantification of petroleum products in soils, because the measurements are carried out at the natural moisture content of the samples, corresponding to their moisture content at the time of removal from the bedding horizon.

The article describes the technology for synthesis of full functional check programs for train traffic management systems. Algorithms for synthesis of a full set of safety functions and synthesis of minimized set of safety functions are also presented.

Национальный технический университет «Харьковский политехнический институт» УТилизация рТУТных ТермОмеТрОВ аннотация.В данной статье изучены и проанализированы проблемы утилизации и ликвидации ртутьсодержащих приборов.Охарактеризованы три наиболее распространенных способа утилизации ртутных термометром.Рассматриваются вопросы негативного влияния ртутных паров на окружающую природную среду и на здоровье человека.Детально описаны основные виды отравления парами ртути.Наиболее опасными являются острые отравления ртутью

The effect of a substrate misorientation degree from a singular face on the composition and morphology of layers of InAsxSb1 –x solid solutions obtained by molecular-beam epitaxy on a GaAs surface has been investigated. The substrates of GaAs wafers with the orientation (100) misoriented in the direction [110] by 0°, 1°, 2°, and 5° are used. The heterostructures are grown at temperatures of 310°C and 380°C (respectively, the lower and upper boundaries of the temperature range in which structurally perfect InAsxSb1 –x films form). The effect of the molecular form of arsenic (As2 or As4) on the composition of the layers is studied. The composition and structural properties are investigated using high-resolution X-ray diffractometry (HRXRD) and atomic-force microscopy (AFM). It is established that, in the series of misorientation angles 0° → 5°, the arsenic fraction x increases consecutively when using fluxes of both As2 and As4 molecules. With the As2 molecular flux, the fraction x increases only a little (1.05 times) with increasing degree of misorientation, while, when using the As4 flux, the increase in x is 1.75 times. An increase in the growth temperature leads to growth in the arsenic fraction in the solid solution. The surface morphology improves with an increasing degree of misorientation at a low growth temperature and degrades at a high temperature.

The influence of substrate misorientation degree on the composition and morphology of layers during molecular-beam epitaxy of InAsxSb1−x solid solutions on the GaAs surface was studied. The GaAs wafers with orientation (001), which were miscuted in the [110] direction by 0, 1, 2 and 5◦, were used as substrates. The growth of heterostructures was performed for temperatures of 310◦C and 380◦C (lower and upper boundaries for the temperature range of structurally perfect InAsx Sb1−x films formation, respectively). The influence of the arsenic molecular form (As2 or As4) on the composition of layers was studied. Studies of composition and structural properties were carried out using high-resolution X-ray diffractometry (HRXRD) and atomic force microscopy (AFM). It was established that in the series of misorientation from 0 to 5◦ the arsenic fraction x increases consecutively with the use of both flux of As2 and flux of As4 molecules. When the flux of As2 molecules is used, the fraction x increases insignificantly (in 1.05 times) with a rise of misorientation degree, but when using As4 molecules, x increases in 1.75 times. The increase of the growth temperature leads to the rise of the arsenic fraction in the solid solution. The morphology of the surface improves during increasing of misorientation degree at a low growth temperature and degrades at high temperatures.

AbstractAn approach to instant testing of epitaxial films with a sharp decrease in the threading dislocation density is proposed. High-resolution X-ray diffractometry, including reciprocal space mapping, has been used. The structure of GaAs/Si(001) heterosystems with low-temperature GaAs layers has been analyzed. A decrease in the density of threading dislocations in the GaAs film with the formation of a small-angle boundary has been detected.

A theoretical analysis of the process of introducing misfit dislocations into a semiconductor heterostructure with a (013) interface is performed by assuming conditions of quasi-equilibrium process. The mechanism of generation is established for those misfit dislocations, which do not meet the requirement of minimum critical film thickness. The calculations are performed on the basis of the force balance model and allow for the shear stress field in the film and the type of the screw dislocation component.

An approach to instant testing of epitaxial films with a sharp decrease in the threading dislocation density is proposed. High-resolution X-ray diffractometry, including reciprocal space mapping, has been used. The structure of GaAs/Si(001) heterosystems with low-temperature GaAs layers has been analyzed. A decrease in the density of threading dislocations in the GaAs film with the formation of a small-angle boundary has been detected.

The results of X-ray transmission topography and diffraction analysis of a ZnGeP 2 single crystal grown by the vertical Bridgman method in the [001] direction are presented and discussed. The FWHM of rocking curves over a large area of a (100) longitudinal slice is about 12′′, which is indicative of the high quality of the examined sample. Glow discharge mass spectrometry does not show significant content of foreign chemical elements. X-ray topography reveals growth striations and dislocations. The predominant defects are single dislocations and their pile-ups. Near to the growth-axis region, curved dislocation bundles passing through the entire crystal are observed, on which precipitates are formed. In the initial part of the crystal, dislocations are located chaotically, while towards the middle of the sample they are aligned along the growth striae. In the final part of the crystal, the dislocation density increases.

A method of the IR spectrometric determination of weight fractions of oil and gas condensate in the production of oil and gas condensate wells is proposed. The features of infrared spectra of the integrated absorbance of hydrocarbon solutions, recorded using a Fourier-transform IR spectrometer and an IKAR-3 scanning IR spectrometer, are discussed.

Dislocation structure of the Ge single crystals grown by Czochralski method with low thermal gradient has been studied. The selective etching technique and the X-Ray transmission and reflection topography were used. Clearly defined non-uniform dislocation distribution over the crystal cross - section is revealed. Helical dislocations and sets of prismatic dislocation loops are registered. Helical dislocations perpendicular to the ingot axis are situated near the boundary between the regions with low and high dislocation densities (102 and 103 cm−2, respectively). Their length can be as much as several millimeters. Dislocation formations lying at a 35.3° to the crystal axis along <110> directions are also observed. These formations have the shape of prism confined by {111} planes.

The structure of GaP films grown by molecular-beam epitaxy on vicinal Si(1113) substrates has been studied by X-ray diffraction. It is established that the crystalline lattice of a pseudomorphic film rotates about the <110> axis toward increasing deviation from the singular orientation, while the subsequent relaxation leads to rotation in the opposite direction. This is valid for the films of both (001) and (001̄) polarities. Differences between the surface morphologies of relaxed and pseudomorphic GaP films are revealed.

С использованием метода рентгеновской дифрактометрии исследована структура пленок GaP, выращенных методом молекулярно-лучевой эпитаксии на вицинальных подложках Si(1113). Установлено, что кристаллическая решетка псевдоморфной пленки поворачивается вокруг < 110> в сторону увеличения отклонения от сингулярной ориентации. В процессе релаксации происходит поворот в противоположную сторону. Это справедливо для пленок обеих полярностей: (001) и (001). Установлены отличия морфологии поверхности релаксированной и псевдоморфной пленок GaP. DOI: 10.21883/PJTF.2017.04.44299.16494

A significant dependence of the strain state of GaAs film lattice grown by molecular−beam epitaxy (MBE) on the nucleation method of early GaP buffer layers (50 nm) on the vicinal substrate Si(001) 4° around the <011> axis was discovered. GaP growth started layer−by−layer with a gallium or a phosphorus sublayer. If GaP nucleated with a gallium sublayer, the GaAs film has a significant lattice rotation around the <011> axis. If the buffer starts forming with a phosphorus layer the GaAs film evidently rotates around the <001> axis. The film relaxation degree ex- ceeds 100%, and the film is in a laterally strained state. Analysis was carried out using the triclinic distortion model. A reciprocal space scattering map was obtained using X−ray diffraction in a three−axis low resolution setup. The map clearly shows that the GaAs film lattice is rotated.

The influence of As molecular form on the composition and crystalline properties of InAsxSb1-x solid solutions with MBE has been experimentally investigated. A series of samples has been grown at different growth temperatures. The grown samples were studied with the HRXRD and TEM methods. The incorporation coefficient of As4 and As2 molecules were determined at different growth temperatures. It has been found that the incorporation coefficient of As4 much more dependent on growth temperature compared to As2. It has been found that at a low growth temperature a step-like increase of Sb fraction in an InAsxSb1-x film leads to a decrease of threading dislocations density in a layer with a smaller x.