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The temperature and time dependences of the concentration of kinks on the SA and SB steps perpendicular to the upper-terrace dimer rows on the Si(100) surface with an inclination of 0.5° are established. The numbers of step kinks are determined from atomic-resolution scanning tunneling microscopy images of the stepped Si(100) surface. It is shown that the temperature dependence of the number of kinks has a minimum at 650°С. It is suggested that, at low temperatures, the steps are intensively smoothed (step kinks vanish), while at high temperatures, the step-destruction process (formation of a great number of step kinks) is more intensive. The step smoothing and destruction processes include a sequence of atom and dimer elementary acts. As the annealing time increases, the kink concentration decreases and takes a constant value. The equilibrium step-kink concentration is shown to be determined by the surface annealing temperature and time. [ABSTRACT FROM AUTHOR]

The possibility of forming a strained pseudomorphous quantum well (QW) consisting of a InxGa1 –xAsyP1 –y quaternary alloy upon the deposition of InAs onto the surface of an epitaxial GaP/Si layer with a developed relief is demonstrated. The QW is studied by means of transmission electron microscopy and steady-state photoluminescence spectroscopy. The formation of two QW segments different in width and composition of the InxGa1 –xAsyP1 –y alloy is observed; in this case, an increase in the QW width is accompanied by a decrease in the content of In and As atoms. The lateral dimensions of the QW segments are no smaller than 20 nm. The QW segments correspond to two different low-temperature photoluminescence bands. The experimentally observed phenomena are interpreted on the assumption of transformation of the surface under the action of elastic strains during heteroepitaxy of InAs on the terraced GaP surface. [ABSTRACT FROM AUTHOR]

GaSb films are grown by molecular-beam epitaxy using AlSb/As/Si transition layers on vicinal Si(001) substrates miscuted by 6° in (111) plane direction. The effect of GaSb films crystallographic orientation on their structural properties and surface morphology is investigated. It is found that the GaSb(00 )/Si films are characterized by better structural perfection, a lower concentration of point defects, as well as a more planar and isotropic surface morphology as compared with the GaSb(001) films. The possible cause for the observed othernesses between the GaSb films with different orientations is an increased density of antiphase domains in GaSb(001) films. The morphological features of the grown films are caused mainly by the edges of terraces and, to a lesser extent, by anisotropy of the incorporation of Ga adatoms into the edges of the terraces. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: New-onset atrial fibrillation (NOAF), a common complication of acute ST-segment elevation myocardial infarction (STEMI), is associated with a poor prognosis. Several clinical and laboratory parameters are reported to be associated with NOAF in patients with STEMI. The aim of the present study was to evaluate the predictive value of plasma B‑type natriuretic peptide (BNP) levels for NOAF development and long-term prognosis in STEMI patients undergoing primary percutaneous coronary intervention (pPCI).Patients and methods: We retrospectively enrolled 1,928 patients with STEMI who underwent pPCI. After applying exclusion criteria, 1,057 patients were retained in the final study population. Patients with NOAF were compared with patients without NOAF in the entire study population and in a matched group.Results: Patients with NOAF had a significantly higher average plasma BNP level (161 pg/ml, range: 72.3-432) than patients without NOAF in the study population (70.7 pg/ml, range: 70-129; p < 0.001) and in the matched group (104.6 pg/ml, range: 47.2-234.5; p = 0.014). Furthermore, the plasma BNP level was found to be an independent predictor of NOAF development (odds ratio [OR]: 1.003; 95% confidence interval [CI]: 1.000-1.005; p = 0.034) and mortality in the long-term follow-up (OR: 1.004; 95% CI: 1.002-1.006; p < 0.001).Conclusion: The present study found that a high plasma BNP level was significantly associated with NOAF development in STEMI patients, and was an independent predictor of NOAF development and all-cause mortality during long-term follow-up, regardless of other NOAF risk factors. [ABSTRACT FROM AUTHOR]

Nucleation of Ge islands on a stepped Si(100) surface is studied. It is shown by diffraction of fast electrons that at a temperature of 600°C, constant flux of Si, and deposition rate of 0.652 Å/s, a series of the 1×2 superstructure reflections completely disappears, if the Si (100) substrate deviated by an angle of 0.35° to the (111) face is preliminarily heated to 1000°C. The disappearance of the 1×2 superstructure reflexes is due to the transition from the surface with monoatomic steps to that with diatomic ones. Investigations of the Ge islands’ growth were carried out on the Si(100) surface preliminarily annealed at temperatures of 800 and 1000°C. It is shown that the islands tend to nucleate at the step edges. [ABSTRACT FROM AUTHOR]

The temperature and composition dependences of the critical thickness of the 2D-3D transition for a GeSiSn film on Si(100) have been studied. The regularities of the formation of multilayer structures with pseudomorphic GeSiSn layers directly on a Si substrate, without relaxed buffer layers, were investigated for the first time. The possibility of forming multilayer structures based on pseudomorphic GeSiSn layers has been shown and the lattice parameters have been determined using transmission electron microscopy. The grown structures demonstrate photoluminescence for Sn contents from 3.5 to 5% in GeSiSn layers. [ABSTRACT FROM AUTHOR]

Copyright of Herz is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Herz is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new technology of visualization and diagnostics of transparent media with gradient inhomogeneities is described. This technology is called three-dimensional laser diffractometry; it is based on refraction of spatially structured laser radiation and digital recording and processing of two-dimensional (in transmitted light) or three-dimensional (in scattered light) refractive patterns. Results of computer simulations of three-dimensional refractive patterns (3D refractograms) for spherically and plane layered media are presented. A setup for observation of 3D refractograms in scattered light is schematically described, the method of obtaining refractograms from experimental two-dimensional refractive patterns is presented, and examples of computer processing of experimental data are given. [ABSTRACT FROM AUTHOR]