A. L. Vasil’ev

Investigation of the structural conditionality for changes in physical properties of K3H(SO4)2 crystals

AbstractWith the aim of elucidating the nature of anomalies in the physical properties of K3H(SO4)2 crystals that arise as the temperature grows, the dielectric and optical properties of the crystals are studied, an X-ray diffraction analysis of single-crystal and polycrystalline specimens are performed, and the morphology and chemical composition are studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. As a result of the studies performed, a phase transition from the phase with the monoclinic symmetry (space group C2/c) to the phase with the trigonal symmetry (space group R

Structural and electrical properties of quantum wells with nanoscale InAs inserts in InyAl1 − yAs/InxGa1 − xAs heterostructures on InP substrates

\bar 3

Growth of crystalline ZnO films on the nitridated (0001) sapphire surface

m) is found in a number of K3H(SO4)2 specimens at a temperature of ≈457 K, the responsibility of the dynamically disordered hydrogen-bond system for the rise of high proton conductivity in the high-temperature phases of the crystals of this family is confirmed, and data on the solid-phase reactions proceeding at high temperatures are obtained.

Single-crystal structure study of iron chalcogenides Fe1 + δTe1 − xSx

The results are presented of a computer and physical simulation concerned with the estimation of CMOS-circuit susceptibility to single-event latchup. A laser-simulation procedure is proposed and tested in which only the most sensitive areas are irradiated. The estimates are found to agree with the measurements.

Electron microscopy of phase and structural transformations in soft magnetic nanocrystalline Fe-Zr-N films

A complex study of the effect ofintroduction of nanoscale InAs inserts of different thicknesses into an In0.53Ga0.47As quantum well on the electrical properties and structural features of In0.50Al0.50As/In0.53Ga0.47As/In0.50Al0.50As nanoheterostructures with bilateral δ-Si doping grown on InP substrates has been performed. The layers of nanoheterostructures with a weak lattice mismatch are found to be equally (cube-on-cube) oriented. The introduction of a nanoscale InAs insert leads to an increase in mobility. At an insert thickness of about 1.8 nm, the effect of increasing mobility is saturated due to structural deterioration. The segregation of the second (apparently, wurtzite) phase is revealed; this process, as well as the formation of other defects in the nanoheterostructure layers, is due to local strains caused by variations of the indium content in the layers.

Specific features of sample preparation from amorphous aluminum alloys for transmission electron microscopy

Multilayer structures composed of four porous bilayers have been studied by high-resolution X-ray diffraction using synchrotron radiation, and the photoluminescence of these structures has been investigated at 4 K. The porous structures were formed by anodic oxidation of InP(001) substrates in aqueous HCl solution. The structural parameters of the sublayers were varied by changing the electrochemical etching mode (potentiostatic/galvanostatic). The X-ray scattering intensity maps near the InP 004 reflection are obtained. A model for scattering from such systems is proposed based on the statistical dynamical diffraction theory. Theoretical scattering maps have been fitted to the experimental ones. It is shown that a mathematical analysis of the scattering intensity maps makes it possible to determine the structural parameters of sublayers. The reconstructed parameters (thickness, strain, and porosity of sublayers and the shape and arrangement of pores) are in satisfactory agreement with the scanning electron microscopy data.

Application of X-ray diffraction methods in the study of micrometer-sized porous Si layers

The surface morphology and structure of (0001) sapphire substrates subjected to thermochemical nitridation in a mixture of N2, СО, and Н2 gases are investigated by electron and probe microscopy and X-ray and electron diffraction. It is shown that an aluminum nitride layer is formed on the substrate surface and heteroepitaxial ZnO films deposited onto such substrates by magnetron sputtering have a higher quality when compared with films grown on sapphire.

Study of one-dimensional crystal@single wall carbon nanotube nanocomposites using atomic resolution scanning transmission electron microscopy

Single crystals of iron chalcogenides Fe1 + δTe1 − xSx (x = 0, 0.09, and 0.1) were studied by scanning, transmission, and scanning transmission electron microscopy. In addition, a sample with x = 0 was studied by X-ray diffraction. The Te-site disorder observed in Fe1 + δ samples is, apparently, assigned to the incorporation of superstoichiometric iron Fe2 into the structure. The Fe1 atoms were found to be displaced from their ideal positions, which can only partially be attributed to electro-optical effects. The replacement of Te atoms by S in Fe1 + δTe1 − xSx crystals gives rise to domains with ordered S atoms in some regions of the single crystal, resulting in the formation of a 2 × 1 or 2 × 2 superstructure.