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In this article, the solution to the elasticity boundary-value problem for an infinitesimally thin dilatational disk (ITDD) embedded in an elastically isotropic half-space is presented. The plane of the disk is parallel to the free surface. To solve the boundary value problem, the method of virtual defects is used. The image (mirror) ITDD and radial Somigliana dislocation loops (RSDLs), distributed continuously over the free surface coaxially with the ITDD, are chosen as virtual defects. The ITDD displacements, strains, and stresses are represented in the form of the sums of the Lipschitz - Hankel integrals. It is shown that the elastic field of the ITDD disk is distorted near the free surface and possesses nonzero dilatation and hydrostatic stress. Numerical estimates of dilatation are given and its influence on some characteristics of semiconductors is briefly discussed.

We consider an elastic inclusion in a cylinder with isotropic materials properties. The inclusion possesses a multi-step dependence of the dilatational eigenstrain along the cylinder axis. Basing on the solution for the trace of the stress tensor of the dilatational inclusion with sharp boundaries (single-step inclusion) the stored elastic energy of the multi-step inclusion is determined and analyzed. Then, the found analytical solution for the inclusion energy is used to investigate the energy properties of the transition region between the cylinder domains with a constant level of dilatational eigenstrain. The application of the obtained results to the relevant physical problems of mechanical behavior of hybrid nanodisk/nanowire (ND/NW) semiconductor heterostructures is discussed.

In the present work, using the method of a composite piezoelectric oscillator at a frequency of 99-102 kHz, polycrystalline magnesium was studied under two types of treatment: deformation and subsequent annealing. The influence of these types of treatments on changes in the dislocation density and such an important structurally sensitive parameter as the dynamic Young's modulus has been established. The values of micro-yield stress are determined. With a longitudinal deformation of 1.7%, at the strain amplitude of 5×10-6 , its value decreased from 2.9 MPa to 1.7 MPa; after annealing at 400 °C, it increased to 5.8 MPa.

Self-organization mechanisms promoting elimination of cracks in thick GaN layers grown on sapphire substrates are considered on the basis of the experimental results on the fabrication of the layers by Hydride Vapor-Phase Epitaxy on MOCVD-grown GaN/Al2O3 templates. The obtained data support the supposition on the closure of tensile stress-related cracks via diffusion processes and demonstrate the strong contribution of bulk diffusion in addition to surface diffusion discussed earlier.

The elastic interaction of quantum disks (QDs) in a nanowire (NW), i. e., in a hybrid QD/NW structure with sharp heterointerfaces, is considered for the first time. Within the framework of the defect micromechanics approach, the energy of QD pair interaction is established and it is demonstrated that for QDs with a lattice misfit of the same sign, a zone of attraction to each other appears, depending on the ratio of the QD axial size to the NW radius. The discovered effect should be taken into account when choosing the modes of formation of hybrid QD/NW structures and in models explaining their properties. Keywords: nanowire (NW), quantum disk (QD), QD/NW hybrid structure, lattice mismatch, dilatation inclusion, strain energy.

We propose a technuque of liquid-phase growth of (AlxGa1-x)2O3 crystals with variable and controlled Al content in them. When using the Czochralski growth process Ga2O3 melt was dosed by sapphire seed. By applying of the special growth zone and the regulating the process parameters, a series of crystal samples with Al content varying from 0.51 to 4.68 % at. was obtained. In addition to the standard setting of the geometry and weight of the crystals using the process parameters, with an increase of the Al content in the melt, it is possible to control the color, transparency and crystallinity of the fabricated samples.

The paper presents the results of potassium-lithium-borate glass containing copper ions investigations. The glass was irradiated by 1.25 MeV gamma rays. The dose of radiation was 360 Gy. The exciting of the irradiated glass at 360 nm led to the long-wavelength photoluminescence band shift from 635 nm to 671 nm in comparison with non-irradiated glass. A new luminescence band at 685 nm also appeared for excitation wavelength 405 nm in the irradiated glass. It has been assumed that the luminescence band in glass at 671 nm – 685 nm corresponds to the luminescence of copper ions in the modified environment of the first coordination sphere. Copper-containing luminescent structures in borate glass with the luminescence maximum at 671-685 nm have been obtained for the first time. For the detailed study of these luminescent centers properties, thorough study of the structural variations in the gamma rays irradiated glass is required.

Results of structural characterization of (AlxGa1-x)2O3 single crystals grown from the melt with Al content x up to 0.04 are presented. Bulk (AlxGa1-x)2O3 crystals were grown by exploring the Czochralski method [1]. Transmission electron microscopy (TEM) was used to investigate defect structure of the material with various composition, X-ray diffractometry was used to measure Al content x, to inspect crystallography of the growth facets and to characterize the structure quality of the samples. Possible types of defects were identified in the samples with various composition including single dislocations, cracks, and low-angle misorientation block boundaries. Measured full-width at half-maximum (FWHM) of rocking curves of 200" confirmed high quality of the grown crystals.