11 Works

Elasticity of thin dilatational disk in an isotropic half-space

T. Nguyen Van, A.L. Kolesnikova & A.E. Romanov
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...

Model for the formation of GaAs-Au axial nanowire heterostructures under flash lamp annealing

Vladimir G. Dubrovskii
Semiconductor-metal nanowire heterostructures have attracted a particular interest over the last decade. However, they often suffer from low interface and crystalline quality. Here, we present a model for the formation of GaAs-Au axial nanowire heterostructures from GaAs/Au core-shell nanowires encapsulated into SiO2 under flash lamp annealing, as described in the previous work. The model reveals the basic mechanism and establishes the main control parameters of the process which enable high quality GaAs-Au heterostructures. It can...

Pair interaction of coaxial circular prismatic dislocation loops in elastic solids with spherical surfaces

S.A. Krasnitckii, A.M. Smirnov & M.Yu. Gutkin
In the present work, the pair interaction of coaxial circular prismatic dislocation loops (PDLs) arbitrary placed in elastic solids with free spherical surfaces is considered. The analytical solutions for the pair interaction energies of PDLs in an elastic sphere, an elastic medium with a spherical pore and a spherical layer are given in the form of double power series and illustrated by energy maps built in the space of the normalized PDL radii and axial...

Multi-step dilatational inclusion in an elastically isotropic cylinder

A.L. Kolesnikova , A.E. Romanov, M. Yu. Gutkin & V.E. Bougrov
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...

On cracking in thick GaN layers grown on sapphire substrates

M.G. Mynbaeva, A.A. Sitnikova, A.N. Smirnov, K.D. Mynbaev, H. Lipsanen, A.V. Kremleva, D.A. Bauman, V.E. Bougrov & A.E. Romanov
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.

Growth of thick gallium oxide on the various substrates by halide vapor phase epitaxy

A.V. Kremleva, Sh.Sh. Sharofidinov, A.M. Smirnov, E. Podlesnov, M.V. Dorogov, M.A. Odnoblyudov, V.E. Bougrov & A.E. Romanov

Polycrystalline films of phosphors Cd(1-x-y-z) (CuyAgz) ZnxS on the silicon substrate with the silicon carbide buffer layer: structure and properties

N.M. Sergeeva, S.P. Bogdanov & A.V. Redkov
Polycrystalline phosphor film Cd(1-x-y-z) (CuyAgz) ZnxS was grown on the surface of the Si/nano-SiC heterostructure obtained by the unique method of substitution of atoms. The structural, phonon (vibrational) properties of the film, as well as its morphology were studied. X-ray phase analysis (XRD) showed that the phase composition is represented by a matrix of solid solution of cubic syngony and impurity phases formed during precipitation: sodium sulfate (Na2SO4) of orthorhombic syngony and sodium cadmium sulfide...

Structural characterization of bulk (AlXGa1-X)2O3 crystals grown by the Czochralski method

A.V. Kremleva, D.A. Kirilenko, I.G. Smirnova, V.E. Bougrov & A.E. Romanov
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...

Axial misfit stress relaxation in core-shell nanowires with hexagonal core via nucleation of rectangular prismatic dislocation loops

S.A. Krasnitckii, A.M. Smirnov, K.D. Mynbaev, L.V. Zhigilei & M.Yu. Gutkin
A theoretical model of axial misfit stress relaxation in core-shell nanowires with hexagonal cross section of the core through the nucleation of prismatic dislocation loops is suggested. Different nucleation sites of the loops in core-shell nanowires are considered. The energy change caused by the loop nucleation is calculated. The critical condition for the onset of the loops is given and analyzed in detail. The most favorable sites in nanowires and the optimal loop shape are...

Czochralski grown (AlxGa1-x)2O3 crystals with variable Al content

P.N. Butenko, D.I. Panov, A.V. Kremleva, D.A. Zakgeim, A.V. Nashchekin, I.G. Smirnova, D.A. Bauman, A.E. Romanov & V.E. Bougrov
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...


V.V. Kaminskii, Y.V. Lyubimova & A.E. Romanov
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...

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  • ITMO University
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  • Peter the Great St. Petersburg Polytechnic University
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  • St. Petersburg State Technological Institute