The problem of a rarefied plasma jet emerging from a stationary plasma engine is considered. The consideration is carried out entirely at the kinetic level; namely, the motion of all plasma components is described in terms of distribution functions. The system of kinetic equations should be solved together with Maxwell’s equations. Methods for solving the resulting problem are discussed.

The epitaxial growth technique of InGaAs photodiode structures based on a digital InGaAs/GaAs metamorphic buffer layer by metalorganic chemical vapor deposition has been developed. The spectral dependence of the photocurrent of photodiodes based on the produced structures has a maximum at the 1.16 µm wavelength. The photosensitivity range at 10% of peak is 0.99 - 1.33 µm at room temperature. The current-voltage characteristics in the temperature range 9–300 K were investigated. It is shown that the dark current consists of generation-recombination and tunneling components. The dark current density at room temperature was 8×10 -5 A/cm 2 with a reverse bias of -5 V.

The results of studies of InP/GaAs heterostructures based on metamorphic layers with stepwise and digital changes in composition are presented. The electrophysical characteristics of diodes fabricated based on these structures are compared with diodes grown on matched substrates with InP and GaAs active layers. It is shown that the use of InP/GaAs diodes in a triple balanced mixer made it possible to reduce the local oscillator signal power by a factor of 20.

III–V/Ge/Si(001), III–V/Ge/SOI(001), and III–V/GaAs(001) heterostructures are fabricated and investigated. The Ge buffer layer for the III–V/Ge/Si structure is grown by vapor deposition onto a Si(001) substrate via the decomposition of monogermane on a “hot wire”. In the case of III–V/Ge/SOI, the Ge buffer layer is obtained on a SOI(001) substrate by molecular-beam epitaxy via two-stage growth. The III–V layers are grown by metalorganic chemical-vapor deposition. It is shown that Ge/SOI formed by molecular-beam epitaxy using two-stage growth allows the fabrication of III–V layers that are highly competitive with those formed on Ge/Si in terms of crystalline and optical quality.

GaAs-based heterostructures grown by metalorganic vapor-phase epitaxy on virtual Ge/Si substrates using an AlxGa1-xAs seed layer with different aluminum content x in the solid solution are investigated. The effect of solid solution composition on the density and size of antiphase domains emerging on the sample surface and on the optical properties of the GaAs layer is shown. Si(100) substrates with a small unintentional miscut of 0.7° to [110] were used for growth.

AIIIBV/Ge/Si (001), AIIIBV/Ge/SOI (001), and AIIIBV/GaAs (001) heterostructures were formed and investigated. The Ge buffer layer was produced by the "hot wire" technique on a Si substrate (001) for the AIIIBV/Ge/Si structure. In the case of the AIIIBV/Ge/SOI, the Ge buffer layer was grown on the SOI (001) substrate by molecular beam epitaxy via two-stage growth. The growth of AIIIBV layers were performed by metalorganic chemical vapor deposition. It is shown that the Ge/SOI formed via two-stage growth allows the growth of AIIIBV layers that are not inferior in structural and optical quality to those formed on the Ge/Si.

GaAs-based heterostructures grown by metalorganic vapor-phase epitaxy on virtual Ge/Si substrates using Al x Ga 1 – x As seed layers with different aluminum contents x in solid solution have been investigated. The influence of the x value on the density and sizes of antiphase domains, outcropping onto the sample surface, and optical properties of the GaAs layer is demonstrated. The heterostructures have been grown on (100) substrates with small random off-cut from the nominal crystallographic orientation (0.7° towards [110]).

A previously constructed kinetic model for describing the behavior of a nonideal gas is investigated. The dimensionless parameters determining when the nonideal nature of the gas has to be taken into account are estimated in more detail. It is found that the collision integral for bound particles can be integrated over the velocity space, which significantly simplifies the original system of equations and makes it possible to prove an H-theorem. The resulting system is nondimensionalized. A conservative numerical scheme is proposed for its solution.

The paper is devoted to the comparative study of Shakhov model kinetic equation and Direct Simulation Monte Carlo (DSMC) solutions as applied to high-speed flow of a monatomic gas over generic three-dimensional space vehicle under angle of attack. The corresponding calculations are carried out using Nesvetay and SMILE software packages, developed by the authors. Satisfactory agreement is shown for surface distribution of pressure, friction and heat transfer coefficients despite very different modeling approaches and computational meshes employed. It is thus shown that the use of the model kinetic equations with approximate collision integrals provides accurate results for high-speed external monatomic gas flows over complex three-dimensional geometries at acceptable computational cost. (C) 2019 Elsevier B.V. All rights reserved.

GaAs layers were grown by metalorganic epitaxy on Ge/Si(001) substrates, which were formed by chemical vapor deposition with decomposition of GeH 4 on a hot wire. High structural quality of thin Ge layers (0.2 - 0.3 μm) on a silicon substrate made it possible to grow high-quality GaAs layers. The resulting n + -GaAs/p-GaAs/p-Ge/p + -Si diode structures demonstrate low reverse currents.

AbstractA GaAs/AlAs/GaAs/AlAs/Ge heterostructure grown on a Si/Al_2O_3(1 $$\bar {1}$$ 02) substrate is formed and studied. The Ge buffer layer is produced by the “hot wire” technique, whereas the III–V layers are grown by metal–organic vapor-phase epitaxy. The optical quality of the III–V layers is determined by photoluminescence spectroscopy. Structural studies are performed by high-resolution transmission electron microscopy. The elemental composition is determined by energy-dispersive X-ray spectroscopy. In the study, the possibility of growing a single-crystal GaAs layer on a Si/Al_2O_3 substrate through AlAs/GaAs/AlAs/Ge buffer layers is shown.

A GaAs/AlAs/GaAs/AlAs/Ge heterostructure grown on a Si/Al2O3(1 $$\bar {1}$$ 02) substrate is formed and studied. The Ge buffer layer is produced by the “hot wire” technique, whereas the III–V layers are grown by metal–organic vapor-phase epitaxy. The optical quality of the III–V layers is determined by photoluminescence spectroscopy. Structural studies are performed by high-resolution transmission electron microscopy. The elemental composition is determined by energy-dispersive X-ray spectroscopy. In the study, the possibility of growing a single-crystal GaAs layer on a Si/Al2O3 substrate through AlAs/GaAs/AlAs/Ge buffer layers is shown.

GaAs/AlAs/GaAs/AlAs/Ge heterostructure grown on a Si/Al 2 O 3 (1 1̅ 02) substrate is formed and studied. The Ge buffer layer is produced by the “hot wire” technique, whereas the III–V layers are grown by metal–organic vapor-phase epitaxy. The optical quality of the III–V layers is determined by photoluminescence spectroscopy. Structural studies are performed by high-resolution transmission electron microscopy. The elemental composition is determined by energy-dispersive X-ray spectroscopy. In the study, the possibility of growing a single-crystal GaAs layer on a Si/Al 2 O 3 substrate through AlAs/GaAs/AlAs/Ge buffer layers is shown.

A model kinetic equation for a rarefied diatomic gas is used to obtain necessary and sufficient conditions for the existence of divergence-form conservation laws. For some types of force fields, new divergence forms of conservation laws are constructed. They are used to examine the general properties of the motion of a finite gas mass in a given field.

A GaAs/AlAs heterostructure and a GaAs film grown on Si/Ge substrates have been fabricated and studied. A Ge buffer on a silicon substrate was fabricated using the MBE process. A3B5 films were grown by MOCVD at low pressures. Photoluminescence spectroscopy was used to define the optical quality of A3B5 films. Structural properties were investigated using the electron beam induced current method. It was established that despite a rather high density of dislocations on the epitaxial layers, the detected photoluminescence radiation of layers indicates the acceptable crystalline quality of the top GaAs layer.

AbstractA laser structure comprising metamorphic InGaAsP layer and InGaAs quantum wells on a non-inclined Si(001) substrate with relaxed Ge buffer layer has been grown for the first time by metal-organic vapor phase epitaxy (MOVPE). The optically pumped lasers exhibit stimulated emission at a wavelength of 1.3 μm. At liquid-nitrogen temperature, the threshold power density of pumping at 0.8 μm amounted to 250 kW/cm^2.

AbstractStressed InGaAs/GaAs quantum-well laser structures are grown by gas-phase epitaxy from organometallic compounds on GaAs substrates and artificial Ge/Si substrates based on Si(001) with an epitaxial metamorphic Ge layer. To suppress the relaxation of elastic stresses during the growth of InGaAs quantum wells with a high fraction of In, strain-compensating GaAsP layers are applied. The structural and radiative properties of the samples grown on substrates of various types are compared. Stimulated radiation at wavelengths up to 1.24 μm at 300 K is obtained for structures grown on GaAs substrates and at wavelengths up to 1.1 μm at 77 K, for structures grown on Ge/Si substrates.

The paper presents the results of the application of MOCVD growth technique for formation of the GaAs/AlAs laser structures with InGaAs quantum wells on Si substrates with a relaxed Ge buffer. The fabricated laser diodes were of micro-striped type designed for the operation under the electrical pumping. Influence of the Si substrate offcut from the [001] direction, thickness of a Ge buffer and insertion of the AlAs/GaAs superlattice between Ge and GaAs on the structural and optical properties of fabricated samples was studied. The measured threshold current densities at room temperatures were 5.5 kA/cm2 and 20 kA/cm2 for lasers operating at 0.99 μm and 1.11 μm respectively. In order to obtain the stimulated emission at wavelengths longer than 1.1 μm, the InGaAs quantum well laser structures with high In content and GaAsP strain-compensating layers were grown both on Ge/Si and GaAs substrates. Structures grown on GaAs exhibited stimulated emission under optical pumping at the wavelengths of up to 1.24 μm at 300 K while those grown on Ge/Si substrates emitted at shorter wavelengths of up to 1.1 μm and only at 77 K. The main reasons for such performance worsening and also some approaches to overcome them are discussed. The obtained results have shown that monolithic integration of direct-gap A3B5 compounds on Si using MOCVD technology is rather promising approach for obtaining the Si-compatible on-chip effective light source.

In this paper we have investigated light-emitting diodes based on GaAs/InGaAs heterostructures grown on a Ge/Si(100) substrates. Ge layers were deposited by the "hot wire" method, and A3B5 layers were grown by the low pressure MOCVD. Structures were investigated by the methods of electroluminescence spectroscopy and electron beam induced currentimaging in a scanning electron microscope. Technological ways to improve crystalline quality of active region of light-emitting structures grown on Ge/Si(100) substrate were shown.

The result of investigation of InGaAs photodetectors grown on GaAs substrate with metamorphic InGaP buffer is shown in this paper. It has been shown experimentally that the use of the gradient InGaP metamorphic layer in an InGaAs photodiode structure improves the spectral characteristics and crystalline quality of the structure and leads to reduction of dark current by an order of magnitude compared to photodiodes fabricated with metamorphic InGaAs layers.