In this work, the formation, structural properties, and energy spectrum of novel self-assembled GaSb/AlP quantum dots (SAQDs) were studied by experimental methods. The growth conditions for the SAQDs’ formation by molecular beam epitaxy on both matched GaP and artificial GaP/Si substrates were determined. An almost complete plastic relaxation of the elastic strain in SAQDs was reached. The strain relaxation in the SAQDs on the GaP/Si substrates does not lead to a reduction in the SAQDs luminescence efficiency, while the introduction of dislocations into SAQDs on the GaP substrates induced a strong quenching of SAQDs luminescence. Probably, this difference is caused by the introduction of Lomer 90°-dislocations without uncompensated atomic bonds in GaP/Si-based SAQDs, while threading 60°-dislocations are introduced into GaP-based SAQDs. It was shown that GaP/Si-based SAQDs have an energy spectrum of type II with an indirect bandgap and the ground electronic state belonging to the X-valley of the AlP conduction band. The hole localization energy in these SAQDs was estimated equal to 1.65–1.70 eV. This fact allows us to predict the charge storage time in the SAQDs to be as long as >>10 years, and it makes GaSb/AlP SAQDs promising objects for creating universal memory cells.

The experimental dependences of the GaPx As1−x solid solution phosphorus proportion on growth conditions by molecular beam epitaxy from As2 and P2 molecules on GaAs(001) substrate were described using the phenomenological model. The model was built on the well-established ideas about the III−V compounds MBE growth. The ratio of the arsenic and phosphorus atoms incorporation coefficients was considered as a function of the substrate temperature and molecular flux densitys. Empirical expressions were found that describe the behavior of the arsenic and phosphorus incorporation coefficients ratio depending on the indicated growth parameters. This makes it possible to estimate the V group molecule flux values to obtain the required x in a GaPx As1−x solid solution at the given substrate temperature and the gallium atoms flow density.

Structures with arrays of planar and tilted quasi-one-dimensional GaAs nanocrystals have been grown on GaAs(001) substrates. An epitaxial silicon layer oxidized in air was used as a passivation coating. The amount of silicon deposited varied from structure to structure and was equivalent to 1, 2, 4, and 6 atomic layers. It has been found that in the case of a passivation layer based on silicon with a thickness of 1 atomic layer, an array of planar nanocrystals is formed, and in other cases, inclined quasi-one-dimensional nanocrystals. Nanocrystals are surrounded by crystallites, the shape, size, orientation, and distribution density of which change with the amount of silicon. The lowest density of crystallites was achieved with a silicon layer 6 atomic layers thick. Keywords: molecular-beam epitaxial, GaAs, Si, quasi-one-dimensional nanocrystals, vapour-liquid-crystal.

Structures with arrays of planar and tilted quasi-one-dimensional GaAs nanocrystals have been grown on GaAs(001) substrates. An epitaxial silicon layer oxidized in air was used as a passivation coating. The amount of silicon deposited varied from structure to structure and was equivalent to 1, 2, 4, and 6 atomic layers. It has been found that in the case of a passivation layer based on silicon with a thickness of 1 atomic layer, an array of planar nanocrystals is formed, and in other cases, inclined quasi-one-dimensional nanocrystals. Nanocrystals are surrounded by crystallites, the shape, size, orientation, and distribution density of which change with the amount of silicon. The lowest density of crystallites was achieved with a silicon layer 6 atomic layers thick.

The use of low-temperature (LT) GaAs layers as dislocation filters in GaAs/Si heterostructures (HSs) was investigated in this study. The effects of intermediate LT-GaAs layers and of the post-growth and cyclic in situ annealing on the structural properties of GaAs/LT-GaAs/GaAs/Si(001) HSs were studied. It was found that the introduction of LT-GaAs layers, in combination with post-growth cyclic annealing, reduced the threading dislocation density down to 5 × 106 cm−2, the root-mean-square roughness of the GaAs surface down to 1.1 nm, and the concentration of non-radiative recombination centers in the near-surface GaAs/Si regions down to the homoepitaxial GaAs level. Possible reasons for the improvement in the quality of near-surface GaAs layers are discussed. On the one hand, the presence of elastic deformations in the GaAs/LT-GaAs system led to dislocation line bending. On the other hand, gallium vacancies, formed in the LT-GaAs layers, diffused into the overlying GaAs layers and led to an increase in the dislocation glide rate. It was demonstrated that the GaAs/Si HSs obtained with these techniques are suitable for growing high-quality light-emitting HSs with self-assembled quantum dots.

GaSb films were grown by molecular beam epitaxy on vicinal Si(001) substrates with miscut angles of 6o to the (111) plane. Films were formed on AlSb(001)/Al/As/Si, AlSb(001)/Al/As/Si, GaSb(001)/Ga/P/Si and GaSb(001)/P/Ga/Si transition layers. The influence of orientation, composition, and formation conditions of transition layers on the crystal perfection and optical properties of GaSb films was studied. The GaSb film grown on the GaSb(001)/Ga/P/Si(001) transition layer has the best structural and optical properties. Keywords: molecular beam epitaxy, GaSb on Si(001), crystallographic orientation of the film, transition layers, antiphase domains, crystal perfection.

GaSb films were grown by molecular beam epitaxy on vicinal Si(001) substrates with miscut angles of 6° to the (111) plane. Films were formed on AlSb(001)/Al/As/Si, AlSb(00-1)/Al/As/Si, GaSb(00-1)/Ga/P/Si and GaSb(001)/P/Ga/Si transition layers. The influence of orientation, composition, and formation conditions of transition layers on the crystal perfection and optical properties of GaSb films was studied. The GaSb film grown on the GaSb(00-1)/Ga/P/Si(001) transition layer has the best structural and optical properties.

The effect of the growth rate (flow density of In atoms) on the composition of InAsxSb1-x(100) solid solutions at molecular beam epitaxy is experimentally studied using the flows of As-2 and Sb-4 molecules. It is established that the increase in the growth rate at constant fraction of As-2 and Sb-4 molecules in the flow of molecules of group V and unchanged fraction of the flow of indium atoms to the total flow of molecules of the group V elements leads to decrease in the arsenic fraction in the solid solution. It is shown that the growth rate is an independent parameter of the process of molecular beam epitaxy determining the composition of InAsxSb1-x solid solutions. The mechanism of generation of the solid solution compound explaining the role of growth rate is proposed.

Possibility of formation of pseudomorphous quantum well consisting of InGaAsP quaternary alloy during InAs deposition on GaP/Si epitaxial film surface with developed relief is demonstrated. Investigations of quantum well were performed by transmission electron microscopy and spectroscopy of cw photoluminescence. The appearance of quantum well segments of 2 types with different width and composition InGaAsP is demonstrated. Width increasing is accompanied by decreasing of In and As atoms fraction. Lateral sizes of quantum well segments are not lower than 20 nm. Different photoluminescence bands are corresponds to quantum well segments. Observed phenomenon are explained in the framework of suggestion about strain induced surface reorganization during InAs heteroepitaxy on terraced GaP surface.

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.

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$$\bar {1}$$)/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.

GaAs nanowires (NWs) were generated on the surface of GaAs(111) B and GaAs(100) substrates from molecular fluxes by the self-catalytic growth method. A mask for NW growth was fabricated by oxidizing the epitaxial silicon layer that was grown on a substrate surface by the molecular beam epitaxy (MBE) method. Silicon was oxidized in purified air without moving the structures out of the vacuum system of the MBE apparatus. The process of Si/GaAs heterostructure oxidation was investigated using single-wave and spectral ellipsometry. The oxidized silicon surface morphology was studied by the atomic force microscopy methods. The scanning electronic microscopy method was used to examine the samples with NWs. The NW density was about 2.6 × 10 7 and 3 × 10 7 cm –2 for (111) B and (100), respectively.

GaAs nanowire (NW) self-catalyzed growth on GaAs (111) B and GaAs (100) substrates was carried out by molecular beam epitaxy. A mask for the self-catalyzed NW growth was created by oxidizing an epitaxial silicon layer grown on the GaAs surface by molecular beam epitaxy (MBE). Silicon oxidation was realized in an atmosphere of purified air under normal conditions without moving the structures out from the vacuum system volume of the molecular beam epitaxy chamber. The oxidation process of a silicon layer was studied using single-wave and spectral ellipsometry and the surface morphology of oxidized silicon was studied by atomic force microscopy. Substrates with NWs were studied by scanning electron microscopy. The NW density was demonstrated to be 2.6•107 cm-2 and 3•107 cm-2 for (111)B and (100), respectively.

GaSb films were grown by molecular beam epitaxy using AlSb/As/Si transition layers on vicinal Si (001) substrates deflected 6 to the (111) plane. The influence of the GaSb films crystallographic orientation on their structural properties and surface morphology is investigated. It was found that GaSb(001 ̅)/Si films are characterized by better structural perfection, lower concentration of point defects and more planar and isotropic surface topography, compared with GaSb(001) films. Possible reason for the observed differences between GaSb films with different orientations is increased density of antiphase domains in GaSb(001) films. The morphological features of the grown films are caused by the terraces edges basically and by the anisotropy of the incorporation of Ga adatoms into the terraces edges, to a lesser extent.

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.

The influence of substrate misorientation degree on the composition and morphology of layers during molecular-beam epitaxy of InAsxSb1−x solid solutions on the GaAs surface was studied. The GaAs wafers with orientation (001), which were miscuted in the [110] direction by 0, 1, 2 and 5◦, were used as substrates. The growth of heterostructures was performed for temperatures of 310◦C and 380◦C (lower and upper boundaries for the temperature range of structurally perfect InAsx Sb1−x films formation, respectively). The influence of the arsenic molecular form (As2 or As4) on the composition of layers was studied. Studies of composition and structural properties were carried out using high-resolution X-ray diffractometry (HRXRD) and atomic force microscopy (AFM). It was established that in the series of misorientation from 0 to 5◦ the arsenic fraction x increases consecutively with the use of both flux of As2 and flux of As4 molecules. When the flux of As2 molecules is used, the fraction x increases insignificantly (in 1.05 times) with a rise of misorientation degree, but when using As4 molecules, x increases in 1.75 times. The increase of the growth temperature leads to the rise of the arsenic fraction in the solid solution. The morphology of the surface improves during increasing of misorientation degree at a low growth temperature and degrades at high temperatures.

The evolution of RHEED reflexes intensity during reconstructed transitions characterizes (often implicitly) reconstructed surface state peculiarities. The approaches of a correct RHEED data interpretation, aimed at obtaining information about reconstructed transitions kinetics, are considered in the present work. In particular, the nature of RHEED reflexes formation, depending on such parameters as the average size of reconstructed domains and number of such domains per area unit, is analyzed within the kinematic approximation of the diffraction theory. This geometrical description is a convenient and effective (productive) way of analyzing reconstructed transitions mechanisms and parameters. The transformation of the functional dependence between the measured values (RHEED reflexes intensity picture) and the degree of surface coverage by reconstruction domains, at a change of these domains average size and distribution density, is shown. This work provides the community with a useful framework for such type of theoretical studies.

The kinetic model of composition forming process in cation sublattice of the InAs x Sb 1-x solid solution during molecular beam epitaxy (MBE) is proposed. This model describes well the obtained experimental data dependence of InAs x Sb 1-x solid solution composition on such parameters, as GaAs(001) substrate misorientation degree, growth temperature and molecular form of arsenic in the flux (As 2 or As 4 ). The obtained results can be used to select optimal conditions of InAs x Sb 1-x solid solution growth with preassigned composition by MBE method.