[en] The optical reflection in periodic structures based on a semiconductor AlGaAs matrix containing two-dimensional arrays of plasmonic AsSb nanoinclusions was studied. The number of periods was 12 or 24. The spatial period was near 110 nm in both cases. In the experimental optical reflection spectra at normal incidence we observed resonant Bragg diffraction with the main peaks at wavelengths of 757 or 775 nm, depending on the spatial period of the nanostructure. The magnitudes of the resonance peaks reached 19 and 31% for the systems of 12 and 24 AsSb–AlGaAs layers, while the volume fraction of the nanoinclusions was much less than 1%. In the case of light incident at inclined angles, the Bragg-diffraction pattern shifted according to Wulff-Bragg’s law. Numerical calculations of the optical reflection spectra were performed using the transfer-matrix method by taking into account the spatial geometry of the structures and the resonance characteristics of the plasmonic AsSb layers.

[en] Heterostructures with InAs/AlAs quantum dots are grown on GaAs/Si hybrid substrates. The experimentally observed low-temperature (5–80 K) photoluminescence spectra of InAs/AlAs/GaAs/Si heterostructures exhibit bands defined by excitonic recombination in quantum dots and a wetting layer, i.e., a thin quantum well lying at the base of the array of quantum dots. Temperature quenching of the photoluminescence of quantum dots occurs due to the direct trapping of charge carriers at defects localized in the AlAs matrix, in the vicinity of the quantum dots.

[en] The effect of substrate temperature, As_2 and P_2 molecular flux densities, and growth rate on the composition of III-P_xAs_1_−_x solid solution layers prepared by molecular beam epitaxy is experimentally investigated. Experimental data in a wide range of growth conditions are analyzed. The results obtained are presented in the form of a kinetic model for describing the process of formation of the composition in the Group V sublattice of the III-P_xAs_1_−_x solid solution upon molecular beam epitaxy. The model can be used for choosing the growth conditions of the III-P_xAs_1_−_x (001) solid-solution layers of a specified composition

[en] The processes of the diffusion blurring of a periodic system of GaAs quantum wells separated by AlGaAs barriers are studied by photoluminescence spectroscopy. The system is grown by molecular-beam epitaxy at a low temperature (200°C) and additionally doped with Sb and P isovalent impurities. Postgrowth annealing at the temperature 750°C for 30 min induces an increase in the energy corresponding to the photoluminescence peak of the e1–hh1 exciton state in quantum wells because of blurring of the epitaxial GaAs/AlGaAs interfaces due to enhanced Al–Ga interdiffusion in the cation sublattice. For the Al concentration profile defined by linear diffusion into quantum wells, the Schrödinger equation for electrons and holes is solved. It is found that the experimentally observed energy position of the photoluminescence peak corresponds to the Al–Ga interdiffusion length 3.4 nm and to the effective diffusion coefficient 6.3 × 10^–17 cm² s^–1 at the temperature 750°C. This value is found to be close to the corresponding value for GaAs quantum wells grown at low temperatures without additional doping with Sb and P impurities. From the results obtained in the study, it is possible to conclude that enhanced As–Sb and As–P interdiffusion in the anion sublattice only slightly influences the processes of Al–Ga interdiffusion in the cation sublattice.

[en] The optical reflection from periodic structures based on a semiconductor AlGaAs matrix containing 2D arrays of plasmonic AsSb nanoinclusions is studied. The number of nanoinclusion layers is 12 or 24, and the nominal spatial periods are 100 or 110 nm, respectively. In the experimental spectra of the optical reflection coefficient at normal incidence, we observe resonant Bragg diffraction with the main peaks at wavelengths of 757 or 775 nm (1.64 or 1.60 eV), depending on the spatial period of the nanostructure. The magnitudes of the resonance peaks reach 22 and 31% for the systems of 12 and 24 AsSb–AlGaAs layers, while the volume fraction of the nanoinclusions is much less than 1%. In the case of light incident at inclined angles, the Bragg-diffraction pattern shifts according to Wulff–Bragg’s law. Numerical simulation of the optical reflection spectra is performed using the transfer-matrix method by taking into account the spatial geometry of the structures and the resonance characteristics of the plasmonic AsSb layers.

[en] Molecular-beam epitaxy is used to produce GaP/Si hybrid substrates that allow the growth of highly efficient light-emitting heterostructures with GaAs/GaP quantum wells. Despite the relatively high concentration of nonradiative-recombination centers in GaP/Si layers, GaAs/GaP quantum-well heterostructures grown on GaP/Si hybrid substrates are highly competitive in terms of efficiency and temperature stability of luminescence to similar heterostructures grown on lattice-matched GaP substrates.

[en] The optical properties of metal-semiconductor metamaterials based on an AlGaAs matrix are studied. The specific feature of these materials is that there are As and AsSb nanoinclusion arrays which modify the dielectric properties of the material. These nanoinclusions are randomly arranged in the medium or form a Bragg structure with a reflectance peak at a wavelength close to 750 nm, corresponding to the transparency region of the matrix. The reflectance spectra are studied for s- and p-polarized light at different angles of incidence. It is shown that (i) As nanoinclusion arrays only slightly influence the optical properties of the medium in the wavelength range 700–900 nm, (ii) chaotic AsSb nanoinclusion arrays cause strong scattering of light, and (iii) the spatial periodicity in the arrangement of AsSb nanoinclusions is responsible for Bragg resonance in the optical reflection

[en] A single molecular-beam epitaxy process is used to produce GaAs-based heterostructures containing two-dimensional arrays of InAs semiconductor quantum dots and AsSb metal quantum dots. The twodimensional array of AsSb metal quantum dots is formed by low-temperature epitaxy which provides a large excess of arsenic in the epitaxial GaAs layer. During the growth of subsequent layers at a higher temperature, excess arsenic forms nanoinclusions, i.e., metal quantum dots in the GaAs matrix. The two-dimensional array of such metal quantum dots is created by the δ doping of a low-temperature GaAs layer with antimony which serves as a precursor for the heterogeneous nucleation of metal quantum dots and accumulates in them with the formation of AsSb metal alloy. The two-dimensional array of InAs semiconductor quantum dots is formed via the Stranski–Krastanov mechanism at the GaAs surface. Between the arrays of metal and semiconductor quantum dots, a 3-nm-thick AlAs barrier layer is grown. The total spacing between the arrays of metal and semiconductor quantum dots is 10 nm. Electron microscopy of the structure shows that the arrangement of metal quantum dots and semiconductor quantum dots in the two-dimensional arrays is spatially correlated. The spatial correlation is apparently caused by elastic strain and stress fields produced by both AsSb metal and InAs semiconductor quantum dots in the GaAs matrix

[en] The effect of a substrate misorientation degree from a singular face on the composition and morphology of layers of InAs_xSb_{1 –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 InAs_xSb_{1 –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.

[en] The photoluminescence of InAs semiconductor quantum dots overgrown by GaAs in the low-temperature mode (LT-GaAs) using various spacer layers or without them is studied. Spacer layers are thin GaAs or AlAs layers grown at temperatures normal for molecular-beam epitaxy (MBE). Direct overgrowth leads to photoluminescence disappearance. When using a thin GaAs spacer layer, the photoluminescence from InAs quantum dots is partially recovered; however, its intensity appears lower by two orders of magnitude than in the reference sample in which the quantum-dot array is overgrown at normal temperature. The use of wider-gap AlAs as a spacer-layer material leads to the enhancement of photoluminescence from InAs quantum dots, but it is still more than ten times lower than that of reference-sample emission. A model taking into account carrier generation by light, diffusion and tunneling from quantum dots to the LT-GaAs layer is constructed.