The subject of the study is the epitaxial layers of InAlAs and InP after Zn diffusion. The aim of the study is to develop a method of controlled Zn doping of InAlAs and InP epitaxial layers. Method. The doping is conducted through a narrow gap using a solid-state source based on Zn3P2 3 P 2 and rapid thermal annealing. The depth profiles of Zn concentration distribution in InAlAs and InP are determined using electrochemical capacitance-voltage (ECV) profiling. Additionally, the dopant diffusion depth is determined using scanning electron microscopy. Main results. At T = 500 degrees C, degrees C, the time dependence of the Zn doping depth in InP and InAlAs layers agrees closely with the diffusion (square root) dependence. Moreover, the calculations indicate that the effective diffusion coefficient in InP is 2.5 times higher than in InAlAs. The maximum achievable concentrations of electrically active dopant in the InP and InAlAs layers are ( 6 - 7 ) x 1017 17 and ( 3 - 4 ) x 1018 18 cm-3, - 3 , respectively. We observed that the presence of a thin (100 nm) InAlAs layer in the InP epitaxial layer can significantly retard the diffusion of Zn. Practical significance. The results on the diffusion of Zn in InAlAs and InP obtained in this study will serve as the basis for the development and manufacturing of prototypes of planar avalanche photodiode devices with reduced excess noise and a wide dynamic range of sensitivity. (c) 2024 Optica Publishing Group

Initial stage of precipitate formation during post-growth annealing of nonstoichiometric GaAs and GaAs0.97Sb0.03 grown by low-temperature (150°C) MBE on GaAs (001) substrate with intermediate growth interruption and simultaneous heating up to 250°C was studied by transmission electron microscopy. Short-term intermediate heating despite the low temperature was revealed to result in the precipitation of larger particles during subsequent post-growth annealing compared to the material not subjected to such heating. This effect is explained by the huge concentration of excess arsenic in LT-GaAs and LT-GaAs0.97Sb0.03 grown at 150°C, enhanced diffusion due to the high concentration of nonequilibrium gallium vacancies, and non-threshold nucleation.

by molecular-beam epitaxy we have grown epitaxial layers of GaAs1–xBix solid solutions with a bismuth content of 0 < x < 0.02. Structural and optical properties of the layers were investigated. We determine the influence of the bismuth flux and substrate temperature on the bismuth incorporation into the growing layers.

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.

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.

Epitaxial layers of Al x Ga 1-x As 1-y Sb y with an aluminum content x~60% and antimony content y~3% were successfully grown by molecular-beam epitaxy at low temperature. A developed system of AsSb nanoinclusions was formed in the semiconductor matrix by subsequent annealing. The extended transparency window of the obtained metamaterial allows us to document the absorption of light near the interband absorption edge of the Al x Ga 1-x As 1-y Sb y semiconductor matrix. Parameters of the observed extinction band allow us to attribute the optical absorption to the plasmon resonance in the system of AsSb nanoinclusions. Keywords: molecular beam epitaxy, x-ray diffraction analysis, transmission electron microscopy, optical properties, plasmon resonance.

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.

AlGaAsSb and AlGaAs films as thick as 1 μm with Al content as high as 60% were successfully grown by low-temperature (200 °C) MBE. To overcome the well-known problem of growth disruption due to a high aluminum content and a low growth temperature, we applied intermittent growth with the temperature elevation to smooth out the emerging roughness of the growth front. Post-growth annealing of the obtained material allowed us to form a developed system of As or AsSb nanoinclusions, which occupy 0.3–0.6% of the material volume. While the As nanoinclusions are optically inactive, the AsSb nanoinclusions provide a strong optical absorption near the band edge of the semiconductor matrix due to the Fröhlich plasmon resonance. Owing to the wider bandgap of the grown Al0.6Ga0.4As0.97Sb0.03 compound, we have expanded the spectral range available for studying the Fröhlich plasmon resonance. The grown metamaterial represents an optically active medium of which the formation process is completely compatible with the epitaxial growth technology of semiconductors.

The kinetics of the reflection signals of the nanostructures consisting of the same number of quantum wells with identical compositions InxGa1-xAs (x = 0, 32) with barriers of GaAs consisting of 2, 4, 6, and 8 monolayers grown on a semiconductor reflector under identical conditions has been studied by the pump-probe method. A trend of reduction of the recovery time for thinner barriers has been revealed. The prospects of further investigation and practical application of quantum wells coupled by tunneling of charge carriers have been discussed.

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.

The influence of the structure of quantum wells and the features of their manufacturing technology on the performance and maximum modulation depth of optical gates based on quantum wells A(3)B(5), designed for mode locking of near-IR lasers, is analyzed.

by molecular-beam epitaxy we have grown epitaxial layers of GaAs 1– x Bi x solid solutions with a bismuth content of 0 < x < 0 . 02. Structural and optical properties of the layers were investigated. We determine the influence of the bismuth flux and substrate temperature on the bismuth incorporation into the growing layers.

The design and fabrication of a single photon detector based on InP/InGaAs/InP single-photon avalanche diodes (SPADs) operating in Geiger mode at a telecommunication wave-length of 1550 nm are discussed. The SPAD design, the method for obtaining InP/InGaAs/ InP heterostructures by molecular beam epitaxy, fabrication of SPAD chips using planar technology, and specific features of selective zinc doping of p-regions in the InP layer of the developed electronic circuits for measuring main SPAD parameters are described. Preliminary results of measurements of the parameters of the fabricated SPADs are presented.

Fast semiconductor shutters based on coupled wells were designed in the search for reliable, compact and cheap key element of GHz repetition rate NIR lasers passive mode-locking. Stable 0.98 GHz repetition rate 200-fs Yb:KYW laser pulses were demonstrated for SESAM including semiconductor reflector and a layer of quantum wells. The damage threshold estimate for the SESAM is ∼ 8.87 mJ/cm2. Other type of shutter – DSAM – was developed with dielectric reflector and the layer of quantum wells transferred over reflector. The measured recovery time was about 2-3 ps for both types of saturable absorbers. The efficiency relative to the incident pump power was 57% for the SESAM and 19% for the DSAM. Average output power of 2.54 W for the all-semiconductor shutter (SESAM) and of 0.92 W for the dielectric mirror with a saturable absorber (DSAM) were obtained. Actual state of the art for the shutters design is considered.

The article presents a review of the design and manufacturing technology, methods and results of research on optical spectra and reflection kinetics of coupled quantum wells A(3)B(5), as well as the results of using optical gates developed on their basis for femtosecond laser mode locking Yb3+:KY(WO4)(2) with a high pulse repetition rate (about 1 GHz).

Проанализировано влияние строения квантовых ям и особенностей технологии их изготовления на быстродействие и максимальную глубину модуляции оптических затворов на основе квантовых ям A3B5, предназначенных для синхронизации мод лазеров ближнего ИК-диапазона.

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.

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.