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.

Experimental data on studying the phonon and optical properties of GaAs nanowires with orientation (111) located on a gold substrate with the help of Raman scattering spectroscopy (RSS) and photoluminescence (PL) are presented. Structural parameters of nanowires are determined by the atomic-force microscopy (AFM) and scanning electron microscopy (SEM) methods. In the micro-RSS and micro-PL spectra of a single GaAs nanowire, the modes of optical phonons of GaAs and their overtones up to the third order and an exciton luminescence band are observed. In the micro-PL spectra, anisotropy of the PL intensity is observed; the maximum/minimum signal is observed at the polarization-vector direction along/across the wire. Mapping of nano-PL of a single GaAs nanowire is performed with a spatial resolution of 20 nm, which is significantly smaller than the diffraction limit. When passing to the nanometer scale, a plasmon amplification of the signal of the near-field exciton nano-PL conditioned by the metallized AFM-needle is revealed.

A brief overview is presented of results obtained at the Rzhanov Institute of Semiconductor Physics in the development of photon detectors and emitters promising for use in quantum cryptography systems, along with miniature quantum frequency standards based on the effect of coherent population trapping.

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.

Локальный спектральный анализ полупроводниковых структур для устройств фотоники возможен с помощью наноспектроскопии, включая нано-КРС (комбинационное рассеяние света) и нано-ФЛ (фотолюминисценцию).Эти методы представляют собой комбинацию атомно-силовой микроскопии (АСМ) и КРС, либо ФЛ и основаны на усилении оптического сигнала наноструктуры полем локализованного поверхностного плазмона металлического зонда АСМ микроскопа могут быть применены для изучения фононного и электронного спектров двумерных (2D), одномерных (1D) и нульмерных (0D) отдельных полупроводниковых наноструктур с пространственным разрешением ниже дифракционного предела.Представлены результаты исследования нано-КРС на оптических фононах нанокристаллов (НК) CdSe и AlN наноколонн AlN и пленок графена и мультиграфена, помещенных на плазмонные подложки и нано-ФЛ нанокристаллов GaAs и двумерных островков дихалькогенидов металлов (MoS2 и WS2).В диапазоне частот оптических фононов выполнено нано-КРС коллоидных нанопластинок CdSe/CdS, сформированных по типу ядро/оболочка, монослоев MoS2, помещенные в зазоре между металлизированным (Au, Ag) острием АСМ микроскопа и плазмонной подложкой, определены размеры и форма наноструктур, структурные дефекты и возникающие в них механические напряжения.Обсуждается различие нано-КРС от НК CdSe на отдельном нанодиске золота, записанное при различных длинах волн возбуждения.Нано-КРС на частотах поверхностных оптических (SO) фононов наблюдалось от отдельных наноколонн AlN (1D), помещенных на поверхность Au, и НК AlN (0D), выращенных с помощью молекулярно-лучевой эпитаксии на Si, и.Нано-КРС изображение отдельного НК AlN размером около 250 нм с кристаллической структурой вюрцита демонстрирует его гексагональную форму.Обсуждаются различия в нано-КРС изображениях наноколонн AlN, записанных при различной поляризации света.Нано-ФЛ от монослойных островков MoS2 и WS2, выращенных кремниевой подложке, демонстрируют локальное изменение энергии и интенсивности экситонной ФЛ в зависимости от числа монослоев и наличия структурных дефектов.Обнаружено усиление непрямозонной нано-ФЛ в нанокристаллах GaAs, что позволило выполнить нано-ФЛ картирование отдельного нанокристалла.Исследование поддержано Российским Научным Фондом (грант №22-12-00302).

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.

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.

Методом молекулярно-лучевой эпитаксии при низкой температуре с использованием прерываний роста успешно выращены эпитаксиальные слои Al x Ga 1-x As 1-y Sb y с содержанием алюминия x~60% и содержанием сурьмы y~3%. Путем последующего отжига в полупроводниковой матрице сформирована развитая система нановключений AsSb. Увеличенное окно прозрачности полученного метаматериала позволило надежно документировать широкую полосу поглощения света вблизи края межзонного поглощения полупроводниковой матрицы Al x Ga 1-x As 1-y Sb y . Параметры наблюдаемой полосы экстинкции позволяют связать такое поглощение света с плазмонным резонансом в системе нановключений AsSb. Ключевые слова: молекулярно-лучевая эпитаксия, рентгенодифракционный анализ, просвечивающая электронная микроскопия, оптические свойства, плазмонный резонанс.

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.

Представлены экспериментальные данные по изучению фононных и оптических свойств нанопроволок GaAs ориентации (111), расположенных на золотой подложке с помощью методов спектроскопии комбинационного рассеяния света (КРС) и фотолюминесценции (ФЛ). Структурные параметры нанопроволок были определены методами атомно-силовой (АСМ) и сканирующей электронной микроскопии (СЭМ). В спектрах микроКРС и микроФЛ отдельной нанопроволоки GaAs наблюдаются моды оптических фононов GaAs и их обертонов, вплоть до третьего порядка, и полоса экситонной фотолюминесценции. В спектрах микроФЛ проявляется анизотропия интенсивности ФЛ в нанопроволоках, причём максимальный/минимальный сигнал наблюдается при направлении вектора поляризации вдоль/поперёк проволоки. Выполнено картирование наноФЛ отдельной нанопроволоки GaAs с пространственным разрешением 20 нм, что существенно меньше дифракционного предела. При переходе к нанометровым масштабам обнаружено плазмонное усиление сигнала ближнепольной экситонной наноФЛ, обусловленное металлизированной АСМ-иглой. The paper presents experimental data on phonon and optical properties of (111)-oriented GaAs nanowires on a gold substrate studied by means of Raman scattering and photoluminescence (PL). The structural parameters of the nanowires are determined by atomic force and scanning electron microscopy (AFM and SEM, respectively). In the micro-Raman and micro-PL spectra of a single GaAs nanowire, phonon modes of GaAs and their overtones up to the third order and an exciton photoluminescence band are observed. In the micro-PL spectra, anisotropy of the PL intensity in nanowires is revealed, and the maximum/minimum signal is observed when the polarization vector is directed along/across the wire. Nano-PL maps of a single GaAs nanowire with a spatial resolution of 20 nm are obtained, which is significantly smaller than the diffraction limit. Plasmon enhancement of the near-field exciton nano-PL in the vicinity of the metallized tip of the AFM microscope is detected.

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.