The possibility of InP nanowhiskers growth from the saturated phosphorus and indium vapors with V/III ratio of 8–10 in a quasi-closed volume on (111) oriented silicon substrates with a natural oxide layer 2–2.5 nm has been demonstrated. The growth of InP nanowhiskers from Au-In-P catalytic droplets formed during the initial period is reported. Optical studies confirmed the formation of InP nanostructures upon the Si surface. The nanostructures exhibit a high doping level presumably with tin atoms.

The possibility of controlling the composition of lateral nanowires by the method of growth under quasi-equilibrium conditions in a quasi-closed volume from indium, phosphorus, and arsenic vapors with Au catalyst in the “vapor-liquid-solid” mechanism has been demonstrated for the first time. It has been experimentally shown that the additional presence of arsenic in the indium-phosphorus source leads to the coalescence of catalytic gold droplets at the initial stage of the growth, which determines the further morphology and growth kinetics of nanostructures. An additional formation of indium phosphide nanostructures with a composition different from that of the main nanowires was found. The results of the studies expand the possibilities of the developed method for obtaining lateral nanowires on gallium arsenide substrates.

A new method for growth of Au-catalyzed lateral Ga(In)AsP nanostructures in a quasi-closed volume from a vapor source under semi-equilibrium conditions has been studied. Varied time-temperature conditions and nucleation modes were examined. It was found that lateral nanostructures elongated in the [1 (1) over bar0] direction are formed on a (100) GaAs substrate at about 500 degrees C. Raising the growth temperature is accompanied by a significant change of the morphology of the nanostructures. The modified surface has a random textured structure with predominant pyramidal faceting. Changes in the alloy composition of the nanostructures were studied.

Впервые продемонстрирована возможность управления составом латеральных нитевидных наноструктур при использовании метода роста в квазиравновесных условиях в квазизамкнутом объеме из паров индия, фосфора и мышьяка с использованием Au-катализатора по механизму "пар-жидкость-твердое тело". Эксп-риментально показано, что дополнительное присутствие мышьяка в источнике индий-фосфор приводит к коалесценции каталитических капель золота на начальном этапе роста, что определяет дальнейшую морфологию и кинетику роста наноструктур. Обнаружено дополнительное образование наноструктур фосфида индия с составом, отличным от состава основных нитевидных наноструктур. Результаты проведенных исследований значительно расширяют возможности разработанного нами метода получения латеральных нитевидных наноструктур на подложках арсенида галлия. Ключевые слова: планарные нитевидные нанокристаллы InGaAsP, механизм роста "пар--жидкость--твердое тело", спектроскопия комбинационного рассеяния, фотолюминесценция.

We have shown the possibility of Ga(In)AsP on GaAs (100) nanowire growth in a quasi-closed volume from the vapour phase witn the use of Sn catalyst. We have investigated the dynamics of nanowire formation depending on the growth time at constant V/III ratio given by the process temperature. It is shown that growth of free-standing nanowires is realized through the vapor-liquid-solid mechanism. Based on the Raman scattering data sequential growth of two phases have been shown. Phosphorous concentration in free-stamding nanowires was estimated to be high.

The possibility of lateral Ga (In) AsP nanostructures grown by a catalytic method in a quasi-closed volume from phosphorus and indium vapors on the GaAs (100) surface as an antireflection coating for photovoltaic devices is considered for the first time. It is shown that at fixed growth temperature, it is possible to control the surface morphology by changing the growth time. The surface morphology was investigated by scanning electron and atomic force microscopy. The dependence of surface reflection coefficient in the range of 400-800 nm on the surface structure is shown. The use of such coating in GaAs-based photocells demonstrated a significant increase in the external quantum yield of photoconverters.

The possibility of using lateral Ga(In)AsP nanostructures grown by the catalytic method in a quasi-closed volume from phosphorus and indium vapors on the GaAs (100) surface as an antireflection coating for photovoltaic devices is considered for the first time. It is shown that, at a fixed growth temperature, it is possible to control the surface morphology by changing the growth duration. The surface morphology is examined by scanning electron and atomic force microscopies. It is shown that the antireflection properties of the surface in the range 400–800 nm are related to its structure. The use of such a coating in GaAs-based photocells demonstrated a significant increase in the external quantum yield of photovoltaic converters.

An indium-phosphide InP sample subjected to the pore-generation procedure and then doped with S atoms is studied by the methods of X-ray diffraction analysis (XRD) and small-angle X-ray scattering (SAXS) (with Cu K α1 -radiation). The XRD data demonstrate that the sample consists of (coherent) aligned homogeneous components. A point detector is used to obtain, in the anomalous transmission mode by Borrmann, a set of SAXS curves at sample positions varied by azimuthal rotations. The SAXS data are used to simulate a 2D SAXS pattern for the sample under study, which makes it possible to determine the long-distance translation symmetry and, consequently, the presence of a superstructure. The interplanar distances in the superstructure in the directions (110) and (1 0) of the InP lattice are found to be ~260 and 450 nm, respectively. The symmetry group of the superstructure is determined as C 2 v in the (001) plane of the sample lattice.

The formation of nanostructures on the surface of GaAs under quasi-equilibrium conditions in a quasi-closed volume from saturated phosphor and indium vapors in the presence of a Au catalyst with growth according to the “vapor–liquid–crystal” mechanism is considered for the first time. The influence of the growth temperature and size of Au drops on the morphology and composition of the fabricated nanostructures is studied. Experimental data on the formation of Ga(In)AsP nanocrystals on GaAs substrates with various orientations are presented. It is established that the temperature growth range of the nanostructures when using this method is 540–640°C with a drop size from 30 to 120 nm. It is shown that the size of the catalyst drops substantially affects the morphology and growth rate of the fabricated nanostructures while their composition weakly depends on both the drop size and the substrate orientation.

AbstractAn indium-phosphide InP sample subjected to the pore-generation procedure and then doped with S atoms is studied by the methods of X-ray diffraction analysis (XRD) and small-angle X-ray scattering (SAXS) (with Cu K _α1-radiation). The XRD data demonstrate that the sample consists of (coherent) aligned homogeneous components. A point detector is used to obtain, in the anomalous transmission mode by Borrmann, a set of SAXS curves at sample positions varied by azimuthal rotations. The SAXS data are used to simulate a 2D SAXS pattern for the sample under study, which makes it possible to determine the long-distance translation symmetry and, consequently, the presence of a superstructure. The interplanar distances in the superstructure in the directions (110) and (1 0) of the InP lattice are found to be ~260 and 450 nm, respectively. The symmetry group of the superstructure is determined as C _2 v in the (001) plane of the sample lattice.

AbstractThe formation of nanostructures on the surface of GaAs under quasi-equilibrium conditions in a quasi-closed volume from saturated phosphor and indium vapors in the presence of a Au catalyst with growth according to the “vapor–liquid–crystal” mechanism is considered for the first time. The influence of the growth temperature and size of Au drops on the morphology and composition of the fabricated nanostructures is studied. Experimental data on the formation of Ga(In)AsP nanocrystals on GaAs substrates with various orientations are presented. It is established that the temperature growth range of the nanostructures when using this method is 540–640°C with a drop size from 30 to 120 nm. It is shown that the size of the catalyst drops substantially affects the morphology and growth rate of the fabricated nanostructures while their composition weakly depends on both the drop size and the substrate orientation.

The results of studies of the surface of GaAs in the presence of indium and phosphorus surfactants are reported. It is shown that, as a result of their diffusion (annealing) at a temperature of 650–670°C, clusters enriched with indium are formed in the GaAs surface region. The clusters can be seen as bright spots in an image obtained by a scanning electron microscope with the use of an in-lens detector. At the same time, studies of the morphology of this surface with an atomic-force microscope show a decrease in the root-meansquare roughness of the surface after annealing (diffusion), which is indicative of the incorporation of In atoms into the GaAs crystal lattice. The clusters are responsible for changes in the Raman spectra. Specifically, an increase in the signal intensity due to surface-enhanced Raman scattering and a shift of the vibration frequency in the surface region are observed. It is found that cluster formation is defined by the crystallographic orientation of the surface and by the technological conditions of surface preparation.

Приведены сравнительные характеристики фотовольтаических преобразователей лазерного излучения на основе арсенида галлия с p-эмиттером, сформированным диффузией из газовой фазы в присутствии сурфактантов (изовалентных примесей) и без них. Показано, что использование индия и фосфора в процессе формирования p-n-перехода существенно влияет на характеристики полученных приборов. DOI: 10.21883/FTP.2017.05.44432.8477

The comparative characteristics of photovoltaic converters (of laser radiation) based on gallium arsenide with a p-type emitter formed by gas-phase diffusion in the presence of surfactants (isovalent impurities) and without them are reported. It is shown that the use of indium and phosphorus in the process of the formation of a p–n junction significantly affects the characteristics of the obtained devices.

Представлены результаты исследований поверхности GaAs в присутствии сурфактантов индия и фосфора. Показано, что в результате их диффузии (отжига) при температуре 650-670oC в приповерхностной области GaAs образуются кластеры, обогащенные индием. Кластеры проявляются в виде светлых пятен в изображении, полученном с помощью внутрилинзового детектора на сканирующем электронном микроскопе. В то же время исследования морфологии этой поверхности с помощью атомно-силового микроскопа обнаружили уменьшение значения среднеквадратичной шероховатости поверхности после процесса отжига (диффузии), что указывает на внедрение атомов индия в кристаллическую решетку GaAs. Кластеры ответственны за изменения в спектрах рамановского рассеяния: наблюдаются увеличение интенсивности сигнала, вызванное эффектом поверхностно-усиленного (гигантского) рамановского рассеяния, и сдвиг частоты колебаний в приповерхностной области. Обнаружено, что эффект формирования кластеров обусловлен как кристаллографической ориентацией поверхности, так и технологическими условиями ее подготовки. DOI: 10.21883/FTP.2017.05.44461.8453

The diffusion of Zn into GaAs in the presence of indium and phosphorus was studied. Zn diffusion was performed from the gas phase in a hydrogen flow under isothermal conditions (670 degrees C). A GaAs substrate was annealed in In and P vapors in a separate chamber. The annealing conditions simulated the memory effect of a MOVPE reactor and/or the cross-doping during the growth of multilayer structures based on III-V alloys. The aim of the current research was to study the effects of In and P on the Zn diffusion processes in GaAs. The results obtained by secondary-ion mass spectrometry show that, upon a pretreatment with In and P, both the incorporation efficiency and the diffusion rate of Zn increase. Measurements by Raman spectroscopy confirm the increase in the free-hole concentration in the sub-surface layers in pre-annealed samples. The influence of In and P on the diffusion process was observed at concentrations higher than 1017 cm(-3).Optical characterization reveals changes in the defect distribution in the GaAs samples. The changes of the recombination processes, caused by In and P, depend on the indium vs. phosphorus ratio. The effective Zn diffusion rate is controlled by this ratio. (C) 2015 Published by Elsevier B.V.

A study of the effect of isoelectronic surfactants (In and P) on the photoluminescence and photovoltaic characteristics of GaAs–Ge heterostructures is presented. The surfactants were introduced into the structure by simultaneous post-growth diffusion. A GaAs photoluminescence spectra analysis was performed via a layer-by-layer etching procedure. It is shown that the effect of the surfactants is observed over a wide concentration range from 3×1017 to 1×1020cm−3. The effects of the In and P passivation of nonradiative recombination centers are observed. A p–n junction was formed via phosphorus diffusion. PV conversion efficiency of 3.2% for the 900–1840nm wavelength region has been registered under 40–400x concentrated sunlight (AM1.5D low-AOD).

A concentrator photovoltaic module with sunlight spectral splitting by Fresnel lens and dichroic filters is developed. The photoelectric conversion efficiency of such a module is estimated at a level of 49.4% when three single-junction cells are used and may reach 48.5–50.6% when a tandem two-junction cell is combined with narrow-band cells. Single-junction AlGaAs, GaAs, GaSb, and InGa(P)As solar sells are fabricated by zinc diffusion from the vapor phase into an n-type epitaxial layer. GaInP/GaAs cascade solar cells are prepared by MOS hydride epitaxy. The overall efficiency of the three single-junction solar cells developed for the spectral-splitting module is 38.1% (AM1.5D) at concentration ratio K c = 200x. The combination of the solar cells with the cascade structure demonstrates an efficiency of 37.9% at concentrations of 400–800 suns. The parameters of the spectral-splitting photovoltaic module are measured. The photovoltaic efficiency of this module reaches 24.7% in the case of three single-junction cells and 27.9% when the two-junction and single-junction cells are combined.