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.

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.

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.

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.

The electronic structure of single-walled carbon nanotubes was experimentally investigated using x-ray photoelectron spectroscopy, reflection electron energy-loss spectroscopy, and Auger electron spectroscopy. A shake-up satellite structure observed near the C 1s core-level lines in the x-ray photoelectron spectra at high binding energies in the range 284–330 eV due to excitation of π and π + σ plasmons was studied. The effect of irradiation by 1-keV argon ions on the shape of the spectra was analyzed. The shape of the C 1s satellite spectra was found to be sensitive to Ar+ irradiation in the electron energy loss range 10–40 eV corresponding to excitation of π + σ plasmons. Auger spectroscopy revealed the presence of argon on the surface of ion-irradiated samples. The argon content increased to ∼4 at. % with increasing irradiation dose. An analysis of the results obtained and their comparison with the data available in the literature led to a qualitative conclusion that the bond angles of the carbon atoms making up the walls of single-walled carbon nanotubes are distorted at sites exposed to Ar+ irradiation.

The formation of defects in carbon nanotubes under irradiation with argon ions is investigated. The π plasmons generated in single-walled and multiwalled carbon nanotubes are examined using electron energy-loss spectroscopy. In the course of experiments, the supramolecular structure of nanotubes is stepwise modified by an argon ion beam (the maximum irradiation dose is 360 μC/cm2). The content of argon ions implanted into a nanotube structure is controlled using Auger electron spectroscopy. The effect of ion irradiation on the π-plasmon energy Eπ and on the half-width at half-maximum δE of the π-plasmon spectrum is determined experimentally. An expression relating the above quantities and the concentration of implanted argon is derived. It is shown that the formation of defects under ion irradiation is a discontinuous process occurring in a stepwise manner. A qualitative phenomenological interpretation is proposed for the experimentally revealed decrease in the π-plasmon energy Eπ and for its attendant broadening of the π-plasmon spectrum. The assumption is made that the microscopic mechanism of the observed phenomena is associated with the narrowing of the energy π subbands in the electric field of charged defects generated by ions.

The results of experimental study of SWNTs and MWNTs are presented. They were obtained by XPS, REELS and AES. The samples of SWNTs and MWNTs were periodically irradiated by argon ions (Ar+). The Ar+ energy was 1 keV. The maximum dose (Q) of Ar+ irradiation was 360 μC/cm2. The process of Ar absorption by SWNTs and MWNTs reveals nonlinear character. The dependence of the π+σ‐plasmon energy and the full width at the half of the maximum on Q were determined. Possible causes of the observed effects are discussed. The microscopic model is proposed.

Nominally pure and Yb-activated Czochralski-grown (Na0.5Gd0.5)WO4 crystals (scheelite type) were studied by x-ray diffraction (phase analysis, unit-cell parameters, and structure refinement by the Rietveld method and single-crystal techniques). A pseudotetragonal (orthorhombic) superstructure was revealed, which was shown to have doubled unit-cell parameters compared to the scheelite cell. Some of the crystals were found to contain tungsten and oxygen vacancies, which give rise to additional optical absorption. The effects of the growth and heat-treatment conditions and Yb activation on the structure, defect system, and additional absorption spectrum of (Na0.5Gd0.5)WO4 are analyzed.

Thin ultradisperse diamond (UDD) layers deposited from a water suspension are studied by optical and x-ray photoelectron spectroscopy (XPS). The effective band gap determined by the 10 4 -cm −1 criterion for ozone-cleaned UDD is 3.5 eV. The broad structureless photoluminescence band (380–520 nm) is associated with radiative recombination through a system of continuously distributed energy levels in the band gap of diamond nanoclusters. The optical absorption of the material at 250–1000 nm originates from absorption on the disordered nanocluster surface containing threefold-coordinated carbon. The surface of UDD clusters subjected to acid cleaning contains nitrogen-oxygen complexes adsorbed in the form of NO 3 − nitrate ions. Annealing in a hydrogen atmosphere results in desorption of the nitrate ions from the cluster surface. The evolution of the oxygen (O1 s ) and nitrogen (N1 s ) lines in the XPS spectra under annealing of a UDD layer is studied comprehensively.