The results of investigations on crystallization of silicon nanoclusters in a-SiOx matrix have shown that, even at the very fast annealing using pulse photonic annealing (PPA) formation of rather large silicon crystallites (> 100 nm) occurs, as well as the arrays of Si nanocrystals with average sizes of -10 nm and small sizes of -1-2 nm happens. It is shown that with an increase in the concentration of nanoclusters in the initial film from 15 to 53%, the contribution of large crystals (larger than 100 nm) increases from 15% (at 15% ncl-Si) to 65% (at 53% ncl-Si), which says on an increase in the probability of coalescence of crystallites into substantially larger ones with an increase of ncl-Si content in the initial film, despite the high annealing speed.

Amorphous SiOx films with silicon nanoclusters are a new interesting material from the standpoint of the physics, technology, and possible practical applications, since such films can exhibit photoluminescence due to size quantization. Moreover, the optical properties of these structures can be controlled by varying the size and the content of silicon nanoclusters in the SiOx film, as well as by transforming nanoclusters into nanocrystals by means of high-temperature annealing. However, during the annealing of nonstoichiometric silicon oxide, significant changes can occur in the phase composition and the structure of the films. The results of investigations on the crystallization of silicon nanoclusters in a SiOx matrix have shown that, even a very fast method of annealing using PPA leads to the formation of large silicon crystallites. This also causes the crystallization of at least a part of the oxide phase in the form of silicon hydroxide H6O7Si2. Moreover, in films with an initial content of pure silicon nanoclusters ≤ 50%, during annealing a part of the silicon is spent on the formation of oxide, and part of it is spent on the formation of silicon crystals. While in a film with an initial concentration of silicon nanoclusters ≥ 53%, on the contrary, upon annealing, there occurs a partial transition of silicon from the oxide phase to the growth of Si crystals

The β $$ \rightleftarrows $$ α phase transformations in foil of the Pd–52 at % Cu solid solution prepared by rolling have been studied using X-ray diffractometry and resistivity measurements during thermal heating–cooling cycles or lamp processing (LP) using light from high-power pulsed xenon lamps, followed by cooling. The results demonstrate that complete ordering of the two-phase (α + β) as-prepared (as-rolled) foil follows the sequence (α + β) → β → α → β in the first heating–cooling cycle and β → α → β in the second and subsequent cycles. When a radiative energy critical for a given thickness of foil with an ordered structure is delivered to the foil surface, an irreversible β → α phase transformation occurs, whose rate can be three orders of magnitude higher than the rate characteristic of the disordering process during Joule heating. After LP, the reversibility of the β $$ \rightleftarrows $$ α phase transformations, inherent in the initial, ordered structure, is observed in a second thermal cycle: heating to 700°C and cooling. The sequence of phase transitions is α → β → α → β in the first cycle and β → α → β in the second and subsequent cycles. The localization of light in the skin layer and finite thermal conductivity offer the possibility of producing a structure with a phase composition gradient at subcritical irradiation times. The fact that the LP-stabilized α-phase persists up to 300°C makes it possible to compare the mechanical properties of foil samples having identical elemental compositions but different (ordered and disordered) structures.

The effectiveness of flash lamp processing and ion beam sputtering in surface cleaning of membrane foil from a Pd–Cu solid solution produced by rolling has been assessed using cyclic voltammetry and atomic force microscopy. It has been shown that it is reasonable to use cyclic voltammetry for assessing the degree of foil surface cleaning and that combined surface processing of membrane foil is effective in foil surface cleaning. Ion beam processing reproducing the surface elemental composition corresponding to the original composition of the solid solution and increasing surface roughness is a factor of 1.3 more effective than combined surface processing.

Using X-ray phase analysis, scanning electron microscopy atomic force and magnetic force microscopy, and IR spectroscopy the properties of polycrystalline TiO2 films modified by cobalt during magnetron sputtering and subsequent pulsed photon processing in air have been investigated. It has been found that in the course of the modification, a nanocrystalline (with a grain size of ~ 50 nm) film consisting of cobalt and titanium oxides is formed. Their surface exhibits magnetic properties. In the IR reflection spectra obtained at different incident angle of beam, two of the transverse optical (TO) phonons and their corresponding longitudinal (LO) phonons above 500–600 cm–1 were observed, which identify the formation of Co3O4 in the spinel structure. The study of optical absorption indicates the predominant existence in the films of phases with direct optical transitions. The optical band gap value was 1.43 and 1. 83 eV for Co3O4 and 2.65 eV for the cubic phase of CoO.

transformations in a thin ~4 m foil of PdCu solid solution were investigated by x-ray diffractometry and measurement of electrical resistance in heating-cooling cycles during thermal or rapid photon treatment by radiation of high-power pulsed xenon lamps. It has been found that a single rapid photon treatment for 0,3 s (the energy dose of the radiation entering the sample is 10 j cm‑2) leads to a complete disordering of the solid solution at a rate 400 times greater than in the heat treatment mode used (heating at a rate of 15 K min‑1).

Методами рентгеновской дифрактометрии, измерения электросопротивления в циклах нагревание-охлаждение термической или быстрой фотонной обработкой излучением мощных импульсных ксеноновых ламп исследованы β ↔ α превращения в тонкой ~4 мкм фольге твёрдого раствора PdCu. Установлено, что однократная быстрая фотонная обработка в течение 0,3 с (доза энергии поступающего на образец излучения 10 Дж · см ‑ 2 ) приводит к полному разупорядочению твёрдого раствора со скоростью в 400 раз большей, чем в используемом режиме термической обработки (нагревание со скоростью 15 К · мин ‑ 1 ).

Properties of polycrystalline TiO 2 films modified by magnetron sputtering of cobalt followed by pulsed photon-irradiation processing in air are investigated by methods of X-ray phase analysis, raster electron microscopy, atomic force microscopy, magnetic force microscopy, and IR spectroscopy. Formation of a nanocrystalline (with a grain size of ~50 nm) film consisting of cobalt and titanium oxides the surface of which exhibits magnetic properties is established in the process of modification. The IR reflectance spectra obtained at different angles of incidence in the region between 500 and 600 cm –1 reveal the presence of two bands belonging to transverse modes (TO) and two corresponding bands belonging to the longitudinal modes (LO). These bands are indicative of formation of Co 3 О 4 with spinel structure. Investigation of optical absorption suggests a predominant existence of phases characterized by direct interband transitions with energies of 1.43 and 1.83 eV for Co 3 O 4 , along with a transition with energy of 2.65 eV for cubic phase of CoO, in the films.

The peculiarities of the phase composition and electronic structure of aluminum–silicon composite films near the Al 0.75 Si 0.25 composition obtained by the magnetron and ion-beam sputtering methods on a Si(100) silicon substrate are studied using the X-ray diffraction techniques and ultrasoft X-ray emission spectroscopy. In addition to silicon nanocrystals of about 25 nm in size, an ordered solid solution corresponding to the previously unknown Al 3 Si phase is formed in magnetron sputtering on a polycrystalline Al matrix. Films obtained by ion-beam sputtering of the composite target are found to be monophasic and contained only one phase of an ordered solid solution of aluminum silicide Al 3 Si of the Pm3m cubic system with the primitive cell parameter a = 4.085 Å. However, subsequent pulsed photon annealing of the composite with different radiation doses from 145 to 216 J/cm 2 gives rise to the partial decomposition of the Al 3 Si phase with the formation of free metallic aluminum and silicon nanocrystals with sizes in the range from 50 to 100 nm, depending on the pulsed photon radiation dose.

Исследованы фазовый состав и электронное строение композитных пленок Al-Si вблизи состава Al0.75Si0.25 на подложке Si(100), полученных магнетронным и ионно-лучевым напылением. При магнетронном напылении в поликристаллической Al матрице образуются нанокристаллы кремния размерами ~25 нм и упорядоченный твердый раствор Al3Si кубической сингонии Рm3m с параметром примитивной ячейки a = 4.085 Å. Пленки, полученные ионно-лучевым напылением, однофазны и содержат только упорядоченный твердый раствор Al3Si. При этом образование фазы Al3Si сопровождается изменением характера распределения плотности Al 3s-состояний. Вместо параболического характера роста плотности состояний в нижней и средней части валентной зоны (как в чистом металле) наблюдается почти линейный. Аналогичный эффект отмечается для Si 3s-состояний. Кроме того, взаимодействие атомов Al и Si приводит к уменьшению плотности Al 3s-состояний вблизи уровня Ферми в результате перехода части электронов на более электроотрицательные атомы кремния. Селективное вытравливание алюминия в случае магнетронной пленки приводит к формированию нанопористой губчатой структуры, а для ионно-лучевой пленки селективное травление не приводит к появлению развитой морфологии, что подтверждает ее однофазность. Последующий импульсный фотонный отжиг (ИФО) ионно-лучевых пленок дозами 145-216 Дж/см2 приводит к частичному распаду фазы Al3Si с формированием металлического алюминия и нанокристаллов кремния с размерами 50-100 нм в зависимости от дозы ИФО. Последующее травление образца, подвергнутого ИФО, ведет к получению развитой нанопористой структуры. Работа выполнена при поддержке Минобрнауки России в рамках государственного задания ВУЗам в сфере научной деятельности на 2017-2019 годы. Проект № 3.6263.2017/ВУ.

Abstract. This article describes the peculiarities of the phase composition and the electronic structure of composite Al0.75Si0.25 fi lms on a silicon substrate Si(100) obtained by magnetron and ion-beam sputtering. As a result of magnetron sputtering, Si nanocrystals with the sizes of ~25nm and metastable ordered solid solution Al3Si are formed in an Al matrix. Al3Si is characterized by a Рm3m cubic crystal structure with a primitive cell parameter a = 4.085 Å. The fi lms obtained by ion-beam sputtering contain only the ordered solid solution Al3Si. The Al3Si phase formation is accompanied by changes of the Al 3s-states density distribution. There is a linear dependence of the density-of-states distribution from energy instead of a parabolic dependence in the lower and middle part of the valence band (as in the case of pure metal). A similar effect was observed for Si 3s-states. In addition, the interaction between Al and Si atoms leads to the decrease of Al 3s-states density near the Fermi level. This is a result of electrons transitioning from Al atoms to the more electronegative silicon atoms. In case of magnetron fi lms, selective etching of aluminium leads to the formation of nanoporous sponge structure. And the selective etching of ion-beam fi lms does not cause well-developed morphology formation. Subsequent pulsed photon annealing (PPA) of the ion-beam fi lms (at 145–216 J/cm2) leads to the partial disintegration of Al3Si phase with the formation of metallic aluminium and silicon nanocrystals. The size of Si nanoparticles depends on PPA regimen and equals to 50–100 nm. Subsequent etching of the sample subjected to PPA leads to the formation of a nanoporous structure.

AbstractThe peculiarities of the phase composition and electronic structure of aluminum–silicon composite films near the Al_0.75Si_0.25 composition obtained by the magnetron and ion-beam sputtering methods on a Si(100) silicon substrate are studied using the X-ray diffraction techniques and ultrasoft X-ray emission spectroscopy. In addition to silicon nanocrystals of about 25 nm in size, an ordered solid solution corresponding to the previously unknown Al_3Si phase is formed in magnetron sputtering on a polycrystalline Al matrix. Films obtained by ion-beam sputtering of the composite target are found to be monophasic and contained only one phase of an ordered solid solution of aluminum silicide Al_3Si of the Pm3m cubic system with the primitive cell parameter a = 4.085 Å. However, subsequent pulsed photon annealing of the composite with different radiation doses from 145 to 216 J/cm^2 gives rise to the partial decomposition of the Al_3Si phase with the formation of free metallic aluminum and silicon nanocrystals with sizes in the range from 50 to 100 nm, depending on the pulsed photon radiation dose.

Based on experimental studies of solid-phase processes with photonic activation, a hypersonic mechanism was proposed for local excitation decay in crystals. This mechanism can occur in photocatalytic and cavitation processes, as well as at the step of detonation in explosives and in the structural rearrangements of crystals irradiated with light fluxes.

The effects of thermal annealing and pulsed photon processing on the structural transformations, Δ E effect, and internal friction in the amorphous Fe 79.3 P 18.2 V 2.5 alloy are studied. The results demonstrate that annealing and pulsed irradiation in a magnetic field have a significant influence on the magnetomechanical properties of the alloy, whereas pulsed irradiation in zero magnetic field has little effect on these properties. The irradiation effect is shown to depend on the structural transformations of the alloy at temperatures far below its crystallization temperature.

Изучен процесс кристаллизации аморфных сплавов системы Fe-P-V под действием импульсного фотонного облучения. Показано, что при кристаллизации сплавов помимо равновесных фаз α-Fe и (Fе,V) 3P выделяются две метастабильные фазы σ'-FeV и (Fе,V) 2P, которые, будучи менее устойчивыми при повышении температуры или энергии облучения, превращаются в равновесные и усиливают диффузионную подвижность атомов, приводя к росту фаз и уменьшению степени упрочнения.

The crystallization behavior of amorphous Fe–P–V alloys under pulsed irradiation is studied. The results demonstrate that the crystallized alloys contain not only the equilibrium phases α-Fe and (Fe,V)3P but also two metastable phases, σ′-FeV and (Fe,V)2P, whose stability decreases with increasing annealing temperature and irradiation energy. As a result, these phases transform into equilibrium phases, increasing the mobility of atoms and particle size and reducing the degree of hardening.