The process of X-ray diffraction on the X-112° Y-cut of a LiTaO3 crystal excited by surface acoustic waves (SAW) with a wavelength of Ʌ=4 μm was studied at a synchrotron radiation source in a scheme of a double-crystal X-ray diffractometer. The sinusoidal acoustic modulation of the crystal lattice leads to the appearance of diffraction satellites on the rocking curve; the number and intensity of satellites depend on the amplitude of the SAW. Analysis of X-ray diffraction spectra allowed us to determine the velocity (VSAW=3300 m/s) and amplitudes of the SAW. For the first time experimental investigations have demonstrated the presence of the power flow angle in the X-112° Y-cut of a LiTaO3 crystal, i.e., a situation where the direction of acoustic energy propagation (PFV) does not coincide with the direction of the SAW wave vector KSAW. The measured power flow angle was PFA=0.41°. This PFA value is important for designing acoustoelectronic devices in order to reduce acoustic signal losses.

The difference in the structure of titanium oxide thin films deposited on fused silica substrates and the Y-cut of a lithium niobate crystal is demonstrated. In both cases, the film is amorphous; however, an insignificant amount of rutile crystallites is observed in the film formed on the Y-cut of the lithium niobate crystal. It is shown that the electrical characteristics of the films depend not only on the material of the substrate, but, in the case of the lithium niobate substrate, also on the direction of an electric field. This is caused by the deformation of the substrate due to the inverse piezoelectric effect.

The SAW excitation and propagation on the X-112 degrees degrees Y-cut of a LiTaO3 crystal were studied using a triple-axis Xray diffractometer with a laboratory X-ray source. Simulation of X-ray rocking curves with the Takagi equation system enabled the determination of surface acoustic wave amplitudes on the crystal surface. The SAW excitation process in the frequency range of an acoustoelectronic device, determined by the excitation band or interdigital transducer structure, was studied.

Abstract X-ray diffraction by surface acoustic waves is investigated by the method of triple-crystal X-ray diffractometer on the laboratory source of X-ray radiation. This approach allows to determine the amplitudes of the surface acoustic waves (SAW) and to study the features of the diffraction process for different materials, to study the characteristics of fabrication of the structures of the interdigital transducers (IDT) for SAW excitation. The influence of the metallization coefficient of the IDT on the SAW excitation process is considered.

Results from studying the effect of an applied electric voltage on the Raman spectrum of graphene deposited on a lithium niobate crystal substrate with a ferroelectric domain structure are presented. The use of the principal component method for data processing in combination with correlation analysis made it possible to reveal the contribution to the change in the spectra associated with the linear deformation of the substrate due to the inverse piezoelectric effect. An effect of the graphene coating peeling was found. Furthermore, bending deformations of the graphene coating associated with the presence of a relief on the substrate were found. An analysis of the change in the spectra of graphene under the application of an electric voltage made it possible to determine the height of this relief.

The Auger electron spectroscopy method confirmed a high concentration of carbon atoms (~ 85 at.%) introduced into silicon by cold implantation of recoil atoms. Carbon atoms are concentrated in a thin (~ 5 nm) near-surface region of silicon. Annealing of such a structure did not reveal a noticeable diffusion of carbon, which prevents obtaining a layer of SiC with a thickness of more than a few nm. This problem was solved by using radiation-enhanced diffusion. This made it possible to control the distribution profiles of carbon atoms in a wide range. Annealing at 1150oC allowed obtaining layers of amorphous-crystalline SiC with a thickness of 50-150 nm. Higher annealing temperatures are required to obtain a single-crystal SiC film. Keywords: cold implantation, radiation-enhanced diffusion, silicon carbide, recoil atom, thin films.

X-ray diffuse scattering from the Ca3NbGa3Si2O14 (CNGS) crystal was measured with a triple axis X-ray diffractometer under the conditions of an external electric field. It is found that the nature of the intensity distribution of the asymmetrical part of diffuse scattering depends on the value of the applied electric field. This phenomenon is apparently associated with different piezoelectric characteristics of defect regions and the rest of the single crystal.

This paper presents the results of studying the effect of local changes in the composition of the LiNb1-xTaxO3 single crystal on the Raman spectra. Analysis of the crystal composition was carried out using laser ablation inductively coupled plasma mass spectrometry. Using statistical analysis of data on local changes in the chemical composition of a single crystal, it was found that Nb atoms partially replace Li vacancies. Using principal component analysis in combination with correlation analysis, the contribution of a change in the crystal composition to a change in the Raman spectra is determined. Found principal components correctly predict the shift of the Raman lines at transition of the crystal composition from niobate to lithium tantalate. During the formation of a mixed LiNb1-xTaxO3 crystal, at small amounts of Ta atoms replacing Nb, the substitution occurs in the cation sublattice.

The results of investigating the effect of an external electric field on the Raman spectrum of the Y-cut of a lithium niobate single crystal are presented. A change in the intensity and position of individual lines of the Raman spectrum that is associated with a change in the parameters of the crystal lattice due to the reverse piezoelectric effect is found. A change in the intensity and a shift in the spectral lines caused by local inhomogeneities of the lithium niobate single crystal have been also observed. In order to determine what contribution each of these effects makes to the change in the Raman spectra, the principal components analysis has been used in the analysis of experimental data.

The Auger electron spectroscopy method confirmed a high concentration of carbon atoms (~ 85 at. % ), introduced into silicon by cold implantation of recoil atoms. Carbon atoms are concentrated in a thin (~ 5 nm) near-surface region of silicon. Annealing of such a structure did not reveal a noticeable diffusion of carbon, which does not allow obtaining a layer of SiC with a thickness of more than a few nm. The solution to this problem was carried out by the use of radiation-stimulated diffusion. This made it possible to control the distribution profiles of carbon atoms in a wide range. Annealing at 1150 oC allowed to obtain layers of amorphous crystalline SiC with a thickness of 50-150 nm. Higher annealing temperatures are required to obtain a single-crystal SiC film.

The composition, structure and properties, as well as the current–voltage characteristics (CVCs) of nanostructured SZO films were studied. These films were fabricated by electron-beam evaporation of a layered structure consisting of two 50-nm-thick SiO2 films between which a Zn film with a thickness of 10–50 nm was deposited. Then these structures were annealed in air in the temperature range from 300 to 400°C with a step of 50°C for 30 min. Sandwiched (gold or platinum) electrodes were used. It was found that a granular structure with a grain size of 50–100 nm of SiO2 composition was formed on the sample surface after deposition. Upon annealing a crystalline cubic ZnO phase with the (111) orientation was formed in the sample. After annealing at 400°С ZnO clusters with characteristic exciton emission at a wavelength of 384 nm were detected in the sample; the grain size on the sample surface increased to 100–200 nm. CVCs with a hysteresis were obtained for SZO films annealed at 400°C.

The possibilities are presented of X-ray diffraction methods for studying the propagation of surface acoustic waves (SAWs) in solids, including diffraction under total external reflection conditions and Bragg diffraction, using acoustically modulated X-ray multilayer mirrors and crystals. SAW propagation was studied using both meridional and sagittal diffraction geometries where the SAW wavevectors and X-ray photons are collinear or perpendicular, respectively. SAW propagation in a crystal leads to sinusoidal modulation of the crystal lattice and the appearance of diffraction satellites on the rocking curve. The intensities and angular positions of these diffraction satellites are determined by the SAW wavelength, amplitude and attenuation. Therefore, diffraction methods allow the analysis of the SAW propagation process and determination of SAW parameters. The influence of X-ray energy on diffraction by acoustically modulated crystals is studied for the first time. It is shown that changes in the X-ray energy can change the angular region where diffraction satellites exist under conditions of total external reflection. By contrast, in the Bragg diffraction region changes in the X-ray photon energy lead to changes in the X-ray penetration depth into the crystal and redistribution of the diffracted intensity among diffraction satellites, but do not change the angular divergence between diffraction satellites on the rocking curve. It is also shown that, in X-ray diffraction on acoustically modulated crystals on a number of successive reflections, a decrease in interplanar spacing leads to an increase in the number of diffraction satellites and a redistribution of diffracted radiation between them.

We report direct optical reading of resistive switching in an amorphous TiO2 film. Changing TiO2 film conductivity under an applied electric field causes a change in the film reflection coefficient. To find this phenomenon, a sample with Al electrodes deposited on an amorphous TiO2 film in the form of an interdigital transducer was used. The experimental characteristic of a device shows a hysteresis of the reflection coefficient repeating the change in resistance under an applied electric field.

Представлены результаты исследования зависимости интенсивности лазерного излучения, дифрагированного на структуре электродов, от состояния резистивно-переключаемой пленки аморфного TiO2. Обнаружено, что форма зависимости интенсивности дифракционных порядков, так же как и зависимость сопротивления, характеризуется наличием петли гистерезиса. Предложена модель, согласно которой изменение интенсивности дифракционных порядков связано с изменением коэффициента отражения аморфной пленки TiO2 вследствие изменения проводимости пленки в результате резистивного переключения.

Ferroelectric LiNb1-xTaxO3 solid solutions with various Nb/Ta ratio were grown from the melt by the Czochralski method. The exact composition of the grown crystals was determined by inductively coupled plasma atomic mass spectrometry. The dependence of the crystal composition on the composition of the initial melt was obtained and explained by a wide separation between the phase boundaries of the liquid and solid phases on the LiNbO3-LiTaO3 phase diagram. Using high-resolution X-ray diffraction, the parameters a and c of a crystal unit cell were determined (LiNb0.88Ta0.12O3: a = 5.1574 Å and c = 13.8498 Å). Further, the Curie temperature TC of the crystals was measured using the differential scanning calorimetry technique. TC was found to depend on the composition of the crystals that allowed conditions for the monodomainization of the grown crystals to be defined (LiNb0.88Ta0.12O3: TC = 1102°C; LiNb0.33Ta0.67O3: TC = 794°C). Finally, the velocity of surface acoustic waves was determined by scanning electron microscopy and X-ray diffraction techniques (YZ-cut of a LiNb0.88Ta0.12O3 crystal: V = 3440 m s-1).

The effect of photon annealing on deformation in the crystal structure of boron doped Cz-Si wafers has been studied using triple crystal X-ray diffraction. Conventional annealing of the entire surface of double-side polished silicon wafers with halogen lamps (photon annealing mode) and rapid thermal annealing produce compression deformation. Annealing with special phototemplate providing for local annealing of multiple separated wafer areas (local photon annealing mode) at relatively low wafer temperatures (less than 55 °C) produces tensile deformation. This effect however is not observed if the reverse side of the annealed wafer contains a mechanical gettering layer. A mechanism explaining the experimental results has been suggested and can be used for the synthesis of charge pumps in photoelectric converter structures.

The effect of photon annealing on the occurrence of deformations in the crystal structure of boron−doped silicon wafers produced by the Czochralski (Cz−Si) was studied by the method of triple−X−ray diffraction. It was found that the traditional annealing of silicon wafers with polished surfaces on both sides by halogen lamps in Photonic Annealing (PA) and rapid thermal annealing modes (RTA) leads to compression deformation. The same process with the use of original photo− mask, which allows local processing produces multiple, spatially separated regions of the plate produced by Lосаl Photonic Annealing (LPA) at relatively low temperatures (less than 55 °C), gives rise to a tensile strain. This established effect is not observed if on the back side of the plates there is mechanical gettering layer. The mechanism explaining the experimental results can be used in the formation of the charge pump in the structure of the photo electric converters (PEC).