Antireflection coatings (ARCs) increase the absorption of light and, therefore, the conversion efficiency of solar cells. Mullite was chosen as the ARC material for a silicon (Si) solar cell and was synthesized by melting a charge consisting of a mixture of Al2O3 and SiO2 at a component concentration of 75 and 25 wt.

Polycrystals of solid solutions MnxFe1_xIn2S4 were prepared by the two-temperature method. The degrees of phase transformations were defined by differential thermal analysis (DTA), and a phase diagram of the MnIn2S4-FeIn2S4 system was obtained. The phase diagram is described by a narrow crystallization interval and classified as type I according to the Roozeboom classification. Single crystals of solid solutions MnxFe1_ xIn2S4 were grown by vertical gradient freeze method of synthesized polycrystals. The elemental composition of the obtained samples was in good agreement with the calculated composition. The structure was defined by XRD. Prepared samples had a cubic structure, and the parameters of the elementary cell were calculated by the method of least squares. The thermal linear expansion coefficient was investigated in the temperature range T = 80-550 K. Based on the obtained data, the values of the Debye temperature and the root-mean-square atomic shifts were determined, and their concentration dependencies are presented. The thermal conductivity was studied using the absolute method in the temperature range T = 300-550 K. The form of the concentration dependence, the contribution of the lattice and electronic components, and an analytical dependence of the thermal conductivity for the entire range of solid solution were established.

Nickel nanoparticles were synthesized at room temperature by a one-step method of chemical reduction of Ni ions from NiCl2∙6H2O using NaBH4. The microstructure of the nanoparticles was studied by x-ray diffraction, Raman spectroscopy, and scanning and transmission electron microscopy. An analysis of x-ray diffraction and Raman spectroscopy data showed that the obtained nanoparticles had the cubic metallic Ni structure with a crystallite size (coherent scattering region) of 3–6 nm. Studies of the morphology indicated that the Ni nanoparticles were spherical in shape and in contact with each other to form large agglomerates of nanograins.

In this work, the optical properties of nanocrystalline CdS films in the initial state and after ion-plasma treatment have been studied. The chemical bath deposition technique was used to prepare CdS films with thickness 80-115 nm on glass substrates. The ion-plasma treatment was carried out in argon plasma in a high-density low-pressure radio frequency inductively coupled plasma reactor at an argon ion energy of 25 eV for 30-50 s. It has been established that ion-plasma treatment leads to a decrease in film thickness by 10-15% of the initial one and the formation of new nanostructures on its surface. The results showed that the sizes of coherent scattering regions during plasma treatment decreased for a series of studied samples from 8.2-10.0 nm to 6.3-7.7 nm. This led to an increase in the band gap energy of the for nanocrystalline CdS films from 2.53-2.78 eV to 2.95-3.11 eV.

AgIn7S11 single crystals are herein grown by the vertical Bridgman method. The composition of the obtained single crystals is determined by X-ray microprobe analysis as well as the crystal structure – by X-ray diffraction analysis. It is shown that the obtained single crystals are crystallized in the cubic spinel structure. Using transmission spectra in the tem- perature range 10–320 K we determined the band gap of these single crystals and plotted its temperature dependence. This dependence is similar to that of the majority of semiconductor materials, namely, Eg increases with decreasing the tempera- ture. We showed the agreement of the calculated and experimental values.

AgIn 7 S 11 single crystals are herein grown by the vertical Bridgman method. The composition of the obtained single crystals is determined by X-ray microprobe analysis as well as the crystal structure – by X-ray diffraction analysis. It is shown that the obtained single crystals are crystallized in the cubic spinel structure. Using transmission spectra in the tem- perature range 10–320 K we determined the band gap of these single crystals and plotted its temperature dependence. This dependence is similar to that of the majority of semiconductor materials, namely, E g increases with decreasing the tempera- ture. We showed the agreement of the calculated and experimental values.

IR reflectance spectroscopy at 50–450 cm –1 was used to study homogeneous monocrystals of (FeIn 2 S 3 ) x ∙(In 2 S 3 ) 1– x grown by the method of direction melt crystallization (vertical Bridgman method). The frequencies of the transverse (ω TO ) and longitudinal optical phonons (ω LO ) as well as their damping coefficients were determined. Concentration dependence curves were constructed for these parameters and their behavior was established.

Homogeneous single crystals of CuIn11S17 with 14 mm in diameter and 40 mm in length were grown by directional crystallization of the melt (vertical Bridgman method). The composition and structure of the obtained single crystals were determined by the X-ray microanalysis and the X-ray diffraction analysis, respectively. It is shown that the obtained single crystals crystallize in a hexagonal structure. The anisotropy of thermal expansion was investigated for single crystals oriented parallel and perpendicular to the main crystal axis in the temperature range of 120-600 K. It was found that anomalies of thermal expansion are observed in the indicated single crystals oriented parallel to the main crystal axis.

Large-block crystals of FeIn2S4 and MnIn2S4 ternary compounds and MnxFe1–xIn2S4 solid solutions are grown by directional crystallization (horizontal Bridgman method). The structures of the obtained crystals are determined by x-ray diffraction analysis. Both the starting compounds and the solid solutions based on them are shown to crystallize in the cubic spinel structure. IR reflection spectra in the range 50–500 cm–1 of crystals of FeIn2S4 and MnIn2S4 ternary compounds and FexMn1–xIn2S4 solid solutions are studied. The frequencies of transverse (ωTO) and longitudinal (ωLO) optical phonons are determined. The concentration dependences of these parameters are plotted. The nature of their behavior is established.

Методом Бриджмена из расплава выращены однородные монокристаллы CuIn7Se11 диаметром ~ 14 мм и длиной ~ 40 мм. Определен состав и структура полученных монокристаллов. Показано, что полученные монокристаллы кристаллизуются в гексагональной структуре. На ориентированных монокристаллах параллельно и перпендикулярно главной оси кристалла c исследована анизотропия теплового расширения и теплопроводности в интервале температур 80-650 K. Установлено, что на указанных монокристаллах, ориентированных параллельно главной оси кристалла наблюдаются аномалии теплового расширения и теплопроводности. Ключевые слова: метод Бриджмена, монокристаллы, кристаллическая структура, тепловое расширение, теплопроводность.

Large-block crystals of FeIn 2 S 4 and MnIn 2 S 4 ternary compounds and MnxFe 1– x In 2 S 4 solid solutions are grown by directional crystallization (horizontal Bridgman method). The structures of the obtained crystals are determined by x-ray diffraction analysis. Both the starting compounds and the solid solutions based on them are shown to crystallize in the cubic spinel structure. IR reflection spectra in the range 50–500 cm –1 of crystals of FeIn 2 S 4 and MnIn 2 S 4 ternary compounds and Fe x Mn 1– x In 2 S 4 solid solutions are studied. The frequencies of transverse (ω TO ) and longitudinal (ω LO ) optical phonons are determined. The concentration dependences of these parameters are plotted. The nature of their behavior is established.

Homogeneous CuIn7Se11 single crystals with a diameter of ~14 mm and length of ~ 40 mm have been grown from the melt using the Bridgman method. Composition and structure of the obtained single crystals have been defined. It was shown that the obtained single crystals crystallized in a hexagonal structure. The anisotropy of thermal expansion and thermal conductivity in the temperature range of 80-650 K has been investigated on oriented single crystals in parallel and at right angle to the main crystal axis c. Abnormal thermal expansion and thermal conductivity were observed on the single crystals oriented in parallel to the main crystal axis. Keywords: Bridgman method, single crystals, crystalline structure, thermal expansion, thermal conductivity.

On homogeneous monocrystals of solid solutions (FeIn2S4)х·(In2S3)1–х, grown by the method of directional melt crystallization (vertical Bridgman method), IR reflection spectra in the frequency range of 50—450 cm–1 were studied. The frequencies of transverse (ωTO) and longitudinal (ωLO) optical phonons, as well as their damping coefficients, were determined. The concentration dependences of the mentioned parameters were constructed and the nature of their behavior was established.

The thermal expansion and thermal conductivity of In2S3 and AgIn5S8 single-crystal compounds and (In2S3)x(AgIn5S8)1 – x alloys grown by the Bridgman method are studied. It is established that the thermal-expansion coefficient linearly varies under changes in the composition parameter x and the thermal conductivity has a minimum for the equimolar composition. From experimental data on the thermal-expansion coefficient, the Debye temperature and the root-mean-square (rms) dynamic displacements of atoms are calculated. It is shown that, as the content of Ag atoms in the alloys is increased, the Debye temperature increases and the rms dynamic displacements of atoms in the crystal lattice decrease.

Single crystals of solid solutions (In2S3)x⋅ (AgIn5S8)1–x were grown by the method of directional crystallization of the melt (Bridgman method). Studies of the elemental composition and crystal structure of these single crystals have been carried out. On the basis of solid solutions (In2S3)x⋅ (AgIn5S8)1–x, photosensitive structures have been created for the first time and the photoelectric properties of these structures have been determined. The possibility of using the created structures as broadband photoconverters of optical radiation is shown.

The phase diagram of the Cu2CdSnS4–Cu2ZnSnS4system was constructed using data on differential thermal, X-ray phase and microstructure analysis methods. The diagram can be attributed to the first type according to the Rosebohm classification. The Cu2CdSnS4–Cu2ZnSnS4 solid solution single crystals were grown by chemical vapor transport using iodine as a transport agent. Their structure and unit cell parameters as well as compositional dependences of lattice parameters, pycnometric, X-ray densities and microhardness were determined. It was found that the Vegard's law is fulfilled in solutions studied.

Herein, single crystals of compounds In2S3, AgIn5S8 and solid solutions (In2S3)x·(AgIn5S8)1–x were grown by directional crystallization. The composition of the obtained single crystals was determined by microprobe X-ray spectral analysis. It is found that the content of the components in the grown single crystals is in satisfactory agreement with the specified composition in the initial charge. The structure of the obtained materials was determined by the X-ray method. It is shown that both the initial compounds and the solid solutions based on them were crystallized in the cubic structure of the spinel. The unit cell parameters of the In2S3, AgIn5S8 compounds and the solid solutions based on them, which vary linearly with the composition x, were calculated by the least squares method. The density was determined by the pycnometric method, and the microhardness of the In2S3 and AgIn5S8 compounds and the (In2S3)x·(AgIn5S8)1–x solid solutions was determined by the Knoop method. It is shown that the density, like the unit cell parameter, changes linearly with the composition x, but the dependence of microhardness on the x parameter has a maximum for x = 0.4. Using differential thermal analysis (DTA), the temperatures of phase transformations were determined and the phase diagram of the In2S3–AgIn5S8 system was constructed, which is characterized by a small crystallization interval and belongs to type III according to the Rosebom classification. The curves of liquidus and solidus are concave to the abscissa axis and have a common point.

The reliability of computer-based information systems is largely determined by the reliability of the developed application software. The failure rate of its computer program is considered as an indicator of the reliability of the application software. To determine the expected reliability of the application software planned for the development (until writing the code of a program), the model is proposed that uses some parameters of the future computer program, data on the influence of various factors on its reliability, and further testing of the program. The model takes into account the field of software application and computer processor performance. The process of model parameters obtaining is analyzed., It is possible by use of proposed model to determine the predicted failure rate of the planned application computer program, and then the reliability of the computer-based information system as a whole. If necessary, the measures can be developed to ensure the required level of reliability of the computer-based information system.

Исследованы тепловое расширение и теплопроводность монокристаллов соединений In2S3, AgIn5S8 и твердых растворов (In2S3)x· (AgIn5S8)1-x, выращенных методом Бриджмена. Установлено, что коэффициент теплового расширения с составом (с величиной x) изменяется линейно, теплопроводность имеет минимум при эквимолярном составе. По экспериментальным значениям коэффициента теплового расширения рассчитаны температуры Дебая и среднеквадратичные динамические смещения. Показано, что с увеличением содержания в твердых растворах атомов серебра температура Дебая увеличивается, а среднеквадратичные динамические смещения атомов в кристаллической решетке уменьшаются. Ключевые слова: In2S3, AgIn5S8, тепловое расширение, теплопроводность, температура Дебая, среднеквадратичное смещение атомов.