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.

Cu2ZnGeS4 single crystals were grown by chemical vapor transport reaction method. Their composition and crystal structure were determined. It was shown that the obtained single crystals crystallize in a tetragonal structure. The band gap of the obtained single crystals was determined basing on transmission spectrum in the region of the absorption edge in temperature range of 10-320 K. It was found that band gap width increases with decreasing of temperature. Keywords: Bridgman method, single crystals, crystal structure, transmission spectrum, band gap.

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.

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.

Методом химических газотранспортных реакций выращены монокристаллы соединения Cu2ZnGeS4. Определен их состав и кристаллическая структура. Показано, что выращенные монокристаллы кристаллизуются в тетрагональной структуре. По спектрам пропускания в области края собственного поглощения в интервале температур 10-320 K определена ширина запрещенной зоны указанных монокристаллов. Установлено, что ширина запрещенной зоны с понижением температуры возрастает. Ключевые слова: монокристаллы, кристаллическая структура, спектры пропускания, ширина запрещенной зоны.

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.

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.

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.

Mn 1.5 AgIn 8.0 S 14 single crystals were grown by the Bridgman directed melt crystallization method. Crystals composition and structure were determined. It was found that these single crystals crystallize in a cubic spinel structure with a lattice constant a = 10.765 ± 0.005 A. The width of the band gap of Mn 1.5 AgIn 8.0 S 14 single crystals was estimated from the transmission spectra in the region of the edge of its intrinsic absorption in the temperature range of 10—320 K. The band gap width decreases with the temperature increasing and a functional approximation of this dependence was obtained.

FeIn2S3.6Se0.4 single crystals are grown by planar crystallization of the melt (the vertical Bridgman method). The composition and crystal structure of the crystals are determined. It is established that the single crystals crystallize with the formation of the cubic spinel structure. From the transmittance spectra in the region of the fundamental absorption edge, the band gap of the single crystals is determined. Thermal expansion of the FeIn2S3.6Se0.4 single crystals is studied by the dilatometric technique in the temperature range from 80 to 550 K, and the coefficients of thermal expansion are determined. From the coefficients of thermal expansion determined, the Debye temperatures and the root-mean-square (rms) dynamic displacements of atoms are calculated. It is shown that, as temperature is elevated, the Debye temperatures decrease and the rms dynamic displacements of atoms increase. Magnetic studies show that the FeIn2S3.6Se0.4 single crystals are paramagnetic materials at temperatures down to 12.4 K.

Mn1.5AgIn8.0S14 single crystals were grown by Bridgman directed melt crystallization. Their composition and crystal structure were determined. Single crystals crystallized in the cubic spinel structure with lattice constant a = 10.765 ± 0.005 Å. The band-gap width of Mn1.5AgIn8.0S14 single crystals was estimated from transmission spectra near the intrinsic absorption edge in the temperature range 10–320 K and decreased with increasing temperature. A function approximating this dependence was obtained.

Cu2ZnGeSe4 and Cu2ZnSnSe4 and Cu2ZnGe1 –xSnxSe4-alloy crystals are grown by the Bridgman method (vertical variant). The composition and structure of the crystals are determined. It is established that both the initial compounds and their alloys crystalize with the formation of tetragonal structure. The unit-cell parameters a and c of the crystals are calculated, and the dependences of these parameters on the composition of the alloys are constructed. It is shown that, under variations in the composition parameter x, the parameters a and c vary in accordance with Vegard’s law. The thermal conductivity of the Cu2ZnGeSe4 and Cu2ZnSnSe4 compounds and Cu2ZnGe1 –xSnxSe4 alloys is measured in the temperature range 300–600 K. It is found that the thermal conductivity varies with x, with a minimum for the medium composition.

Методом Бриджмена выращены монокристаллы соединений In2S3, AgIn5S8 и твердых растворов (In2S_3)x(AgIn5S_8)1-x, определен их состав и структура. Установлено, что как исходные соединения, так и твердые растворы на их основе кристаллизуются в кубической структуре шпинели. Рассчитаны параметры элементарной ячейки указанных монокристаллов и построена их концентрационная зависимость. Показано, что в исследуемой системе выполняется закон Вегарда. Исследованы спектры пропускания в области края фундаментального поглощения при комнатной температуре и определена ширина запрещенной (Eg) для указанных монокристаллов. Показано, что Eg с составом х изменяется с отклонением от линейности. Ключевые слова: монокристаллы, кристаллическая структура, твердые растворы, спектры пропускания, ширина запрещенной зоны.