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Textured ZnO films obtained on amorphous substrates using the ion-beam sputtering method are studied. X-ray diffraction and atomic-force microscopy methods show that the resulting films have a polycrystalline structure immediately after deposition. It is established that further annealing of the samples in the temperature range from 200°C to 500°C results in recrystallization, which leads to changes in the grain size and surface roughness. A dependence of the crystallization intensity on the deposition conditions is found, which is related to the number of defects in the unannealed films. In films with an initially more perfect structure, heat treatment at 500°C results in the growth of grains by more than 2 times and a decrease in the roughness by ∼40%.

In this work, we have prepared ZnO, NiO, and nanocomposites ZnO–NiO thin films elaborated by the chemical method of spray pyrolysis on glass substrates at a temperature of 480°C. The prepared samples have been analyzed by means of the X-ray diffraction (XRD), UV-visible spectrophotometry, micro-Raman and m-lines spectroscopies techniques. The structure of the thin ZnO films is hexagonal of the wurtzite type with a preferential orientation along the axis (002). The size of the crystallites, deduced from the XRD measurements, varies between 25 and 43 nm. The NiO films crystallize in the cubic structure with the size 4 nm of the crystallites. The micro-Raman study confirms the XRD results showing the presence of the vibrational modes characteristics of the wurtzite structure of ZnO and the cubic structure of NiO. The obtained films have an optical transmission varying from 60 to 95% in the visible region. The forbidden optical band energies, deduced from the transmittance, are 3.28 and 3.89 eV for the ZnO and NiO films, respectively. The optical waveguiding measurements carried out on pure ZnO and ZnO–NiO films show single-guided modes behavior (TE0 and TM0). These measurements have allowed deducing the thickness and the refractive index values which are respectively 250 nm and 1.89 for ZnO, 165 nm and 1.80 for ZnO–NiO thin films.

The absorption Mossbauer spectroscopy on 119Sn impurity centers shows that germanium atoms in the structure of amorphous and polycrystalline Ge2Sb2Te5 films have different local symmetries (tetrahedral in the amorphous phase and octahedral in the crystalline). By emission Mossbauer spectroscopy on 119mSn impurity centers formed after the radioactive decay of 119Sb or 119mTe parent atoms, tin antisite defects at antimony and tellurium sites of crystalline Ge2Sb2Te5 films are identified.

In the present report, influence of annealing temperature variations on the optical, morphological, and structural properties of chemically deposited nanocrystalline zinc-selenide thin films is studied employing an X-ray diffractometer, scanning electron microscope, and UV spectroscope. As-synthesized and annealed films exhibit nanocrystalline nature with cubic structure. The result shows that ZnSe thin films contain spherical particles that are composed of nanocrystals ranging from 3 to 7 nm crystallite size. The SEM studies reveal that the inter-crystalline spaces have been found to be reduced with an increase in grain size as annealing temperature increases. The EDS data reveal that the obtained thin films are rich in selenium. However, thermal annealing assisted to reduce the non-stoichiometric nature of the films by reducing selenium content that was found to be reduced with a rise in annealing temperature. The reduction in strains and dislocation density was observed after the annealing process. The band-gap energy was found to be raised from 2.56 to 2.76 eV with a rise in annealing temperature. The transmittance of more than 80% was recorded by as-synthesized and annealed films as well.

In this work, we have prepared the undoped and Al-doped ZnO thin films by a homemade spray pyrolysis method at 450°C onto glass substrates. The X-ray diffraction patterns of undoped ZnO and aluminized zinc-oxide (AZO) thin films exhibit hexagonal wurtzite crystal structure with high crystalline quality, the crystallite size is nanometric. The morphology of the undoped and Al-doped ZnO thin films also indicate that all samples have a nanoscale grain size around 50 nm, and the microstructure of ZnO films is highly influenced by the aluminum doping. The two films are characterized by UV-visible spectrophotometry showing that the films have a whole optical transmission above 85% in the visible range. The composition of our films is obtained by energy dispersive spectrum, confirmed by Auger electron spectroscopy (AES) and by Rutherford back-scattering spectrometry (RBS) techniques.

Films of the composition Ba0.8Sr0.2TiO3 (BST 80/20) are synthesized on a silicon substrate by the method of the high-frequency sputtering of a polycrystalline target. The results of investigations of the film composition, the electrophysical properties of capacitor structures based on them, and the dependence of these properties on the material (Al, Cu, Ni, Cr) of the upper electrode are presented.

In this study, we reported facile sonochemical synthesis of CuS nanoparticles by using CuCl2 and Na2S in aqueous medium without using any organic solvent and surfactant. Structural characterization of synthesized product using X-ray diffraction study revealed the formation of hexagonal structure of CuS in covellite phase. Crystallite size of ~13 and ~11 nm were determined using Debye–Scherrer and Williamson–Hall methods, respectively. Field emission scanning electron microscopy micrographs revealed the particulate morphology of CuS nanostructures. The optical properties of CuS nanoparticles were investigated by ultra violet and visible (UV-Vis), photoluminescence (PL), and Fourier transform infrared spectroscopy. The band gap was calculated by Tauc’s relation and found to be 3 eV. The PL spectrum showed a strong green emission at wavelength 505 nm. The electrical conductivity of CuS nanoparticles was found to be in semiconducting range, i.e. 550 S/cm. Impedance analysis of CuS nanoparticles revealed 7.55 MHz as the resonant frequency.

Cu2ZnSnS4 is suitable for high-performance thin-film solar cell because of its high absorbance coefficient, presence of non-toxic elements, excellent optoelectronic properties, and a near-perfect direct band gap. The effect of thermal annealing time (1–4 h) on the optical, morphological, and structural properties of Cu2ZnSnS4 coated through a simple solution processable method has been studied in the present work. All the CZTS films are crystalline in nature with kesterite structure as shown by X-ray diffraction studies. Crystallite size, strain, and dislocation density were calculated. However, no notable changes in these parameters were obtained by varying the annealing time in the above range. Field emission scanning electron microscopy images show good quality compact films with particle size in the order of 10–15 nm. Absorption spectroscopy results show an optical band gap of 1.46 eV. Raman spectroscopy was used to check binary or ternary phases present. It shows that the impurity phase decreases and the pure Cu2ZnSnS4 phase was obtained by increasing the annealing time to 3 and 4 h.

Crystal of zinc-doped In0.6Se0.4 was successfully grown by direct vapour transport (DVT) method. Grown In0.6Se0.4:Zn crystal has been characterized by energy dispersive X-ray (EDAX) and powder X-ray diffractometer (XRD) techniques for compositional and micro-structural analysis, respectively. The EDAX spectra represent the grown In0.6Se0.4:Zn crystal enriched with excess indium doped with Zn, which consecutively shows enhanced n-type conductivity. The powder XRD spectrum signified that the grown sample was crystalline and had hexagonal structure. The micro-structural parameters: average crystallite size, average lattice strain, dislocation density, and domain population were determined from powder XRD spectra. The thermoelectric properties such as Seebeck coefficient (S), electrical resistivity (σ), and thermal conductivity (κ) were measured in the temperature range of 313 to 368 K. Grown In0.6Se0.4:Zn crystal reported Seebeck coefficient (S) as high as –548 μV K–1 and figure of merit of 1.14 at 368 K.

Nanostructured tin dioxide powders were synthesized successfully through a sol–gel route. Subsequent thermal treatment was carried out at different temperatures to obtain the SnO2 powders in crystal form. The identification and evolution of the crystal structure were determined by analyzing the results of the X-ray diffraction (XRD) for the powder products. Based on these results, the influences of the post-annealing temperatures on both the crystallinity and the crystallite size were investigated and analyzed. The diffuse reflectance spectra were measured for insight into the optical band gap and optical transition in the resulting powders. The results of the diffuse reflectance spectroscopy (DRS) revealed that all the obtained nanocrystalline powders exhibit direct allowed transitions. The change in the width of the optical band gap was discussed and analyzed in lines with the variation in the post-annealing temperature. The resulting SnO2 powders were compressed into dense pellets for the electrical measurements. These measurements were carried out in an evacuated medium at different working temperatures ranging from 77 to 300 K. The effects of the working and the post-annealing temperatures on the DC electrical conductivity were discussed and analyzed exhaustively for all the pellet samples.

For this study, titanium dioxide (TiO2) thin films were deposited on glass substrates at room temperature by the RF magnetron sputtering technique. The preparation parameters that offer better control and reproducibility of film fabrication were first optimized. Then, the effects of post-deposition annealing temperature at 350, 450, and 550°C on the microstructure, surface morphology, and optical properties of the prepared films were investigated using X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV–Visible (UV–Vis) spectrophotometry. Interestingly, XRD analysis shows that as-deposited and annealed TiO2 film possess anatase crystal structure only with a preferential orientation along the (101) plane. The intensity of the (101) diffraction peak and crystallite size are found to increase with increasing annealing temperature, which indicates an improvement in the crystallinity of the films. Raman spectra confirm that all samples possess anatase phase and the crystallinity is enhanced with increasing thermal annealing. From the analysis of SEM and AFM images, it is revealed that the heat treatment significantly affects the morphology, grain size, and surface roughness of the TiO2 films. The UV–Vis spectroscopy analysis shows that as-deposited TiO2 thin film is highly transparent in the visible region with an average transmittance about 84%, whereas the transmission decreases slightly with an increase in annealing temperature. Moreover, the optical band gap energy shows a red shift with increasing the annealing temperature.

The effect of the Gd concentration on the temperature and pressure coefficients of the resistance of thin polycrystalline films of Sm1 – xGdxS solid solutions, where x = 0, 0.05, 0.1, 0.2, 0.33, and 0.5 is studied. The films are grown by explosive evaporation in vacuum of powders of the initial compounds and sedimentation of the latter from the gas phase onto glass substrates. The dependences of the temperature α and pressure β coefficients of the resistance are determined, as well as their ratios γ on the Gd concentration x in the system of SmS–GdS solid solutions, based on which the optimum compositions for fabricating thin-film piezoresistors and baroresistors are determined.

In this study, the effect of deposition time on physical properties of tin monosulphide films capped by polyvinyl alcohol was investigated. Chemical bath deposition technique was used to deposit Polyvinyl alcohol capped SnS films on cleaned glass substrates and the deposition was carried out at four different times varying from 45 to 90 min. The X-ray diffraction study revealed that the deposited layers were polycrystalline in nature with (040) as the preferred plane. Single phase SnS was observed in the layers grown at a deposition time of 90 min while the other layers had secondary phases of Sn and S. The XRD data was also used to determine various parameters such as crystallite size, dislocation density, lattice strain, stacking faults and inter planar spacing. Raman measurements exhibited same structural phases, consistent with the XRD observations. The surface morphology of the layers was initially uneven and become uniform at 90 min deposition time. Fourier transform infrared spectra, confirmed the presence of SnS and PVA in the films. Optical studies revealed high optical absorption coefficient for all the films with a shift in optical band gap value compared with the bulk value.

Depending on the choice of the technology for producing CuInxGa1 – xSe2 films, a spread in the electrophysical and photoelectric parameters of photoconverters is observed, which is primarily related to the microstructure formed in the films and their phase composition. The investigation of phase-separation processes and the formation of a single-phase CuInxGa1 – xSe2 film is a key element in fabricating high-quality absorbing layers. In the study, CuIn0.95Ga0.05Se2 thin films are obtained by the two-stage selenization method of previously synthesized copper−indium−gallium layers of different thickness in the temperature range of 350°C ≤ T ≤ 550°C. The surface morphology, chemical composition, and structure of the synthesized CuIn0.95Ga0.05Se2 films are investigated via scanning electron microscopy, X-ray powder diffraction, and X-ray fluorescence. It is established that the synthesized films are polycrystalline and have a developed surface with an average crystallite size of 50–140 nm. On the basis of statistical analysis of the electron-microscopy data, the lowest temperature of the onset of the selenization process and the smallest required thickness of the metal layer for the formation of a continuous thin film CuIn0.95Ga0.05Se2 are determined. The obtained films can be used as the active photosensitive layer in highly efficient solar-radiation converters.

Metallic nanoparticles are promising objects of study, since their properties greatly differ from the properties of bulk material. In analyzing nanoparticles, it is important to investigate their size, stability, structural features, and spatial arrangement. In this study, initial and annealed silver nanoparticles from ∼2 to 10 nm in size formed on a carbon substrate by vacuum thermal evaporation are investigated by high resolution transmission electron microscopy and their shape and structure are classified. The examined nanoparticle types include faceted ellipsoid ones with a polycrystalline structure, coarse ones with a single-crystal structure and twins, icosahedral and decahedral ones with multiple twinning, and fine single-crystal nanoparticles smaller than 3.5 nm. It is established that, after annealing, the total number of nanoparticles decreases by a factor of ~1.3, the number of fine nanoparticles almost halves, and the fraction of nanoparticles with icosahedral and decahedral cross sections increases by a factor of ~1.5. It is shown that nanoparticles smaller than 5 nm become unstable already after a few seconds of exposure to high-energy electrons. For fine single-crystal nanoparticles smaller than 3.5 nm, the average crystal-lattice parameter is found by precise determination of the centers of atomic columns in their images and calculation of the local distances between atoms located in the mutually perpendicular (200) and (022) planes. It is shown that, in such nanoparticles both before and after annealing, there are no noticeable crystal-structure distortions and their lattice parameter is similar to the value characteristic of bulk silver.

The properties of gallium-oxide films produced by the radio-frequency magnetron-assisted sputtering of a β-Ga2O3 target with deposition onto sapphire substrates are studied. The as-deposited gallium-oxide films are polycrystalline and contain crystallites of the α and β phases. Exposure to oxygen plasma does not bring about the appearance of new crystallites but makes crystallites several times larger in average dimensions in the substrate plane. After annealing at 900°C, the crystallite size becomes twice as large as that in the unannealed film. The films not subjected to thermal annealing exhibit a high resistance at 20°C. In the range of 50–500°C, the conductivity of the samples (G) only slightly depends on temperature (T) and, as T is elevated further, exponentially increases with the activation energy 0.7–1.0 eV. After annealing of the films in argon at 900°C (30 min), the conductivity G starts to sharply increase at T ≈ 350°C. In the dependence of lnG on T –1, a maximum in the range of 470–520°C and a portion of decreasing conductivity at higher temperatures are observed. The unusual temperature dependence of the conductivity after annealing is attributed to a change in the structure and phase composition of polycrystalline gallium-oxide films and, possibly, to some effects at the surface. The structures produced on insulating substrates are solar blind in the visible wavelength region and sensitive to radiation in the ultraviolet region (222 nm).

Polycrystalline lead-sulfide (PbS) films doped with calcium are synthesized on sitall and glass substrates by chemical bath deposition with the use of thiocarbamide and a CaCl2 additive at concentrations of up to 5 mM. Introduction of the CaCl2 additive into the reaction solution greatly prolongs the induction period of the process of synthesis. The thicknesses of the PbS and PbS(Ca) films are, correspondingly, 200 and 150 nm at an average crystallite dimension of ~100 nm. The maximum calcium content in the films is 0.06 at % for layers on sitall substrates and 0.11 at % for layers on glass substrates. Doping with calcium does not influence the crystal structure of lead sulfide (the cubic B1 structure, space group Fm3 $$\bar {m}$$ ) but brings about an increase in the crystal-lattice period from a = 0.59343(2) nm to a = 0.59413(1) nm, an increase in microstrains, and partial ordering of the crystallites forming the film. Upon the introduction of calcium, the band gap decreases from Eg = 0.40 eV at 295 K (0.38 eV at 90 K) to Eg = 0.38 eV (0.37 eV). The introduction of up to 5 mM of CaCl2 into the reaction mixture increases the voltage–power sensitivity of the films by a factor of ~1.7, which is attributed to oxygen-containing compounds formed in the films as a result of the increase in the induction period of the process of synthesis.

A new method for growing a layer of self-bonded silicon-carbide crystallites on the surface of a flexible carbon foil with subsequent impregnation of the formed structures by silicon melt is developed. Thermistors for a temperature range of 900–1450 K with s thermal sensitivity attaining 11 350 K able to be used in air are fabricated based on this composite material. The structural and electrophysical characteristics of the mentioned material are investigated.

The stimulated emission of Cu(In,Ga)Se2 alloy thin films formed by magnetron-assisted sputtering onto a sodium-fluoride layer deposited onto a molybdenum layer on a glass substrate is observed. The structural and optical parameters of the films are determined by scanning electron microscopy, local X-ray spectral microanalysis, X-ray structural analysis, and low-temperature luminescence (T = 10 K) measurements in the range of excitation levels of 1.6–75 kW cm–2 provided by nanosecond nitrogen-laser pulses. The stimulated emission threshold corresponds to ~25 kW cm–2. Comparative analysis of the emission of Cu(In,Ga)Se2 thin films suggests that the introduction of sodium results in significant improvement of the structural quality, specifically, in a decrease in the density of energy states in the band tails and in a decrease in the concentration of nonradiative-recombination centers.

The transverse and longitudinal photoconductivity, photoluminescence, and cathodoluminescence of sublimated (CdS)0.9–(PbS)0.1 films at room temperature and upon cooling are studied. The role of inclusions of the narrow-gap phase in the processes is shown. The films are excited over the entire active surface and pointwise (within one crystallite). The surface recombination rate and the lifetime of majority charge carriers at different generation rates and characters of excitation are estimated. A comparative table of recombination parameters of CdS and CdS–PbS films is presented.

Experimental results of a study concerned with solid-phase reactions and phase transformations in a Bi/Se nanoscale film structure under heat treatment in vacuum are presented. Nanocrystalline Bi2Se3, BiSe, and Bi4Se3 films are obtained for the first time by solid-phase synthesis at various ratios between the Bi and Se layer thicknesses. The phase-transformation temperatures at which Se, BiSe, and Bi4Se3 crystalline phases are formed are determined. The average crystallite sizes in the Bi2Se3, BiSe, and Bi4Se3 films are found to be 21, 23, and 33 nm, respectively.

The results of studying the surface Si layer and precipitate formation in CZ n-Si(100) samples sequentially implanted with 64Zn+ ions with a dose of 5 × 1016 cm2 and energy of 100 keV and 16O+ ions with the same dose but an energy of 33 keV at room temperature so that their projection paths Rp = 70 nm would coincide are presented. The post-implantation samples are annealed for 1 h in an inert Ar medium in the temperature range of 400–900°C with a step of 100°C. The profiles of the implanted impurities are studied by time-of-flight secondary ion mass spectrometry. The Si surface is visualized using a scanning electron microscope, while the near-surface layer is visualized with the help of maps of elements formed by Auger electron spectroscopy with profiling over depth. The ZnO(002) texture is formed in an amorphized Si layer after the implantation of Zn and O ions. ZnO(102) crystallites of 5 nm in size are found in a recrystallized single-crystalline Si layer after annealing in Ar at 700°C.

The structural, electrical, and optical properties of thin graphite-like films produced by magnetron- assisted sputtering onto crystalline silicon and quartz at substrate temperatures in the range from 320 to 620°C are studied. From analysis of the Raman spectra, it is established that, as the substrate temperature is elevated, the crystallite size increases and the concentration of structural defects and the content of amorphous carbon in the phase composition of the films decrease. It is found that, as the substrate temperature is elevated, the maximum of the absorption intensity in the ultraviolet spectral region of the optical absorption spectra shifts to longer wavelengths and the absorption intensity in the visible and near-infrared spectral regions increases. As the deposition temperature is elevated, the conductivity of the films increases from 0.2 Ω–1 cm–1 at 320°C to 30 Ω–1 cm–1 at 620°C.

Copper (I) oxide and zinc oxide films are formed on silicon and glassy quartz substrates by magnetron assisted sputtering. The thickness of the films is tens and hundreds of nanometers. The films are grown at different substrate temperatures and different oxygen pressures in the working chamber. The film samples are studied by the X-ray diffraction technique, scanning electron microscopy, and optical methods. It is established that an increase in the substrate temperature yields a change in the surface morphology of copper (I) oxide films towards the formation of well-pronounced crystallites. The reflectance and Raman spectra suggest that the quality of such films is close to that of bulk Cu2O crystals produced by the oxidation of copper. As concerns ZnO films, an increase in the substrate temperature and an increase in the partial oxygen pressure make it possible to produce films, for which a sharp exciton structure is observed in the reflectance spectra and the emission of excitons bound at donors is observed in the luminescence spectra.

In the work we investigate synthesis of aluminum nitride films using reactive ion plasma deposition in oxygen/nitrogen gas mixture for application as optical elements for power semiconductor lasers. The experimental refractive index of synthesized AlNO films is dependent on oxygen composition and is decreasing in diapason from 1.76 to 2.035 at elevation of the oxygen fraction.It is shown that the AlN films synthesized by pure nitrogen plasma are polycrystalline and textured. The oxygen presence in discharging gas results to growth of amorphous phase of the AlNO film.

Photosensitive elements based on polycrystalline lead sulfide layers are investigated. The influence of heterogeneous reactions at the crystallite–environment interfaces on the photosensitive-element characteristics is considered. It is shown that heat treatment in vacuum can be used to significantly change the parameters of the as-fabricated structures and optimize them for specific optoelectronic systems. A model is proposed to explain the nature of the observed phenomena.

The dependences of the electrical resistance on temperature (2–400 K) and magnetic field (0–140 kOe) of high-purity polycrystalline ytterbium were studied. Large magnetoresistance in the temperature range below 150 K (in low temperature hcp phase) was observed.

The physical and chemical properties of materials are greatly influenced by the state of their surface layers. In turn, the characteristics of the surface depend, for example, on the processes of absorption from a gas medium. In this study, by in situ measurements, the surface layers of polycrystalline silver exposed to external activated oxygen from different sources are investigated. For sources of activated oxygen, water vapor at a temperature of 1073 K and an ion source that makes it possible to obtain an oxygen ion beam with the energy 100–300 eV (5 μA/cm2) are used. It is established that, after treatment, the composition of AgO and Ag2O in the surface layers of silver includes, apart from atomic oxygen, molecular oxygen and silver in the zero-valence state. From estimates of the ratio between the intensities of spectroscopy peaks related to silver and oxygen components, it can be concluded that there exist associative forms of oxygen in the surface layers of silver. An increase in Ag 3d5/2–Ag 3d3/2 spin–orbit splitting is detected, which suggests that there are oxidized silver nanoparticles on the surface.

The basic features of the band structure observed in bulk samples are retained in polycrystalline SmS thin films. Specifically, the bottom of the conduction band is formed from s-type states and there exist donor impurity levels in the band gap, at an energy of 0.04–0.065 eV below the bottom of the conduction band.

The field and temperature dependences of the electrical conductivity of europium sulfide are studied in the temperature range 160–430 K. It is found that the electrical conductivity increases in strong electric fields of up to 2 × 104 V/cm by the Poole–Frenkel mechanism.

Experimental results of the formation of a periodic submicron structure on the surface of polycrystalline nickel (Ni) under laser irradiation in air and in a liquid medium (distilled water) are presented. The geometry of the formed surface structures is determined by electron-microscopy methods. When irradiated in air, the structure is formed above the base surface of the sample, and when irradiated in the liquid, it is formed below the base surface. The dimensions of the pure Ni nanoparticles formed during laser ablation of the nickel sample in the liquid were determined.

The interaction of magnetron-sputtered metal iron with titanium-oxide films upon isothermal vacuum annealing is studied by X-ray phase analysis, secondary-ion mass spectrometry, atomic-force microscopy, and mathematical simulation. A mechanism for the formation of complex oxides at grain boundaries is suggested. The mechanism is based on the reaction diffusion of metal iron into titanium oxide. A quantitative model of reaction interdiffusion in two-layer polycrystalline metal–oxide film systems with limited component solubility is developed. From numerical analysis of the experimental distributions of the metal concentrations in the Fe–TiO2 film system, the individual diffusion coefficients are determined. It is found that, under the conditions of vacuum annealing at 1073 K, the diffusion coefficients of iron and titanium are 8.0 × 10–13 and 3.0 × 10–15 cm2 s–1, respectively.

The effect of the condensation temperature on the growth rate, structure, and optical properties of zinc-selenide films produced by radio-frequency magnetron sputtering is studied. As the deposition temperature is increased, the film thickness decreases. Polycrystalline zinc-selenide films consist of a mixture of cubic and hexagonal phases, of which the cubic phase is dominant. A correlation between the refractive index and the crystallite size is shown.

Galvanomagnetic effects in twisting bicrystals of Bi1–x Sb x alloys (0.07 ≤ x ≤ 0.2) at low temperatures and in magnetic fields up to 40 T are studied. It is found that, at small crystallite misorientation angles, the semiconductor–semimetal transition is induced in the central layer (~60-nm-thick) and two adjacent layers (each ~20-nm-thick) of the interface at different values of ultraquantum magnetic field. Bicrystals with large misorientation angles, being located in strong magnetic fields, exhibit quantum oscillations of the magnetoresistance and the Hall effect, thus indicating that the density of states is higher and charge carriers are heavier in the adjacent layers of the interfaces than in the crystallites. Our results show also that twisting bicrystals contain regions with different densities of quantum electronic states, which are determined by the crystallite misorientation angle and magnetic-field strength.

Polycrystalline and single-phase ZnO:Al:Er3+ films are synthesized by the sol–gel method (based on different types of solvents) on surfaces of single-crystal silicon and glass. The electrical measurement data (current–voltage and capacitance–voltage characteristics) show that these ZnO:Al:Er3+ films are photosensitive. The introduction of Er3+ rare-earth ions into a zinc-oxide film manifests itself in photosensitivity of the current–voltage and capacitance–voltage characteristics to light in the visible and infrared (IR) spectral ranges. The results of this study indicate that ZnO:Al:Er3+ films synthesized by the sol–gel method can be used to design optoelectronic devices, in particular, to form solar-cell active layers.

It has been found that “hot” high-fluence Zn+ implantation leads to the formation of the extended layer with zinc-based nanoclusters of size up to 10 nm in SiO2 film. The precipitate’s crystalline nature is confirmed by HRTEM studies. Post-implantation annealing at 700°C for 60 min leads to Zn atoms redistribution in implanted region, formation of the larger crystallites (up to 25 nm) and the small Zn nanoparticles surrounded by the oxide shells (core (Zn)/shell(ZnO) structure) as well as the voids formation at the interface “Zn nanocluster/SiO2 matrix”. The number of the core (Zn)/shell (ZnO) structures and the voids increases after annealing at 700°C for 120 min.

The characteristics of the optical absorption of copper-activated zinc-sulfide polycrystalline layers after preliminary heat treatment are investigated. The composition of the compound under study was monitored by X-ray fluorescence analysis. The band gap Eg and characteristic Urbach energy are estimated from the fundamental absorption edge. The contribution of structural defects and the impurity factor to the variation in the optical properties is discussed.

The electrical parameters of polycrystalline Sm1–xEuxS compounds are studied. The conductivity, concentration of free electrons, their mobility, and the conductivity activation energy are measured as functions of the quantity x. The structural parameters of the compounds are determined. A heterostructure is fabricated with x in the range from 0 to 0.3, and the electrical voltage generated by the structure, when heated to a temperature of T = 450 K, due to the thermovoltaic effect is measured. This voltage is found to be 55 mV. A method for measuring the thermally induced voltage is described. The method provides a means for separating the thermovoltaic effect from the Seebeck effect.

The effect of annealing in argon and oxygen plasma on the I–V characteristics and photoresponse of TiO2–Si structures is investigated. The titanium oxide films are prepared by rf magnetron sputtering onto n-Si substrates. The observed features in the behavior of the electrical and photoelectric characteristics of the samples after annealing and treatment in oxygen plasma are attributed to a variation in the phase composition of the oxide film due to the appearance of anatase or rutile crystallites, depending on the treatment conditions.

The systematic features of the formation of the low-resistivity compound Cu3Ge by low-temperature treatment of a Cu/Ge two-layer system in an atomic hydrogen flux are studied. The Cu/Ge two-layer system is deposited onto an i-GaAs substrate. Treatment of the Cu/Ge/i-GaAs system, in which the layer thicknesses are, correspondingly, 122 and 78 nm, in atomic hydrogen with a flux density of 1015 at cm2 s–1 for 2.5–10 min at room temperature induces the interdiffusion of Cu and Ge, with the formation of a polycrystalline film containing the stoichiometric Cu3Ge phase. The film consists of vertically oriented grains 100–150 nm in size and exhibits a minimum resistivity of 4.5 µΩ cm. Variations in the time of treatment of the Cu/Ge/i-GaAs samples in atomic hydrogen affect the Cu and Ge depth distribution, the phase composition of the films, and their resistivity. Experimental observation of the synthesis of the Cu3Ge compound at room temperature suggests that treatment in atomic hydrogen has a stimulating effect on both the diffusion of Cu and Ge and the chemical reaction of Cu3Ge-compound formation. These processes can be activated by the energy released upon the recombination of hydrogen atoms adsorbed at the surface of the Cu/Ge/i-GaAs sample.

The band of intrinsic (e–h) radiation emission by the subsurface potential barriers of crystal grains and the edge doublet band arising as LO-phonon replicas of the e–h band are observed in the spectra of the low-temperature (4.2 K) photoluminescence of fine-grained (with a grain size of dcr ≤ 1 µm) CdTe films. Film doping with the In impurity results in quenching of the doublet band, while heat treatment leads to activation of the intrinsic band, a short-wavelength shift of the red boundary (ΔEr = 16–29 meV) and the halfwidth modulation (ΔA = 6–17 meV) of which correlate with the height of micropotential barriers and the temperature of recombining hot photocarriers.

The structure of graphene layers grown by sublimation on a 6H-SiC (000\(\bar 1\)) substrate surface is studied by electron diffraction depending on the sublimation temperature and substrate-surface pretreatment method. It is shown that the use of polishing sublimation etching of the substrate before thermal destruction at a temperature of 1350°C on the substrate surface results in the formation of single-crystal graphene domains with graphene-lattice rotation by 30° with respect to the SiC lattice and a small fraction of amorphous domains. An increase in the temperature to 1500°C leads to the partial formation of a polycrystalline graphene phase with turbostratic structure while retaining the preferred orientation of graphene crystallites as at 1350°C. The use of pregrowth annealing before thermal destruction makes it possible to grow a graphene film with a more ordered and homogeneous structure without inclusions of amorphous and polycrystalline components. The preferred orientation of graphene domains in the film remains unchanged.

The results of using carbidsiliconoxide (a-C:SiO1.5) films with a thickness of 30–60 nm, produced by the pyrolysis annealing of oligomethylsilseskvioksana (CH3–SiO1.5)n with cyclolinear (staircased) molecular structure, as intermediate films in the hydride vapor phase epitaxy of gallium nitride on polycrystalline CVD-diamond substrates are presented. In the pyrolysis annealing of (CH3–SiO1.5)n films in an atmosphere of nitrogen at a temperature of 1060°C, methyl radicals are carbonized to yield carbon atoms chemically bound to silicon. In turn, these atoms form a SiC monolayer on the surface of a-C:SiO1.5 films via covalent bonding with silicon. It is shown that GaN islands grow on such an intermediate layer on CVD-polydiamond substrates in the process of hydride vapor phase epitaxy in a vertical reactor from the GaCl–NH3–N2 gas mixture.

The influence of the Gd content on the semiconductor–metal phase transition in polycrystalline Sm1–xGd x S thin films produced by the flash evaporation of a powder in vacuum is studied. It is shown that the basic factor of the physical mechanism of the phase transition is compression of the film material. It is established that the films retain their semiconductor properties only up to a Gd content of x = 0.12.

Flash evaporation is used to grow Bi0.5Sb1.5Te3 films 1200 nm thick on mica substrates. The average lateral crystallite sizes in the as-grown films are ~800 nm. The (0001) plane in the crystallites is preferentially parallel to the substrate plane. After heat treatment in an argon atmosphere, the effective lateral size of crystallites in which the third-order axis is perpendicular to the substrate plane increased by a factor of 3–5. The crystallites were preferentially oriented in the substrate plane as well. The thermoelectric-power parameter of Bi0.5Sb1.5Te3 films after their heat treatment in an inert environment increased approximately twofold to values close to that of the corresponding single crystals.

Polycrystalline alloys Fe2TiSn1–x Si x (0 ≤ x ≤ 1) theoretically predicted as highly efficient thermoelectric materials are experimentally studied. Structural studies show that the partial substitution of Sn with Si results in the formation of a multiphase state in samples with x > 0. Impurity phases in general lead to a significant decrease in the Seebeck coefficient and an increase in the thermal conductivity of Fe2TiSn1–x Si x samples, which does not allow consideration of these materials as promising thermoelectrics.

The results of studying the surface of 15- to 100-nm-thick bismuth films by atomic-force microscopy are reported. The near-linear character of the dependences of the average surface roughness and the average height of growth patterns on the film thickness is established. It is found that the average crystallite size increases, as the film thickness is increased. A slight dependence of the crystallite size on the film thickness is observed at thicknesses in the range of 27–70 nm.

Thin polycrystalline Sm1–x Eu x S films (x = 0.1, 0.167, 0.2, 0.25, 0.33, 0.5) were prepared by evaporation of SmS and EuS powders. Structural features of the films were investigated. The influence of Eu concentration and temperature of film deposition on the value of lattice parameter and sizes of X-гау coherent scattering regions was studied. It is shown that formation of Sm1–x Eu x S films comes about according to the theory that was previously suggested for SmS films and that the deviation of lattice parameter is explained by the variable valence of samarium ions.