CdS–PbS nanocrystalline films with a thickness of 0.5 to 1.2 µm are obtained by Chemical Bath Deposition (CBD) from an ammonium-citrate reaction mixture by varying the concentrations of different cadmium salts CdAn n ( An is CH 3 COO − , NO_3^ - , SO_4^2 - ) within 0.01–0.08 mol/L. The morphology and surface topography of the films are studied by scanning electron and atomic-force microscopy. The film’s composition is determined by energy-dispersive analysis. A nonlinear change in the content of the main CdS–PbS film elements and their morphological characteristics is shown. The influence of the anionic component of the salt CdAn n on the cadmium content in thin film layers is established. This effect correlates with the lyotropic series of anions: SO_4^2 - > NO_3^ - > CH 3 COO − . A mechanism for the anion nucleophilic addition to the thiocarbonyl atom of thiourea is proposed. As a result, a nucleophilic attack promotes thiourea activation by weakening the carbon–sulfur bond. Based on the results of comprehensive study of the morphology and the fractal analysis of the surface of the CdS–PbS semiconductor layers, we conclude that the studied films are predominantly formed by particle–cluster diffusion-limited aggregation (DLA).

The results of studies of the morphology and photoelectric characteristics of nanostructured thin-film photoresistors based on Cd x Pb 1 – x S obtained by modifying their composition are analyzed. The surface morphology of photosensitive elements is analyzed by scanning electron microscopy and high-resolution transmission electron microscopy. Auger-electron microscopy is used to determine the elemental composition of thin the films and the distribution of elements according to thickness. Photoresistors are prepared by physical sputtering and chemical-bath deposition from aqueous solutions with various additives. To increase the sensitivity, oxygen is introduced into films of the composition Cd 0 Pb 1 S: into physically sputtered layers by high-temperature annealing and into chemically deposited layers by the addition of oxidants. To obtain Cd x Pb 1 – x S layers, hydrochemical deposition from an ammonium-citrate reaction mixture is used with varying concentrations of cadmium sulfate in the range of 0.01–0.1 mol/L.

Intense CdS luminescence in the blue and green spectral regions is widely used in all areas of optoelectronics. In this spectrum band are working on lasers CdS. This paper presents the results of a study of the exciton region of the CdS spectrum based on the theory of anti-intersecting bands (bands anticrossing theory-BAC) with the involvement of broader initial data for the analysis of optical properties. Depending on the growth conditions, the presence and change of oxygen concentration and intrinsic point defects determining the composition of crystals are taken into account. The concept of the nonuniform distribution of isoelectronic oxygen centers in the bulk of CdS due to their predominant segregation on compensating stacking faults is introduced. Cathodoluminescence (CL) spectra were studied using various recording methods, excitation intensity and temperature, as well as pulsed CL at high excitation intensities. In a scanning electron microscope from local registration and a high excitation density, the emission of the edge luminescence components of CdS was detected at 300 K. To analyze the optical data, we used the capabilities of the method for constructing band models based on the BAC theory, which collects extensive and multilateral information about specific samples. A model of a CdS · O multizone with stacking faults, which determines the spectrum of edge emission is presented. An explanation of the nature of the green edge emission of cadmium sulfide as excitons localized on oxygen-containing complexes in SF layers has been obtained for the first time. It was found that the system of levels of localized excitons at stacking faults does not change either with temperature up to 300 K, or with a change in the oxygen solubility in the crystal to the limiting one. It is shown that the presence of isoelectronic oxygen centers appear itself in the electro-physical properties of crystals. Recommendations are given for the diagnostics of crystals suitable for the creation of luminescent systems or lasers that are stable in operation. Keywords: isoelectronic centers, bands anticrossing theory, localized exciton, stacking faults, point defects, stimulated radiation.

Films obtained by chemical deposition of thiourea onto a quartz substrate from the citrate-ammonia reaction mixture containing 0.01, 0.04 and 0.1 mol/l cadmium nitrate at constant concentration of lead salt is obtained. The formation of single- and two-phase films depending on the cadmium nitrate content in the reactor is established by X-ray diffraction, scanning electron microscopy and auger spectroscopy.

Herein, we describe the nonlinear processes for the formation of thin films of the PbS-CdS system using chemical bath deposition with a gradual change in the cadmium nitrate content in the reaction mixture. The morphology of films was studied via scanning electron microscopy and atomic force microscopy. The mechanism for the formation of thin-film compounds can be considered as cluster-particle aggregation (diffusion-limited aggregation). X-ray diffraction confirmed the formation of single-phase layers of substitutional B1-type CdxPb1-xS solid solutions (space group Fm3[combining macron]m) when the concentration of cadmium nitrate in the reaction bath increased up to [Cd(NO3)2] = 0.08 M. The maximum cadmium content in CdxPb1-xS solid solutions was determined to be x = 0.094. At the concentration of [Cd(NO3)2] = 0.10 M, a two-phase film was formed, where the film consisted of crystallites of cubic CdxPb1-xS with x = 0.071 (lower compared to the film obtained at [Cd(NO3)2] = 0.08 M) and fine-crystalline hexagonal B4-type Cd1-δS (space group P63mc). The texture of grains forming films was observed; where a predominant orientation with the (111) plane along substrate in PbS changed to the (200) plane in CdxPb1-xS films, the portion of (200) oriented grains increased with an increase in cadmium nitrate content up to [Cd(NO3)2] = 0.08 M, and at 0.10 M of cadmium nitrate, a radical change in the type of texture to the (111) type occurred. The concentration [Cd(NO3)2] = 0.10 M is called the critical concentration, where under this condition, the deposition process occurs due to the excess Gibbs energy. The higher cadmium content x in films determined by the energy-dispersive X-ray analysis and Auger spectroscopy compared with that estimated from the crystal lattice parameter is associated with the presence of an additional amorphous CdS phase formed as a sublayer distributed in intercrystalline spaces and island formations. Optical studies showed a nonlinear change in the band gap (Eg) of obtained films from 0.53 to 0.76 eV, whereas at the critical cadmium salt concentration (0.10 M), two crystalline phases with Eg equal to 0.73 and 2.47 eV were observed.

Films of cubic substitutional CdxPb1-xS solid solutions have been synthesized by the chemical bath deposition with varying cadmium acetate salt Cd(CH3COO)(2) in the reaction mixture within 0.01-0.08 mol/1 on quartz substrates. The crystal structure, chemical composition and morphology were studied by the X-ray diffraction, scanning electron microscopy, elemental analysis, Auger spectroscopy, and Raman spectroscopy, as well as the evolution of the optical and photoelectric properties was determined. The thickness of the deposited films changes from similar to 0.4 to similar to 1.0 mu m, and the content of cadmium x in the CdxPb1-xS solid solution varies from 0.036 to 0.090. All the CdxPb1-xS films have B1 crystal structure (NaCl type), but differ in the morphology (the size, form and predominant orientation of the particles forming the films). Forming the substitution solid solution is confirmed by the shift of the Raman lines at 72 and 134 cm(-1) toward higher frequencies. The optical band gap determined from the absorption spectra varies from 0.46 to 0.70 eV. The dependences of the photoresponse value (volt-watt sensitivity) and the dark resistance on cadmium acetate concentration in the solution are represented.

The possibility of forming thin-film two-phase compositions Cd x Pb 1- x S/Cd 1− δ S using chemical bath deposition from aqueous media with adding various cadmium salts has been demonstrated. The crystal structure, chemical composition, morphology, and the band gap were studied by the X-ray diffraction, scanning electron microscopy, elemental analysis, Auger and Raman spectroscopy, and diffuse reflectance measurements. The formation of a Cd x Pb 1− x S/Cd 1− δ S substitutional solid solution phase in well-faceted crystallites on the substrate of an X-ray amorphous CdS phase was experimentally shown. The observed difference in the composition of the films deposited with adding different cadmium salts is the result of the effect of the nucleophilicity of the anionic component of these salts on the kinetics of thiourea decomposition. The results demonstrate the possibility of forming thin-film two-phase compositions or heterostructures on the base of cadmium and lead sulfides in one technological stage using chemical bath deposition, which can be important for the creation of solar cells.

Intense CdS luminescence in the blue and green spectral regions is widely used in all areas of optoelectronics. In this spectrum band are working on lasers CdS. This paper presents the results of a study of the exciton region of the CdS spectrum based on the theory of anti-intersecting bands (bands anticrossing theory - BAC) with the involvement of broader initial data for the analysis of optical properties. Depending on the growth conditions of CdS, the presence and change in the oxygen concentration, as well as the equilibrium of intrinsic point defects, which determines the change in the composition of the crystals. The concept of the nonuniform distribution of isoelectronic centers in the bulk of CdS due to their predominant segregation on compensating stacking faults is introduced. Cathodoluminescence (CL) spectra were studied using various recording methods, excitation intensity and temperature, as well as pulsed CL at high excitation intensities. In a scanning electron microscope from local registration and a high excitation density, the emission of the edge luminescence components of CdS was detected at 300 K To analyze the optical data, we used the capabilities of the method for constructing band models based on the BAC theory, which. collects extensive and multilateral information about specific samples. A model of a CdS O multizone with stacking faults is presented, which determines the spectrum of edge emission. An explanation of the nature of the green edge emission of cadmium sulfide as excitons localized on oxygen-containing complexes in SF layers has been obtained for the first time. It was found that the system of levels of localized excitons at stacking faults does not change either with temperature up to 300 K, or with a change in the oxygen solubility in the crystal to the limiting one. It is shown that the presence of isoelectronic oxygen centers appear itself in the electro-physical properties of crystals. Recommendations are given for the diagnostics of crystals suitable for the creation of luminescent systems or lasers that are stable in operation.

CdxPb1-xS films with a thickness of 620 and 680 nm were prepared by chemical precipitation from a reaction mixture containing lead salt, thiourea, alkali and cadmium acetate. The concentration of cadmium acetate was 0.01 and 0.1 mol/l. Electron-microscopic studies showed a fundamental difference in the morphology of the CdxPb1-xS thin films with a 10-fold difference in the concentration of cadmium acetate in the reaction bath. The results of energy dispersive analysis indicate the nonstoichiometry of the synthesized films on sulfur. Auger spectrometry revealed a high content of oxygen in the surface layer of the thin film coating CdxPb1-xS (up to 10 and 40 at. %). In the sample obtained from the reaction bath containing 0.01 mol/l of cadmium acetate, after ion etching at a depth of more than 30 nm, no oxygen was detected. In a sample prepared with a cadmium acetate content of up to 0.1 mol/l, the oxygen content does not exceed 3 at. %

The specific features of the emission spectra of pure chemical-vapor deposited (CVD) ZnSe condensates grown with an excess of selenium and with doping with oxygen are studied. The anomalous 477(490)-nm edge emission prevailing in the low-temperature cathodoluminescence spectra of ZnSe(O) is studied in order to elucidate the nature of this emission. The relation of this emission to the stoichiometry composition of ZnSe and to the concentration of dissolved oxygen is established. The data suggesting the role of the copper impurity are obtained. On the basis of the band-anticrossing theory, a band model is developed to interpret the nature of the basic luminescence bands of ZnSe(O) and ZnSe(O,Cu) in the near-edge spectral region. It is shown that the model for ZnSe(O) is similar to the model previously proposed for ZnS(O) and CdS(O).

The features of the emission spectra of high-purity CVD ZnSe condensates grown with excess selenium and strong oxygen doping were studied. Investigated prevalent in the spectra of low-temperature cathodoluminescence of ZnSe∙O abnormal edge emission 477-490 nm to ascertain its nature. The connection of this luminescence with the stoichiometric composition of ZnSe and the concentration of dissolved oxygen is established.Obtained data indicating the role admixture of copper. Based on the theory of anti-crossing zones, a band model is presented, explaining the nature of the main luminescence bands of ZnSe∙O in the near edge region of the spectrum. It is shown that the model is identical for ZnSe, ZnS and CdS.

The results of the analysis of carbon-containing materials are presented based on an analysis of the peaks of X-ray photoelectron spectroscopy (XPS) formed by the electrons leaving the analyzed sample in a vacuum without energy loss (peak shape analysis, PSA) and based on the interpretation of the widest possible area of energy loss adjacent to the photoelectron spectroscopy (PES) peak. It is shown that the PES analysis of diamond-like materials containing alloying additives, the concentration of which is comparable with the concentration of carbon, is not effective. The PES analysis of graphene oxide samples that were heat-treated to remove oxygen gave detailed information about the laws of the energy loss of photoelectrons emitted from the 1 s level, which determines the allotropic variety of carbon.

The article establishes the upper temperature steadiness limit of СdxPb1-xS supersaturated solid solutions obtained by chemical bath deposition. СdxPb1-xS (x = 0.06; 0.122; 0.176) and (x = 0.02–0.05) films remained stable under the heating up to 405–410 and 450 K, respectively. SEM studies have shown that heating of СdxPb1-xS films (x = 0.02–0.05) to 620 K leads to the structure destruction. Internal mechanical compressive stresses at the "СdxPb1-xS film-substrate" interface was calculated in the range of 300–900 K for the first time ever, the highest values reached 2000–2750 kN/m2 for a number of the films compositions. In contrast to solid solutions, the expansion stresses up to 100 kN/m2 were derived for the CdS layer at 900 K. The obtained temperature steadiness boundaries and the mechanical stresses of СdxPb1-xS films must be taken into account in the development of photonic devices based on such materials.

— Using scanning electron microscopy and X-ray photoelectron spectroscopy, we investigate the chemical forms of tungsten incorporated into diamond-like silicon–carbon films. The films are fabricated by simultaneously carrying out the plasmochemical decomposition of a silicon organic precursor and magnetron sputtering of the metal. Films of tungsten-containing diamond-like silicon–carbon nanocomposites are found to contain a considerable amount of the amorphous phase of tungsten oxide, along with nanocrystalline tungsten carbide.

The structures of the lead sulphide and lead selenide based photoresistors are examined. The simulation allowed us to explain the experimentally observed differences in the photoconductivity relaxation time between two different types of photoresistors.

The cathodoluminescence and absorption of plastically deformed ZnS(O) single crystals are investigated in the light of band-anticrossing theory. The difference in the oxygen content in the surface layer and in the sample bulk is found using a scanning electron microscope and according to cathodoluminescence data. This fact explains the specifics of the spectral position of the fundamental absorption edge and exciton spectra. The shift dynamics of the bands of self-activated luminescence on deep A centers (SA luminescence) during deformation recrystallization with an increase in the dissolved oxygen concentration is presented. Restriction of the spectral range of the appearance of self-activated luminescence at shallow levels—“edge” luminescence—is established. The nature of the emission bands in the wavelength ranges of 336–350 and 364–390 nm is established. These results refine the energy model of ZnS(O) crystals and can be useful in the case of the practical use of their structure-sensitive properties.

The article describes the problems associated with previous Federal State Education Standards (FSES) in the Electronics and Nanoelectronics education speciality and education plans of the Light Engineering and Light Sources Bachelor’s programme as well as education plans of the Theoretical and Applied Light Engineering Master’s programme. Due to the adoption of FSES3++ and approval of professional educational standards, the light engineering community was offered to take part in the discussion of the issues of new education plans elaboration.

Abstract The optical properties of plastically deformed ZnS∙0 single crystals have been studied on the basis of bandanticrossing theory. The difference in oxygen concentration in the surface layer and in the bulk of the sample was found from an analysis of the results of cathodoluminescence and scanning electron microscopy. This made it possible to explain the position of the fundamental absorption edge and exciton spectra. Dynamics of the shift of the self-activated luminescence at deep A-centers bands during deformation recrystallization with increasing concentration of dissolved oxygen is shown. The restriction of the spectral range of the appearance of self-activated luminescence at shallow levels is established. The nature of the emission bands in the wavelength range 336-350and 364-390 nm has been discovered. The results can be used both to refine the energy model of ZnS∙O and in the case of practical use of the structure-sensitive properties of zinc sulphide crystals.