The processes of correcting the optical characteristics of multilayer interference filters and heterojunctions obtained by liquid epitaxy on the base of In4Se3, In4(Se3)1-x(Te3)x and CdSb crystals were studied by laser modification of the film structure. The conditions for optimization of the properties of the created elements for use in the infrared range by laser action are determined.

The graphical-analytical method was used to find the solution of the inverse problem in ellipsometry for the system consisting of a transparent single-layer dielectric film on the Cd1-xMnxTe crystal substrate. The nomograms in the φ-Δ ellipsometric coordinates were simulated to determine the refractive index of the film and its thickness for different incidence angles of the laser beam with 632.8 nm wavelength. The treatment of the Cd1-xMnxTe (х=0.1-0.4) thin films and crystal surfaces was carried out with the millisecond (τ=1.5 ms) and nanosecond (τ=80 ns) laser. The structuralphase transformations of the films and layers in the Cd-Mn-Te system were studied in the AFM and SEM, and their ellipsometric characteristics were determined using photometric laser ellipsometer. The heterogeneity of the thickness and structure of the laser-modified Cd1-xMnxTe surface layers were analyzed using calculated distribution of the refractive index of the films and its dependence on the incidence angle of the laser beam.

The modified surface layers of the Cd1-xMnxTe crystals were obtained by the laser recrystallization of the crystal surface with the use of millisecond and nanosecond ruby ​​lasers. The determination and diagnostics of the layer structural state were performed by the study the electron channeling patterns in the SEM. The AFM studies showed that mechanically stable contact regions in the CdTe crystal – Cu film system can be formed, depending on the laser energy density and beam defocusing. On the base of the ellipsometric studies, it was found that while irradiating the Cd1-xMnxTe crystal surface, the refractive index of the oxide film on the modified surface changes depending on the laser beam energy density, which can be interpreted as the formation of the oxides of the different chemical composition.

Peculiarities of morphology and electric properties of X-ray and gamma-ray detectors developed by graphene deposition onto commercially available (111) oriented CdTe:Cl wafers has been investigated. Laser treatment of graphene contact using millisecond YAG-laser with an energy density of 0.1-4.5 J/cm(2) has been carried out in order to modify and improve their structure and phase state.

In this paper, the transformations of the morphology and surface structure of CdTe crystals under the action of pulsed laser radiation and the properties of laser-optimized Schottky diode X/γ-ray detectors developed by Ni and NiO deposition onto commercially available (111) oriented CdTe:Cl wafers has been investigated. Using scanning electron and atomic force microscopy, it was shown that, depending on the energy density and laser pulse duration, the morphology, phase composition and distribution of the system of defects and inclusions in the surface areas of CdTe crystals can be optimized. The analysis of the effect of laser treatment on the electrical and spectrometric properties CdTe X/γ-ray detectors under study was also carried out.

Epitaxial layers and complex heterostructures on the base of the CdTe and Cd1-xMnxTe crystals were obtained by pulsed laser irradiation both in their transparency and absorption regions. Structural perfection of the laser-epitaxial layers, transition regions and distribution of the Te and Cd inclusions in the area of the laser action were studied. Analysis of the U-V and C-V characteristics of the obtained structures indicates a decrease in influence of surface states at the hetero-boundaries as a result of laser treatment in optimal mode, and also a reduction of reverse dark current and loss current. The spectral characteristics of the laser-epitaxial structures on the base of CdTe and Cd1-xMnxTe show, that they are promising materials for X- and gamma-radiation detectors.

The transformations of the morphology and surface structure of Cd1-xMnxTe crystals under the action of pulsed laser radiation and the properties of laser-optimized barrier structures on these crystals obtained by high-frequency cathode sputtering were studied. Using scanning electron (SEM) and atomic force (AFM) microscopy, it was shown that, depending on the energy density and laser pulse duration, the morphology, phase composition and distribution of the system of defects and inclusions in the surface areas of Cd1-xMnxTe crystals can be optimized. A theoretical prediction of the surface temperature and the melting threshold of Cd1-xMnxTe crystals for various laser treatment modes was made. It was shown that the quality of the laser treated surface of Cd1-xMnxTe crystals (x=0.1-0.45) can be estimated from the maximum contrast of the lines in the electron channeling patterns in SEM. Active heterostructures were obtained using the RF cathode sputtering of thin CdSb, ZnSb films on Cd1-xMnxTe crystals. The transformation of the polycrystalline granular structure of these films in the field of the laser action was studied using scanning images in AFM. It was found that grains coalescence processes contribute to the optimization of both the adhesion and structure of the films, as well as the electrophysical characteristics of the barrier structures.

The transformations of the morphology and surface structure of Cd 1-x Mn x Te crystals under the action of pulsed laser radiation and the properties of laser-optimized barrier structures on these crystals obtained by high-frequency cathode sputtering were studied. Using scanning electron (SEM) and atomic force (AFM) microscopy, it was shown that, depending on the energy density and laser pulse duration, the morphology, phase composition and distribution of the system of defects and inclusions in the surface areas of Cd 1-x Mn x Te crystals can be optimized. A theoretical prediction of the surface temperature and the melting threshold of Cd 1-x Mn x Te crystals for various laser treatment modes was made. It was shown that the quality of the laser treated surface Cd 1-x Mn x Te crystals (x=0.1-0.45) can be estimated from the maximum contrast of the lines in the electron channeling patterns in SEM. Active heterostructures were obtained using the RF cathode sputtering of thin CdSb, ZnSb films Cd 1-x Mn x Te crystals. The transformation of the polycrystalline granular structure of these films in the field of the laser action was studied using scanning images in AFM. It was found that grains coalescence processes contribute to the optimization of both the adhesion and structure of the films, as well as the electrophysical characteristics of the barrier structures.

Peculiarities of heteroepitaxial growth of CdSb thin films on A(II)B(VI) and A(III)B(VI) single crystal substrates were studied by atomic-force and scanning electron microscopy. New thin film CdSb-Cd1-xMnxTe and CdSb-In-4(Ses)(1-x)Te-3x heterojunctions were obtained by high-frequency cathode sputtering of CdSb single crystal target. Laser treatment of CdSb films using millisecond YAG-laser with energy density of 0.1-4.5 j/cm(2) has been carried out in order to modify and improve their structure and phase state. Stoichiometry of composition and granular polycrystalline structure of CdSb films on Cd1-xMnxTe and In-4(Se-3)(1-x)Te-3x. substrates have been confirmed by SEM and AFM studies. A stepwise growth processes of grains were detected under laser treatment in CdSb films. Anisotropic shape of grains in CdSb films was found depending on crystallographic orientation of In4Se3 substrate surface. (C) 2016 Elsevier B.V. All rights reserved.

CdSb thin films have been deposited on single crystals of layered III–VI compounds In4Se3 and In4Te3 by ion–plasma RF sputtering to obtain new heterojunctions of two compounds with significant mismatch of lattice constants. Conditions of heteroepitaxy of CdSb films strongly differ at deposition on the surface of In4Se3 or In4Тe3 crystals. CdSb films on In4Se3 substrates with crystallite size of 400–600nm have been obtained at optimal RF power mode, that is confirmed by SEM and AFM microscopy studies. The results of electron probe microanalysis confirm compliance of films' composition with stoichiometric CdSb. For CdSb films deposited on In4Тe3 crystal substrates a system of islands due to Stranski–Krastanov mechanism was recorded. Morphologically different forms of CdSb film growth are promising for the creation of active regions of elements for various applications. Photosensitive elements for near-infrared region with the given selective position of the photosensitivity maxima have been studied on the base of the obtained CdSb–In4Se3 and CdSb–In4Тe3 film heterojunctions.

The presence in food and the environment of nitrates, organic and other substances harmful to humans can be identified by their characteristic molecular spectra in the near infrared radiation. When developing optical sensors, whose work is based on the determination of the spectral absorption characteristics of organic matter, it is necessary to apply cutting optical filters for the selection of certain infrared ranges of the spectrum. The work carried out to develop multilayer thin film interference filters with replaceable cutting position limits infrared radiation depending on the concentration and type of the studied compounds. The peculiarity of these filters is the use of semiconductor crystals In 4 Se 3 , In 4 Te 3 and CdSb as substrates for thin-film multilayer coating. High stability of the spectral characteristics, resistance to chemicals and atmospheric action of single crystals In 4 Se 3 , In 4 Te 3 and CdSb enables the design based on these filters with λ =1.7-6.5 um different positions of shortwave radiation limits cutting range and a maximum transmittance T max =91-95%. The method of SEM studies depending on the structure of thin films -component filters ZnS, SiO, Ge, Te, SrF 2 on technological factors and on spectral and mechanical stability of the multilayer coating are used. The requirements to design solutions of the active cell optical biosensor developed with the use of infrared filters. The method and simulation modeling to build adaptive reconfigurable computer information-measuring system of rapid analysis of qualitative composition and quantitative parameters of molecular spectra of bioactive substances are proposed.

Photosensitive elements of semiconductor compounds In 4 Se 3 , In 4 Te 3 , CdSb and heterostructures were obtained by liquid phase epitaxy method. Laser modification of structural and phase state of epitaxial layers was conducted. The methods of SEM, AFM and STM microscopy were used for investigation of transformation processes in nanostructured regions on boundaries of hetero structures. Spectral characteristics and parameters of photosensitive elements and IR filters were studied. Interference absorptive filters for cutting off infrared range of the spectrum were formed by deposition in a vacuum on these crystals of thin films.

Photosensitive elements on the basis of CdSb and Cd1-xZnxSb single crystals, doped with Te, In, Ga, are obtained by liquid-phase epitaxy. CdSb and Cd1-xZnxSb epitaxial layers are exposed to pulsed laser radiation with energy density 2-10 J/сm2. CdSb layers surface acquires a more ordered planar morphology, density of structural defects in the heterojunction and width of the transition region are reduced at optimal mode of laser processing speed. Laser beam stimulates transformation of metastable cadmium antimonide phase inclusions into CdSb equilibrium phase. Photosensitivity of Cd1-xZnxSb based heterojunction cells is increased. The optimal level of photosensitivity is achieved by doping basic single crystals by Te. Interference bandpass filters in the form of SіO, Ge, BaF2, ZnS thin films on ZnSb single crystal are designed. Selection of incident IR radiation on the photosensitive element by such filter makes it possible to block solar and other noises in the wavelength range λ<2 micron.

Методом рідиннофазової епітаксії отримані фоточутливі елементи на основі базових монокристалів CdSb і Cd1-xZnxSb, легованих домішками Te, In, Ga. Після оптимальних режимів обробки лазером східчаста поверхня шарів CdSb набуває впродядковану планарну морфологію, зменшується густина структурних дефектів в області гетерограниці та ширина перехідної області. Оптимальна фоточутливість епітаксійних структур досягається легуванням підкладок домішкою Те.