http://dspace.nbuv.gov.ua:80/handle/123456789/114617 Fri, 17 Apr 2026 23:16:18 GMT 2026-04-17T23:16:18Z http://dspace.nbuv.gov.ua:80/bitstream/id/341308/ http://dspace.nbuv.gov.ua:80/handle/123456789/114617 http://dspace.nbuv.gov.ua:80/handle/123456789/119244 Features of electrical charge transfer in porous silicon Monastyrskii, L.S. The thermostimulated depolarization (TSD) spectra of porous silicon (PS) in the range of temperatures 77 - 450 K were investigated. Several wide bands of TSD current with different values referred to different types of PS charged defects were discovered. Comparative investigation of TSD spectra of PS layers and films of dioxide silicon on the silicon substrates were carried out. There was fixed the identification of low-temperature (77 - 300 K) parts of these spectra. Activation energies of defects and capture centers of PS were calculated. Low-temperature defects were identified as hydrogen - oxygen type ions. Infrared- and x-rays influence of PS on TSD spectra were fixed. An energy scheme of charge transport in PS based on changes in TSD spectra were proposed. Temperature changes of planar current - voltage characteristics and frequency dispersion of the capacity of porous silicon - silicon substrate heterostructures were investigated. The anomalous character of dependencies is explained by special features of ion transfer in PS. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119244 2001-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119243 Structural investigations of annealed ZnS:Cu, Ga film phosphors Lytvyn, O.S.; Khomchenko, V.S.; Kryshtab, T.G.; Lytvyn, P.M.; Mazin, M.O.; Prokopenko, I.V.; Rodionov, V.Ye.; Tzyrkunov, Yu.A. X-ray and atomic force microscopy techniques were used for investigations of crystalline structure and nano-morphology of ZnS:Cu thin films. The films were deposited by electron beam evaporation on substrates of various types (glass, BaTiO₃, silicon). New non-vacuum method of annealing was applied for improvement electro-physical parameters of ZnS:Cu based thin film electroluminescent devices. The annealing was carried out at the temperature of 850 °C. Ga co-doping was applied for the same structures in the course of the annealing process. It was shown that recrystallization process at annealing leads to improvement of ZnS:Cu films structural perfection without changes of crystal structure. This improvement provides tenfold increase of photo- and electroluminescence brightness and decrease of threshold voltage down to 10 V, as well as enhancement of device stability against degradation. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119243 2001-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119242 Using non-organic resist based on As-S-Se chalcogenide glasses for combined optical/digital security devices Kostyukevych, S.A.; Moskalenko, N.L.; Shepeliavyi, P.E.; Girnyk, V.I.; Tverdokhleb, I.V.; Ivanovsky, A.A. Modern holographic protective elements used as emblems against counterfeiting are being more complicated as they should oppress criminal world. 2D, 3D, 3D rainbow holograms or simple diffraction structures protecting documents can not be acceptable against illegal copying of important documents, bank notes or valuable products. Recent developments in technology of Optical variable devices permit world leaders to create more advanced security elements: Kinegrams™, Exelgrams™, Pixelgrams™, Kineforms™. These products are used for protecting the most confidential documents and bank notes, but now even their security level can not be enough, and besides their automatic identification is vulnerable to factors of instability. We elaborate new visual security devices based on the usage of expensive and advanced technology of Combined optical/digital security devices. The technology unites digital and analog methods of synthesis and recording Visual security devices. The analog methods include technique of optical holography - different combinations of 2D/3D, 3D, 2D/3D + 3D structures. Basing on them the design with elements of 3D graphic including security elements and hidden machine-readable images are implemented. The digital methods provide synthesis of Optical Variable Devices including special security elements, computer generated holograms and Kineforms™. Using them we create determined and quasi-random machine-readable images. Recording are carried out using the combined optical and electron-beam submicrometer technology. The results obtained show effectiveness of the combined technology permitting to increase the security level essentially that should increase tamper and counterfeit resistance for many years. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119242 2001-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119241 Optical biosensors based on the surface plasmon resonance phenomenon: optimization of the metal layer parameters Snopok, B.A.; Kostyukevich, K.V.; Lysenko, S.I.; Lytvyn, P.M.; Lytvyn, O.S.; Mamykin, S.V.; Zynyo, S.A.; Shepelyavyj, P.E.; Kostyukevich, S.A.; Shirshov, Yu.M.; Venger, E.F. Application of the evanescent wave phenomena (e.g. surface plasmon resonance) in the chemical and biochemical sensors provides both optimal conditions for registration of specific interactions and high sensitivity. At the same time, the stability and reproducibility of parameters of a thin gold film (where the plasmon oscillations occur) are key problems for both (i) optimal transformation of biochemical information into the signal that is convenient for further treatment and (ii) the formation of artificial interfacial architectures. The paper presents results concerning the study of the deposition process temperature regimes influence on optical properties and structure of thin gold films. Morphological and topographic features of the thin film structures were analyzed using X-ray diffraction and atomic force microscopy, respectively. It is shown that the simple procedure of the low temperature annealing (at ~ 120°C) provides optimum parameters of thin gold films in view of their application as physical transducers in optical biosensors. Finally, the SPR transducer was fabricated with high sensitive elements used in the device «PLASMON-4M» elaborated in the Institute of Semiconductor Physics (NAS of Ukraine). Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119241 2001-01-01T00:00:00Z