Articole ştiinţifice: Recent submissions

  • Fresnel lens-type energy concentrator for space-based solar power systems 
    SERGENTU, Vladimir; URSAKI, Veacheslav; IOIŞER, Anatolii; ADAR, Eliezer (Romanian Academy Publishing House, 2018)
    In this paper a new concept of designing Fresnel lens concentrators on the basis of magnetic microwires with a complex spatial distribution of their density is proposed. The optical properties of microwires are analyzed ...
  • Solar energy concentrators in geostationary orbits 
    SERGENTU, Vladimir; URSAKI, Veacheslav; IOIŞER, Anatolii; ADAR, Eliezer (Romanian Academy Publishing House, 2019)
    An important component of Space-based solar power (SBSP) systems is the solar energy concentrator that collects solar power in space and focusses it on solar cells or heat engines to produce electricity, which is consequently ...
  • The contribution of exciton-phonon interaction and action disorder to near-band-edge extrinsic absorption in II-III2-VI4 compounds 
    GEORGOBIANI, A. N.; URSAKI, V. V.; RADAUTSAN, S. I.; TIGINYANU, I. M. (ELSEVIER, 1985)
    Results of a study of near-band-edge absorption in both initial and annealed CdGa2S4 and CdIn2S4 single crystals at different temperatures are presented. Exciton-phonon interaction and cation disorder are shown to determine ...
  • Raman scattering study of Zn/sup +//P/sup +/ co-implanted GaAs single crystals 
    URSAKI, V. V.; ICHIZLI, V. M.; TIGINYANU, I. M.; TERLETSKII, A. I.; CALUJA, Y. I.; RADAUTSAN, S. I. (IEEE, 1995)
    The activation efficiency of zinc impurity co-implanted with P/sup +/ ions in GaAs single crystals was studied by Raman scattering (RS) at phonon-plasmon coupled modes. P/sup +/ co-implantation has been found to result in ...
  • Photocatalytic indium-tantalum-oxide and its photoluminescence 
    KANTSER, V.; MUNTEAN, S.; ZHITAR, V.; VOLODINA, G.; KAPLIN, V.; URSAKI, V. (Institutul de Inginerie Electronică şi Nanotehnologii "D. Ghiţu" al AŞM, 2003)
    Both bulk ceramic and powder like samples In0,9Ni0,1TaO4 photocatalytic semiconductor oxides have been obtained by the method of solid phase reactions. The photocatalytic activity on water splitting has been investigated ...
  • Preparation and photoluminescence of ZnGa2O4:Co 
    ZHITAR, V.; URSAKI, Veacheslav; VOLODINA, Galina; MUNTEAN, Ştefan; SHEMYAKOVA, Tatiana (Institutul de Inginerie Electronică şi Nanotehnologii "D. Ghiţu" al AŞM, 2007)
    Ceramic samples of ZnGa2O4 doped with Co have been prepared. Their photoluminescence = 351 nm) and various temperatures (10 – 300 K)spectra measured at laser excitation (λ contain a wide band, centered at 2.8 eV (10 K) ...
  • Exciton–phonon luminescence and Raman scattering in CuGaS2 crystals 
    SYRBU, N. N.; TEZLEVAN, V. E.; GALBICH, I.; NEMERENCO, L. L.; URSAKI, V. V. (ELSEVIER, 2009)
    Photoluminescence and resonance Raman scattering spectra of CuGaS2 crystals are investigated at low temperature (10K) under the excitation with the radiation from a spectral interval obtained by passing the radiation of ...
  • Energy band structure and optical constants of ZnAs2 crystals 
    STAMOV, I. G.; SYRBU, N. N.; URSAKI, V. V.; DOROGAN, A. V. (ELSEVIER, 2012)
    The fine structure of the Fabry–Perot interference as well as the interference of ordinary and extraordinary waves is investigated in ZnAs2 crystals. ε1, ε2, n and k optical constants are calculated in a wide spectral range ...
  • Interference of ordinary and extraordinary waves in AgAsS2 crystals 
    SYRBU, N. N.; STAMOV, I. G.; URSAKI, V. V.; PARVAN, V.; IVANENCO, Yu. (ELSEVIER, 2012)
    The anisotropy of the near-bandgap absorption is investigated in AgAsS2 crystals. The refraction indices, n and n respectively for the Ec and Ec polarizations as well as the spectral dependence of the refraction ...
  • Optical spectra and energy band structure of AgAsS2 crystals 
    STAMOV, I. G.; SYRBU, N. N.; URSAKI, V. V.; PARVAN, V. (ELSEVIER, 2012)
    Ground and excited states of three exciton series are observed in the region of fundamental absorption edge of AgAsS2 crystals. The contours of exciton reflection spectra are calculated and the main parameters of excitons ...
  • Resonance Raman scattering and excitonic spectra in TlInS2 crystals 
    ZALAMAI, V. V.; STAMOV, I. G.; SYRBU, N. N.; URSAKI, V. V.; DOROGAN, V. (ELSEVIER, 2015)
    The excitons ground and excited states for Ea and Eb polarizations in absorption and reflection spectra of TlInS2 crystals were detected. The fundamental parameters of excitons and bands were determined at k=0. The ...
  • Sharp variations in the temperature dependence of optical reflectivity from AlN/GaN heterostructures 
    URSAKI, V. V.; TIGINYANU, I. M.; SYRBU, N. N.; ZALAMAI, V. V.; HUBBARD, S.; PAVLIDIS, D. (IOP Publishing, 2002)
    Sharp variations in optical reflectivity were observed when cooling and heating AlN/GaN heterostructures on sapphire substrates between room temperature and 10 K. The reflectivity was found to decrease at a definite ...
  • Cathodoluminescence characterization of rare earth doped composite materials based on porous GaP 
    SÁNCHEZ, B.; MÉNDEZ, B.; PIQUERAS, J.; SIRBU, L.; TIGINYANU, I. M.; URSAKI, V. V. (Springer Nature Switzerland, 2008)
    Porous GaP layers doped with erbium or europium elements have been obtained by electrochemical etching and further impregnation processes. The thermal treatments for optical activation of rare earth (RE) ions lead to partial ...
  • Resonance Raman scattering in CuGaxAl1-xS2crystals 
    SYRBU, N. N.; TIGINYANU, I. M.; URSAKI, V. V.; DOROGAN, A. V. (IOP Publishing, 2008)
    The change of polarization of the resonant Raman scattering lines is studied in CuGaxAl1−xS2 crystals with x equal to 1, 0.95 and 0.9 assuming resonance conditions with 4880 and 4765 Å Ar laser lines. Linear and circular ...
  • Impurity centers in ZnSe:Na crystals 
    COLIBABA, G. V.; NEDEOGLO, D. D.; URSAKI, V. V. (ELSEVIER, 2011)
    The influence of sodium impurity on photoluminescence (PL) spectra of ZnSe crystals doped in a growth process from a Se+Na melt is investigated. It is shown that the introduction of the impurity results in emergence of ...
  • A comparative study of Cu-related Pasmonic effects in electrochemically nanostructured CuInSe2 and CuGaSe2 crystals 
    URSAKI, Veacheslav (Institutul de Inginerie Electronică şi Nanotehnologii "D. Ghiţu" al AŞM, 2013)
    We study the differences in electrochemical nanostructuring of CuInSe2 and CuGaSe2 crystals. To make the crystals suitable for electrochemical nanostructuring, they are subjected to thermal treatment either in vacuum or ...
  • A comparative study of plasmonic effects in electrochemically nanostructured CuInS2 and CuGaS2 crystals 
    URSAKI, Veacheslav (Institutul de Inginerie Electronică şi Nanotehnologii "D. Ghiţu" al AŞM, 2014)
    We investigate the differences in electrochemical nanostructuring of CuInS2 and CuGaS2 crystals. It is shown that thermal treatment of CuInS2 crystals either in vacuum or in Zn vapors is a procedure providing necessary ...
  • Temperature dependence of the photoluminescence spectra in AgGaS2 
    RICCI, P. C.; ANEDDA, A.; CORPINO, R.; CARBONARO, C. M.; MARCEDDU, M.; TIGINYANU, I. M.; URSAKI, V. V. (ELSEVIER, 2005)
    The Silver Gallium Sulfide (AgGaS2) ternary compound is a wide bandgap semiconductor (about 2.7eV) whose photoluminescence properties are characterized by excitons and donor–acceptor pairs recombinations. We have performed ...
  • Optical spectra in the region of exciton resonances in quantum wells and quantum dots of In0.3Ga0.7As/GaAs heterostructures 
    SYRBU, N. N.; DOROGAN, V.; DOROGAN, A.; VIERU, T.; URSAKI, V. V.; ZALAMAI, V. V. (ELSEVIER, 2012)
    The transparency, reflection and luminescence spectra of In0.3Ga0.7As structures with 8nm thickness and quantum wells limited by the barrier layer GaAs of a 9nm (upper layer) and 100nm (bottom layer) thickness had been ...
  • Luminescent and Photoconductive Properties of AgGa2.5In2.5S8 and CuGa2.5In2.5S8 New Semiconductors 
    ANEDDA, A.; SERPI, A.; MOLDOVYAN, N. A.; TIGINYANU, I. M.; URSAKI, V. V. (IOP Publishing, 1993)
    Results of a complex study of photoluminescence (PL), photoconductivity (PC) and photo-voltaic (PV) spectra in AgGa2.5In2.5S8 and CuGa2.5In2.5S8 single crystals are presented. The values of indirect (Egi=2.25 eV) and direct ...

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