Browsing by Author "Cuculescu, Elvira"

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    Optical properties of crzstals GaSe and InSe doped with Cu [Articol]
    (2005) Evtodiev, Igor; Cuculescu, Elvira; Caraman, Mihail; Anghel, Sergiu; Petrov, M.
    The anisotropy of absorption spectra in the range of the margin of fundamental band of the crystals GaSe and InSe doped with Cu in the percentage quantities up to 0.5 % at. from which the implementation mechanism of the impurity atoms of Cu in the hexagonal crystal grating of the GaSe and InSe crystals and the localization energy of the impurity levels in the forbidden energetic band is studied.
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    Study of recombination mechanisms in crystals GaSe doped with Cu, Cd AND Sn [Articol]
    (2005) Evtodiev, Igor; Cuculescu, Elvira; Rusu, Marin; Caraman, Mihail
    The stratified crystals of GaSe type serve as the basic element in different optoelectronic devices such as the micro lasers (the excitation with the electron beam), optoelectronic modulators for a large domain of wavelengths [1]. In order to enlarge the domain of application of gallium monoselenium and of analogical compounds by the structure and physical mechanical properties (GaS and InSe) it is necessary to increase the variety of characteristic physical properties of these compounds. The studies of optical properties and photoelect rical ones of the crystals GaS, GaSe and InSe pure nondoped prove that on their base the optoelectronic devices can be elaborated for the visible range and the near IR. In order to reach the conquerable parameters with the existent elaborations (on the base of semiconductors AIIBVI, AIIIBVI) it is neessary to vary controllably with the diagram of localized states in the forbidden band of these crystals. It is known [2] that the impurity atoms in the crystals of GaSe type, after the liquidation of structural defects in the sub grid of the metal from the interior of stratified packages Hal-M-M-Hal are localized in the space among the planes of the neighbor packages contributing so to the increasing of cohesion force among packages. These atoms will be situated on the surface of cleaving on the direction perpendicular to C contri buting so to the formation of the ionized surface states. The physical properties of the extra fine monocrystalline films are modified by the surface states in which the characteristic properties of the structures with the reduced sizes are manifested.