Facultatea de Fizică şi Inginerie / Faculty of Physics and Engineering

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1998 - 199912000 - 20072

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Author: search.filters.author.Ivanova, G.N.Has files: Yes

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    The structure of high-temperature blue luminescence centers in zinc selenide and mechanisms of this luminescence [Articol]
    (Springer Nature, 1998) Ivanova, G.N.; Kasiyan, V.A.; Nedeoglo, Dmitrii; Nedeoglo, Natalia; Simashkevich, A.V.
    The characteristic features of temperature quenching of the intensity of the edge luminescence bands of n-ZnSe crystals annealed in different media (vacuum, Zn, Se) are investigated a wide temperature range. A change in the mechanisms of high-temperature exciton luminescence in the short-wavelength region of the spectrum (443 nm) with increase in temperature of the crystal is observed. It is shown that the nature of temperature quenching of the long-wavelength edge luminescence band (458 nm) is evidence of dissociation of associative luminescence centers with increase in the sample temperature.
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    Interaction of intrinsic defects with impurities in Al doped ZnSe single crystals [Articol]
    (American Institute of Physics, 2007) Ivanova, G.N.; Nedeoglo, Dmitrii; Nedeoglo, Natalia; Sirkeli, Vadim
    We report on the results of a complex study of electrical (77−300 K) and luminescence (10−300 K) properties of 𝑛-ZnSe single crystals annealed in a Zn melt containing Al impurity at concentrations ranging from 0.1 to 80 at. %. It was established that Al atoms form donor centers only at a low impurity concentration (≤0.5 at. %). The increase of the amount of Al atoms in the crystal results in the formation of (VZnAlZn) associative acceptor centers leading to the self-compensation of the shallow Al donor impurity. This process is accompanied by the emergence and development of a self-activated luminescence band associated with the (VZnAlZn) acceptor centers. We show that further increase of the Al content in the melt (≥10 at. %) leads to the dissociation of the acceptor complexes and to a recurrent donor doping effect. The photoluminescence spectra of such crystals are dominated by activated luminescence via the (CuZnVSeCu𝑖) and (CuZnAlZn) associative centers.
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    Photoluminescence of n-ZnSe single crystals doped with iodine by vapour phase diffusion [Articol]
    (2006) Avdonin, A.N.; Nedeoglo, Dmitrii; Nedeoglo, Natalia; Sirkeli, Vadim; Ivanova, G.N.
    Photoluminescence spectra of n-ZnSe single crystals doped with iodine are investigated in the temperature range from 83 to 300 K. It is shown that the edge PL band is formed by overlapping of the PL lines attributed to ISe donor-bound ecxitons (I2I) and VZn acceptorbound excitons (D1I). A model of radiation mechanisms, which explain the redistribution of the edge and long-wave PL bands intensities with increasing doping level of the samples, is proposed.