2. Articole

Permanent URI for this collectionhttps://msuir.usm.md/handle/123456789/47

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Author: search.filters.author.Nedeoglo, DmitriiSubject: search.filters.subject.ZnSe

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    PURIFICATION OF ZNSE CRYSTALS FROM ELECTRICALLY ACTIVE BACKGROUND IMPURITIES BY YTTERBIUM DOPING
    (John Wiley & Sons, 2014) Radevici, Ivan; Sushkevich, Konstantin; Sirkeli, Vadim; Nedeoglo, Dmitrii; Nedeoglo, Natalia; Huhtinen, Hannu; Paturi, Petriina
    Hall coefficient, electrical conductivity, and electron mobility are investigated for n-ZnSe:Yb single crystals with high concentration of electrically active background impurities
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    OBTAINING OF II-VI COMPOUND SUBSTRATES WITH CONTROLLED ELECTRICAL PARAMETERS AND PROSPECTS OF THEIR APPLICATION FOR NANOPOROUS STRUCTURES
    (John Wiley & Sons, 2014) Colibaba, Gleb; Goncearenco, Evghenii; Nedeoglo, Dmitrii; Nedeoglo, Natalia; Monaico, Eduard; Tiginyanu, Ion
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    MAGNETIC AND LUMINESCENT PROPERTIES OF NICKEL-DOPED ZnSe CRYSTALS
    (Elsevier, 2015) Sirkeli, Vadim; Radevici, Ivan; Sushkevich, Konstantin; Nedeoglo, Natalia; Nedeoglo, Dmitrii
    Magnetic and photoluminescent properties of nickel-doped ZnSe crystals with impurity concentrations varied by changing the Ni amount in the source material from 0.001 to 0.50 at.% are studied in 5–300 K temperature range. Investigation of magnetic properties shows that Ni impurity in ZnSe forms isolated paramagnetic centers and probability of Ni–Ni pairs formation is negligible due to low Ni concentration in the samples. The contribution of Ni impurity to edge emission and its influence on infra-red emission are discussed. It is found that complete concentration quenching of luminescence within all studied spectral range is observed starting with Ni concentration of 0.50 at.%.
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    INFRARED PHOTOLUMINESCENCE OF ZnSe:GD CRYSTALS
    (Elsevier, 2015) Colibaba, Gleb; Goncearenco, Evghenii; Nedeoglo, Dmitrii; Nedeoglo, Natalia
    Photoluminescent and optical properties of ZnSe crystals doped with Gd impurity are investigated in infrared (IR) spectral range. The influence of crystal growth temperature, impurity concentration, stoichiometric deviation and post-annealing cooling rate, concentration of Cr and Cu background impurities, temperature and excitation level on photoluminescent and optical properties of the samples is studied. Based on these investigations, the structure of complex IR photoluminescence (PL) bands is analyzed. Correlation between the component parts of the bands at 1 and 2 µm is found and possibility to control the IR PL spectra by enrichment of the samples with Zn or Se is discussed. Coincidence of the IR PL spectra structure is shown for the samples doped with Gd, Yb, and Cr impurities. The model that explains the formation of complexes based on rare-earth elements (REEs) and Cr and Cu background impurities fixed in the nodes of crystal lattice with tetrahedral symmetry, responsible for IR PL bands, is proposed.
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    PHOTOLUMINESCENCE OF ZnSe SAMPLES DOPED WITH ANTIMONY AND IODINE
    (Elsevier, 2021) Sushkevich, Konstantin; Goncearenco, Evghenii; Nedeoglo, Natalia; Nedeoglo, Dmitrii
    Photoluminescence (PL) spectra of ZnSe samples grown by Chemical Vapour Transport (CVT), Physical Vapour Transport (PVT), and from melt have been studied in the temperature range from 100 to 300 K. Impurity-defect composition of the studied samples was varied by doping with antimony (Sb) or iodine (I), as well as co-doping with Sb and I, both during the crystal growth and crystal annealing in the respective melts. It is established that the PL band with maximum at (570–580) nm is present only in the spectra for ZnSe samples co-doped with Sb and I, independent of growth technique mand doping method. The (SbSe–ISe) radiative centre, with the energy level placed 0.5 eV above the valence band top, is proposed to be responsible for this PL band.
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    SIMULATION ET MODELISATION DE LA VARIATION DE LA MOBILITE DE HALL DES PHOTOELECTRONS EN FONCTION DE LA TEMPERATURE DANS LES CRISTAUX DE n-ZnSe :Zn IRRADIES AVEC DES ELECTRONS ENERGETIQUES
    (Université Mentouri, 2007) Djouadi, D.; Boughiden, B.; Chelouche, A.; Nedeoglo, Dmitrii
    Dans l’intervalle de températures [77..300 K] a été mesurée la mobilité de Hall des électrons d’équilibre et des photoélectrons dans les cristaux de n-ZnSe :Zn irradiés avec un faisceau d’électrons d’énergie E=1,3 MeV et dont la dose d’irradiation varie entre 2,73 1016 et 5.19 1017 électrons/cm2 . Le comportement de la mobilité des photoélectrons s’explique parfaitement dans le cadre d’un modèle à deux-barrières d’un semiconducteur inhomogène représentant une matrice faiblement ohmique contenant des inclusions fortement ohmiques (clusters). En se basant sur les théories de Shik et de Petrossiyan , une expression approximative de la mobilité de Hall a été obtenue. Il a été montré que ce modèle fonctionne parfaitement pour les petites doses d’irradiation. Lorsque la dose dépasse une certaine valeur critique ( D= 2.98 1017 électrons /cm2) le modèle considéré passe au modèle du potentiel à relief aléatoire.