Nanoscale mechanism of rare-earth doping in Ga-codoped glassy As-Sb selenides

Abstract : The method of annihilating positrons in positron annihilation lifetime measuring mode is applied to study mechanism of rare-earth doping in Ga-codoped arsenic selenide As2Se3 glass modified with Sb. The atomic-deficient structure of parent As2Se3 glass is imagined as containing positron-trapping sites in the form of free-volume voids within cycle-type arrangement of corner-sharing trigonal AsSe3/2 pyramids, composed of atomic-accessible geometrical holes arrested by surrounding atomic-inaccessible Se-based bond-free solid angles. The Ga codoping in As2Se3 glass causes gradual decrease in trapping rate and fraction of trapped positrons due to agglomeration of free-volume voids. Partial As-to-Sb replacement in Ga-codoped As-Se glasses leads to better stability against crystallization processes and possibility to further rare-earth doping without principal changes in the type of positron-trapping defects. Effect of 500wppm of Pr3+ in Ga-2(As0.28Sb0.12Se0.60)(98) glass is explained in terms of competitive contribution of changed occupancy sites in Ga-modified glassy network available for rare-earth ions and annihilating positrons.
Type de document :
Article dans une revue
Journal of the American Ceramic Society, Wiley, 2017, 100 (9), pp.3865-3874. 〈10.1111/jace.14909〉
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Soumis le : mercredi 11 octobre 2017 - 14:00:35
Dernière modification le : samedi 24 mars 2018 - 01:42:35

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Yaroslav Shpotyuk. Nanoscale mechanism of rare-earth doping in Ga-codoped glassy As-Sb selenides. Journal of the American Ceramic Society, Wiley, 2017, 100 (9), pp.3865-3874. 〈10.1111/jace.14909〉. 〈hal-01614772〉

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