Effect of rare-earth doping on the free-volume structure of Ga-modified Te20As30Se50 glass

Ya. Shpotyuk (1, 2) , A. Ingram (3) , O. Shpotyuk (4) , Catherine Boussard-Plédel (5) , Virginie Nazabal (5) , Bruno Bureau (5)

1 Ivan Franko National University of Lviv
2 Rzeszow University of Technology
3 Opole University of Technology
4 Institute of Physics [Jan Dlugosz University in Częstochowa]
5 ISCR - Institut des Sciences Chimiques de Rennes

By exploring the positron-electron annihilation technique in positron lifetime measuring mode, it is shown that principal rare-earth (RE) induced structural reconfiguration in Ga-codoped TAS-235 glass (that is a glassy Te20As29Ga1Se50 alloy) is related to occupation of intrinsic free-volume voids by embedded RE ions tightly connected with Ga-based tetrahedrons via strong covalent RE-Se/Te-Ga links. A gradual decrease in the intensity of the second component of two-term decomposed lifetime spectra of annihilating positrons accompanied with a detectable increase in the defect-related positron lifetime (thus inducing essentially a depressed rate in positron trapping) is evidenced by the example of Pr3+ ions added homogeneously to Te20As29Ga1Se50 glass in the amount of 500 ppmw. Observed changes in positron lifetime spectra are explained in terms of the competitive contribution of different occupancy positions in Ga-codoped glass available for RE ions and trapped positrons.

Keywords: semiconductors; active applications; bond approach; Chalcogenide glasses; Defects; IR; lifetime; photonics; positron-annihilation; progress

Domains: Chemical Sciences; Material chemistry; Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]

Ya. Shpotyuk, A. Ingram, O. Shpotyuk, Catherine Boussard-Plédel, Virginie Nazabal, et al.. Effect of rare-earth doping on the free-volume structure of Ga-modified Te20As30Se50 glass. RSC Advances, 2016, 6 (27), pp.22797-22802. ⟨10.1039/c6ra02092e⟩. ⟨hal-01298761⟩