PAL spectroscopy of rare-earth doped Ga–Ge–Te/Se glasses. (April 2016)

• Record Type: Journal Article
• Authors: Shpotyuk, Ya.; Ingram, A.; Shpotyuk, O.
• Is Part Of: Journal of physics and chemistry of solids. Volume 91(2016:Apr.)
• Page Start: 76
• Page End: 79
• Publication Date: 2016-04
• Subjects: Chalcogenides -- Glasses -- Positron annihilation spectroscopy -- Defects -- Microstructure; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2015.12.010
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: Positron annihilation lifetime (PAL) spectroscopy was applied for the first time to study free-volume void evolution in chalcogenide glasses of Ga–Ge–Te/Se cut-section exemplified by glassy Ga10 Ge15 Te75 and Ga10 Ge15 Te72 Se3 doped with 500 ppm of Tb 3+ or Pr 3+ . The collected PAL spectra reconstructed within two-state trapping model reveal decaying tendency in positron trapping efficiency in these glasses under rare-earth doping. This effect results in unchanged or slightly increased defect-related lifetimes τ 2 at the cost of more strong decrease in I 2 intensities, as well as reduced positron trapping rate in defects and fraction of trapped positrons. Observed changes are ascribed to rare-earth activated elimination of intrinsic free volumes associated mainly with negatively-charged states of chalcogen atoms especially those neighboring with Ga-based polyhedrons. Highlights: Positron annihilation spectroscopy to study rare-earth doping in Ga–Ge–Te/Se glasses. Two-state trapping model to reconstruct experimental positron lifetime spectra. Decaying tendency in positron trapping efficiency in glasses under rare-earth doping. Rare-earth activated elimination of free-volume voids related to Ga-tetrahedrons.