title: Free-Volume Nanostructurization in Ga-Modified As2Se3 Glass.
abstract: Different stages of intrinsic nanostructurization related to evolution of free-volume voids, including phase separation, crystalline nuclei precipitation, and growth, were studied in glassy As2Se3 doped with Ga up to 5 at. %, using complementary techniques of positron annihilation lifetime spectroscopy, X-ray powder diffraction, and scanning electron microscopy with energy-dispersive X-ray analysis. Positron lifetime spectra reconstructed in terms of a two-state trapping model testified in favor of a native void structure of g-As2Se3 modified by Ga additions. Under small Ga content (below 3 at. %), the positron trapping in glassy alloys was dominated by voids associated with bond-free solid angles of bridging As2Se4/2 units. This void agglomeration trend was changed on fragmentation with further Ga doping due to crystalline Ga2Se3 nuclei precipitation and growth, these changes being activated by employing free volume from just attached As-rich glassy matrix with higher content of As2Se4/2 clusters. Respectively, the positron trapping on free-volume voids related to pyramidal AsSe3/2 units (like in parent As2Se3 glass) was in obvious preference in such glassy crystalline alloys.
authors.affiliation: Department of Electronics, Ivan Franko National University of Lviv, 107, Tarnavskogo str., 79017, Lviv, Ukraine. yashpotyuk@gmail.com.|Centre for Innovation and Transfer of Natural Sciences and Engineering Knowledge, University of Rzeszow, 1, Pigonia str., 35-959, Rzeszow, Poland. yashpotyuk@gmail.com.|Laboratoire Verres et Céramiques, UMR-CNRS 6226, Université de Rennes 1, 35042, Rennes, Cedex, France. yashpotyuk@gmail.com.
authors.forename: Ya
authors.initials: Y
authors.lastname: Shpotyuk
authors.affiliation: Opole University of Technology, 75, Ozimska str., 45370, Opole, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Ingram
authors.affiliation: Vlokh Institute of Physical Optics, 23, Dragomanov str., 79005, Lviv, Ukraine.|Institute of Physics, Jan Dlugosz University, 13/15, Armii Krajowej al., 42200, Czestochowa, Poland.
authors.forename: O
authors.initials: O
authors.lastname: Shpotyuk
authors.affiliation: Centre for Innovation and Transfer of Natural Sciences and Engineering Knowledge, University of Rzeszow, 1, Pigonia str., 35-959, Rzeszow, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Dziedzic
authors.affiliation: Laboratoire Verres et Céramiques, UMR-CNRS 6226, Université de Rennes 1, 35042, Rennes, Cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Boussard-Pledel
authors.affiliation: Laboratoire Verres et Céramiques, UMR-CNRS 6226, Université de Rennes 1, 35042, Rennes, Cedex, France.
authors.forename: B
authors.initials: B
authors.lastname: Bureau
keywords: Chalcogenides; Crystallization; Nanostructurization; Phase separation; Positron annihilation lifetime spectroscopy