Effect of Rare-Earth Doping on Free-Volume Nanostructure of Ga-Codoped Glassy (As/Sb)Se.

Subsequent stages of atomic-deficient nanostructurization finalizing rare-earth functionality under Pr-doping in Ga(AsSbSe) glass are studied employing method of positron annihilation lifetime spectroscopy. Genesis of free-volume positron trapping sites, composed of atomic-accessible geometrical holes (void cores) arrested by surrounding atomic-inaccessible Se-based bond-free solid angles (void shells), are disclosed for parent AsSe, Ga-codoped Ga(AsSe), as well as Ga-codoped and Sb-modified Ga(AsSbSe) glasses. The finalizing nanostructurization due to Pr-doping (500 wppm) in glassy Ga(AsSbSe) is explained in terms of competitive contribution of changed occupancy sites available for both rare-earth ions and positrons.