Luminescent protection against radiation damage in wide-gap materials

Abstract

a b s t r a c tIn the wide-gap metal oxides, with E g lower than the formation energy of a pair of Frenkel defects, hot recombination of nonrelaxed electrons and holes cause the creation of defects under the conditions of high-density excitation. Novel manifestations of the fast direct energy transfer by hot electrons to impurity centers (e.g., in Al 2 O 3 :Sc 3+ and Al 2 O 3 :Gd 3+ ) or to intrinsic defects (F and F + centers induced by the previous irradiation of Al 2 O 3 with swift heavy ions) have been revealed using the methods of low-temperature cathodo-and photoluminescence. The contribution of the solid-state analogue of the Franck-Hertz effect as well as of the multiplication processes of electronic excitations to the suppression of hot recombination and the increase of radiation resistance of dielectrics has been analysed.

On the mechanisms of radiation damage and prospects of their suppression in complex metal oxides

“…The idea of such luminescent protection against hot e–h recombination in WGMs was suggested in Ref. 31, 51.…”

Luminescence properties of undoped LiBaAlF6single crystals

“…Delocalization of charge carriers above 200 K may prevent defect formation as their mobility ensures efficient radiative dissipation of energy absorbed in a crystal by means of luminescence. Such a protection mechanism functioning in wide gap crystals has been proposed recently [27]. Further studies are required to understand the origin of three related processes: emission at 3.0 eV, radiation-induced defects' influence and depopulation of traps at T = 200 K.…”

Photoinduced Br Desorption from CsBr Thin Films Grown on Cu(100)

“…Surface F centers can be excited by hot electrons photoemitted from the Cu substrate and traveling in the CsBr conduction band, an analogue of the so-called Franck-Hertz effect in solids. 59 The excitation of F-center electrons by electrons in the conduction band in Al 2 O 3 has been extensively studied, 60 as has the luminescence behavior of electron-excited Ag + and Tl + impurity ions in similar alkali halides such as RbCl and KCl. 61,62 Alternative Br Desorption Pathways.…”