Luminescent protection against radiation damage in wide-gap materials

Abstract

In 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 2O 3:Sc 3+ and Al 2O 3:Gd 3+) or to intrinsic defects (F and F + centers induced by the previous irradiation of Al 2O 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.