Luminescent protection against radiation damage in wide-gap materials

In the wide-gap metal oxides, with Eg 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 Al2O3:Sc3+ and Al2O3:Gd3+) or to intrinsic defects (F and F+ centers induced by the previous irradiation of Al2O3 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.