Behavior of trapped electronic excitations in oxide crystals

The transient optical absorption spectra and their decay kinetics have been investigated by time-resolved absorption spectroscopy technique in Zn-dope d BeO crystals. Comparing transient optical absorption properties of self-t rapped excitons (STEs) and Zn-impurity-trapped excitons we have made conclu sions about the similarity of their hole components and distinctive peculia rities of forbidden optical transitions in their electron components. The m etastable optical absorption of Zn+-centers has been first found. It is sho wn that the Zn-impurity-trapped exciton formation occurs at the hole stages of recombination thermotunnel processes with the participation of electron Zn+-centers. It is found that high probability of electron and hole center recombination formed in BeO-Zn crystals by electron pulses may be related to a high degree of their space correlation.