Polarized luminescence and transient optical absorption induced by pulsed electron irradiation of crystals were studied. Exponential stages with decay times of 6.5ms were observed to exist in luminescence bands at 4.0, 5.0 and 6.7eV, which coincide in spectral composition and polarization characteristics with the luminescence of self-trapped excitons of 2 types. The formation efficiency of centers with a 6.5ms decay time was comparable to that of triplet self-trapped excitons. The general characteristics of the kinetics and the decay times of the transient optical absorption of these centers did not depend upon electron fluence and were governed by the monomolecular recombination process. The spectra of transient optical absorption centers with a decay time of 6.5ms were found to be similar to those of V-type hole centers and self-trapped exciton hole components. The mechanism by which recombination of closely spaced, spatially correlated Frenkel pairs, Be+ and V– centers, brings about an exponential component with a 6.5ms decay time in the luminescence of self-trapped excitons of 2 types in BeO was considered.

Excitation of Self-Trapped-Exciton Luminescence in the Recombination of Frenkel Defects in BeO. S.V.Gorbunov, V.Y.Yakovlev: Physics of the Solid State, 2005, 47[4], 627-31