Nanosecond-resolution absorption spectroscopy at room temperature was used to study the laws governing the creation and evolution of the primary defect structure in CaF2, SrF2, and BaF2 crystals exposed to an accelerated electron pulse. It is shown that the spectral-kinetic characteristics of self-trapped excitons created in undamaged parts of the crystal lattice are qualitatively similar. Partial polarization of the absorption of self-trapped excitons is observed in CaF2. The structure of the transient absorption spectra becomes more complex in the sequence CaF2, SrF2, BaF2 because of the formation of excitons trapped in phase inclusions of homologous cationic impurities. The spectral characteristics of excitons trapped in undamaged parts of the CaF2 and SrF2 lattice and in their phase inclusions in BaF2 are the same although the latter have a considerably shorter relaxation time. Short-lived (τ ≤ 100 ns) absorption of unknown defects was observed in the spectral range ≥ 5 eV.
|Журнал||Physics of the Solid State|
|Состояние||Опубликовано - июл 1998|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics