Thermo-and photostimulated luminescence of CaI2-based crystals.

We systematize earlier and new data on the effect of oxygen and hydrogen impurities on recombination processes in CaI2 crystals by jointly examining their roentgeno-, thermo-, and photostimulated luminescence spectra. The 90-K emission spectra of CaI2 crystals are shown to consist of at least five bands. The 395-nm emission is assumed to be due to radiative decay of (HI)* heteronuclear excitons. The 520-nm luminescence is attributable to iodine-vacancy-bound anion excitons. The thermostimulated luminescence peaks observed in the temperature range 90–150 K are due to the thermal dissociation of V k and H hole centers. The 90-K photostimulated luminescence of CaI2-based crystals is shown to be excited in the electronic stage of the recombination process. [ABSTRACT FROM AUTHOR]