Peculiarities of intrinsic luminescence excited by pulsed electron beam in CsI and CsI:CO3

The spectra and decay kinetics of STE luminescence arising under a pulsed electron beam (Еex=0.25 MeV, t1/2=15 ns, W=3 mJ/cm2) in CsI and CsI:8.3·10-3CO3 mol% within a temperature range of 80 K÷ 450 K, are examined. It is found that carbonate ions cause a drastic shortening of the intrinsic luminescence decay time at room temperature. The observed distinction in the UV-luminescence decay kinetics of CsI and CsI:CO3 is due to different temperature behavior of the decay time τslow in the slow stage of the exponential decay kinetics at temperatures above 200 K. The presented results are interpreted in terms of the existence of “off-center” excitons with different structure morphology in CsI lattice.