Defects and luminescence in pure and i-doped agbr crystals

A main emission band appeared in the pure and lightly I-doped samples at 2.5 eV. The decay times of the luminescence pulse were 16 and 30 μsec in the pure and doped samples respectively. The temperature dependence of the decay time, the thermal activation energy and the halfwidth of the 2.5 eV emission of the doped samples also differed from those of the pure crystals. These difference indicate that the process responsible for the emission in the pure crystals differs from that in the I-doped samples. The 2.5 eV emission in the pure crystals may be due to a radiative decay of an exciton bound to an intrinsic defect. This is supported by the recorded effects of thermal treatment and of plastic deformation on this emission in the pure crystals.