Luminescence of V-Type Centers in Potassium and Rubidium Iodide Crystals

Abstract

Photoluminescence of V-type centers has been studied for KI and RbI crystals containing excess of iodine. Colored crystals were irradiated previously with V₃ light at LNT to convert primary V centers into other V-type centers which induced absorption bands in the uv and the visible regions. It was found that when the samples are excited in one of absorption bands at LNT for KI and at 68 K for RbI, they exhibit two emission bands at 1540 and 1690 nm in KI; 1500 and 1630 nm in RbI, respectively. The excitation spectra consist of three bands at 350, 440 and 800 nm in KI; at 350, 445 and 800 nm in RbI, respectively. Separations of the two emission bands increase with increasing of temperature. In both iodides the luminescence is ascribed to transitions in the same type of trapped hole centers containing iodine atoms.