Effect of Annealing in Chlorine Gas on Photoluminescence of X-Rayed KCl and a Hole-Trapped Center

Abstract

Luminescence was induced by F-light illumination on KCl crystals which were subjected annealing in chlorine gas at an elevated temperature and subsequent X-irradiation at room temperature. The emission was evident above 150 K, and its emission spectra exhibited peak around 2.7 eV. The luminescence was ascribed to recombination of photoelectrons from F centers with hole-trapped centers which were created in crystals by diffusion of chlorine molecules during the chlorine-treatment. The hole-trapped center has a character that it is destroyed by X-rays.