Specific Features of the Defect Formation in LiF Crystals as a Result of Implantation of Li⁺ and F⁺ Ions

Abstract

The results of an investigation of the mechanical, electrical, and optical properties in the near‐surface layer of LiF crystals irradiated with Li+ and F+ ions (energy 80 keV, fluence up to 1017 cm−2) are presented. The hardening in the layer, the thickness of which is by an order of magnitude larger than the ion penetration depth, as well as a significant difference in conductivity change are revealed. The conductivity change is explained in the case of F+ implantation by a combination of cation vacancies with hole centers and in the case of Li+ implantation by the appearance of an electron component in conductivity with an activation energy of 0.36 eV. By optical measurements the temperature change of the position and half‐width of the colloidal absorption band is observed. The latter one is connected with electron‐phonon interaction in Li colloidal particles. It is found also that the colloidal band can be separated into three elemental bands, the shape of which is nearly Gaussian in wavelength coordinates due to the statistical particle‐size distribution.