Effect of annealing on the luminescence of $p$-CuI crystals

The photoluminescence spectra of CuI samples containing different numbers of intrinsic defects are studied at the temperature 80 K. The samples were excited with continuous-wave (cw) and pulse optical excitation. Emission peaks related to bound and free excitons, and to the recombination of electrons at shallow and deep crystal-lattice defect levels are observed. It is found that CuI crystals subjected to high-temperature annealing contain hexagonal phase inclusions.