Influence of annealing medium on photoluminescence and optical properties of ZnSe:Cr crystals

Modification of photoluminescence (PL) and optical properties of ZnSe:Cr crystals caused by annealing in medium of Zn or Se vapors are investigated. Possibility to modify the intensity of infrared (IR) impurity PL (∼1 µm and 2 µm) and optical absorption spectra by several orders of magnitude, reversibility of the observed modifications of crystal properties, influence of co-doping with Cr and Cl impurities on radiative and optical properties of ZnSe are discussed. Models that explain both disappearance of image centers responsible for the IR emission due to crystal enrichment with Zn and formation of Cr2Se3 precipitates against the background of crystal enrichment with Se are suggested. Complex PL bands in the IR and edge spectral ranges are analyzed for ZnSe:Cr crystals.