Influence of Eu and Gd impurities on crystal structure of ZnS monocrystals

Spectra of EPR, reflection and absorption of ZnS, ZnS:Eu, ZnS:Gd monocrystals grown from a melt have been studied. Their X-ray analysis is carried out. A decrease of the ratio of intensities of bands attributed to cubical and hexagonal parts of EPR spectrum of Mn2+ ions, shift and splitting of exiton lines in reflection spectra are observed in doped crystals, which points to the increase of hexagonal phase part in cubical crystals. It has been established it constitutes less than 10% in ZnS, and in crystals ZnS:Eu and Zn:Gd increases approximately up to 22 and 30% respectively