On luminescence of ZnWO4-Ni crystals

The spectra of cathodoluminescence and photoluminescence and also the change in intensity of a light which has passed along the crystal radius were measured to investigate the effect of the nickel concentration on the output and the spectra of the luminescence of ZnWO4-Ni2+ single crystals. It was found that low concentrations of Ni (less than 7 x 10-3 mol.%) do not affect the spectra. A further increase in in concentration results in luminescence quenching. In the cathodoluminescence regime concentric with the growth axis of the crystal alternating dark and light rings are observed. The production of the rings is attributed to the nonuniform distribution of nickel ions in the crystal lattice of ZnWO4