Local Environment of Ce³⁺ Ions in CaS Prepared With or Without Flux

The effect of the preparation method on Ce³⁺ ion doping into crystals is examined. When is prepared in a gas flow without any flux, at least two different kinds of Ce³⁺ centers are introduced into the host. On the other hand, when alkali compounds are used as the flux during preparation, only one Ce³⁺ center is observed. This makes for differences in luminescence, excitation spectra, and temperature dependence of luminance between the two preparation methods. It was also found that , prepared with codopant ions, has shallower trap states with a lower concentration than it does without a codopant.