Distribution of luminescent centers in electroluminescent SrS : Ce films prepared by post-annealing in H2S

SrS:Ce films were investigated by secondary ion mass spectrometry (SIMS) in order to examine the luminescent center distribution in the phosphor befor e and after annealing. Cerium was accumulated near the interfaces between t he phosphor and insulating layers, and this accumulation was most extensive in the phosphor annealed in H2S. The Ce accumulation is found to shift the electroluminescent (EL) emission spectra to a longer wavelength. It is als o found that crystallinity improvement of the SrS phosphor by annealing in H2S causes Ce accumulation and the presence of oxygen enhances the Ce accum ulation. (C) 2000 Published by Elsevier Science B.V. All rights reserved.