The luminescence of ZnS and ZnSe doped with rare-earth ions is an interested field

[1-6]

.The reason for this is that

on one hand

the interaction between rare-earth ions and crystal lattice can be understanded by studying the luminescence of rare-earth ions in ZnS and ZnSe crystals

on the other hand

ZnS and ZnSe doped with rare-earth ions are potentially effective materials for colour display.Using ion implantation technique

ZnS and ZnSe diodes have been fabricated and electroluminescence of rare-earth ions have been observed on reverse bias

[2

3]

. One problem is that the efficiency of these diodes is not so high.