Epitaxial CdF2 layers and CdF2-CaF2 superlattices have been grown on S
i(111) substrates by means of molecular beam epitaxy. Double crystal X
-ray diffractometry showed their high structural perfection. X-ray pho
toelectron spectroscopy revealed that CdF2 conduction band lies below
that of Si by 0.8 eV. It was found from the cathodoluminescence measur
ements that Eu3+ ions in epitaxial layer occupy C-4v sites.