FLUORIDE LAYERS AND SUPERLATTICES GROWN BY MBE ON SI(111) - DYNAMIC RHEED AND SM2+ PHOTOLUMINESCENCE STUDIES

The oscillations of reflection high-energy electron diffraction intensity during CaF2 and SrF2 epitaxial growth on the (111) surface of silicon and the fluorides have been investigated. From these studies the critical thickness of the fluoride pseudomorphic growth mode was measured for different growth conditions. These data allowed us to grow strongly strained coherent fluoride layers and superlattices. Studies of Sm2+ ion photoluminescence in these fluoride structures at liquid-helium temperature have been shown to be useful for characterization of the crystalline quality of the films and for the measurement of elastic strain. High quantum yield of the luminescence enabled us to explore doped layers as thin as several monolayers.