INVESTIGATION OF AS GROWN AND INDUCED STRUCTURAL DEFECTS IN SRLAXO4 (X=AL, GA) CRYSTALS

SrLaGaO4 and SrLaAlO4 substrates grown by the Czochralski method have no twins or subgrains however they show strong tendency to form point defects. The nature of these defects is not well understood yet. They may be associated with deviations from stoichiometry and/or oxygen ato ms located in the interstitial positions. Virtually all title crystals grown by the Czochralski method display various colours from light gr een to deeply red owing to Light absorption by point defects. Absorpti on centres appear to be very stable in time and resistant to usual the rmal treatment. UV excitation increases the density of defects and giv es rise to strong photoluminescence, otherwise too weak to be observed .