Cathodoluminescent efficiency of Y3Al5O12 and YAlO3 single crystals in dependence on Ce3+ and other dopants concentration

The content of Ce3+ ions in the investigated single crystals grown under reducing conditions is limited by a low value of the distribution coefficient. This distribution coefficient decreases sharply with increasing concentration of Ce3+ ions in melt. Cathodoluminescent efficiency rises with increasing Ce3+ concentration up to a certain state of saturation. At higher concentrations of Ce3+ ions emission from activator centres is dominant, while at lower concentrations defect centres play an important part. Iron acts as a strong quenching centre, especially in the YAlO3 lattice. Nd, Ir, Fe, Ti, Cr centres exhibit a high quenching effect, too. A trace amount of Mo enhances cathodoluminescent efficiency. (author)