Spatial-OH impurity distribution in gallium phosphate crystals

Piezoelectric properties of quartz and quartz-like materials are strongly r elated to the impurity content in the crystals and, more especially, to the ir hydroxyl group (-OH) content. This work has been devoted to the determin ation of the spatial distribution of this impurity in as-grown crystals of gallium phosphate, GaPO4. The investigation was undertaken by infrared spec troscopy from eight samples with different growth conditions and completed by thermally stimulated current/relaxation map analysis techniques. The res ults allow the best growth parameters to be defined, leading to crystals wi th the lowest -OH impurity content. (C) 1998 Kluwer Academic Publishers.