Distribution of aluminum and hydroxyl impurity-centers in synthetic quartz grown from cylindrical seeds

This study investigates the distribution of Al and OH defects in synthetic quartz grown from cylindrical seeds parallel to X, Y and Z crystallographic axes. Prismatic habit crystals were grown with m-, R-, r- and x- faces. The growth sectors were identified by radiation-induced coloration and their morphologies were characterized by X-ray topography. Optical and infrared spectroscopies were adopted to evaluate the occurrence of Al-hole, Al-OH and as-grown OH centers. It was found that the relative content of Al-hole and Al-OH centers were dependent on the growth sector and the orientation of the seed crystal. The ratio of Al-hole to Al-OH centers between +X- and -X-sectors grown from the Z-axis seed-crystal is opposite to that found in cylindrical Y-axis and standard Y-bar synthetic quartz crystals. The incorporation of Al-Li centers was responsible for the intense lattice strains observed in r-growth sectors appearing around the X-axis.