Single crystals of of typical size were grown inside a sealed silica tube with and without excess of precursor . The process is reproducible for high growth temperatures at which the use of an alumina crucible is necessary. For lower growth temperatures the as-prepared crystals are underdoped with . An optimal is achieved by post-annealing the crystals in flowing oxygen at . Crystals grown at higher temperatures show an increase of the c-axis length after oxygen annealing, indicating they are overdoped.