Single crystals were grown by using a high-pressure high-temperature method and were investigated by means of X-ray diffractometry and projection topography. Grown-in extended defects such as low-angle grain boundaries and straight dislocations, in directions related to the growing lattice planes, were observed for the first time. A sub-grain boundary divided the crystal into 2 misoriented parts.

Extended Defects in GaN Single Crystals. M.Lefeld-Sosnowska, I.Frymark: Journal of Physics D, 2001, 34[SA], 148-50