Excellent crystallinity of truly bulk ammonothermal GaN

In this paper we are presenting the excellent structural parameters of truly bulk gallium nitride crystals, which were grown by using the AMMONO-Bulk Method. In the crystals grown using this method a low dislocation density in the order of 5×103 cm−2 is readily attainable. At the same time the lattice of ammonothermally grown crystals is extremely uniform. Regardless of the crystal size, the radius of lattice curvature is higher than 100 m, whereas in the best crystals it is higher than 1000 m. Exceptional crystallinity is also evident in a very narrow X-ray (0 0 0 2) rocking curves, with FWHM values of about 17 arcsec as measured by a standard Panalytical X’pert high-resolution diffractometer.Such excellent structural parameters of AMMONO-GaN crystals show clearly that truly bulk GaN can be grown by using a scalable method, which can be employed in mass production. The authors are convinced that crystals produced using their method will make a breakthrough in the manufacturing of high-power GaN-based devices.