Growth of bulk GaN with low dislocation density by the ammonothermal method using polycrystalline GaN nutrient

A bulk GaN crystal with improved structural quality was grown via ammonthermal growth with polycrystalline GaN nutrient and a sodium amide mineralize-. The threading dislocation density estimated by plan-view transmission electron microscopy observations was less than 1 X 10(6) cm(-2) for the Ga-face and 1 X 10(7)cm(-2) for the N-face. There was no dislocation generation observed at the interface on the Ga-face although a few defects were generated at the interface on the N-face. The chemical etching revealed macroscopic grains on the N-face.