Low-pressure acidic ammonothermal growth of 2-inch-diameter nearly bowing-free bulk GaN crystals

Seeded growth of 2-inch-diameter GaN crystals via low-pressure (similar to 100 MPa) acidic ammonothermal method is demonstrated. Nearly bowing- and mosaic-free GaN crystals exhibiting full-width at half-maximum values for the 0002 X-ray rocking curves below 20 arcsec were achieved on high lattice coherency c-plane SCAAT (TM) seeds with gross dislocation densities in the order of 10(4) cm(-2). The photoluminescence spectra of the grown crystals exhibited a predominant near-band-edge emission at 295 K, of which intensity was one order of magnitude higher than the characteristic deep-state emission bands. A nearly bowing-free 60 mm x 60 mm c-plane GaN crystal was eventually obtained. (c) 2022 The Japan Society of Applied Physics

Automated summary

This study demonstrates the seeded growth of 2-inch-diameter GaN crystals via low-pressure acidic ammonothermal method. The grown crystals exhibit high lattice coherency and nearly bowing- and mosaic-free features, with superior photoluminescence properties. A large-size, nearly bowing-free GaN crystal was successfully obtained.