Single crystal growth of Gallium Nitride by slow-cooling of its congruent melt under high pressure

Utsumi, Wataru; Saito, Hiroyuki; Kaneko, Hiroshi*; Kiriyama, Koji*; Aoki, Katsutoshi

We were successful in synthesizing single crystals of GaN (Gallium Nitride) by slow cooling of its congruent melt under high pressure. It was confiremed by in situ X-ray diffraction that applying high pressures above 6.0 GPa completely prevented the decomposition and allowed the congruent melt of GaN at 2220C. Using a cubic-anvil-type large volume high-pressure apparatus and GaN powder as a starting material, single crystal growth was performed by decreasing temperature from 2400C at 6.5 GPa. The X-ray rocking curve of the recovered sample showed very narrow line-width smaller than 30 arcsec, suggesting its low dislocation density.