Bulk GaN single crystal growth for substrate by solvent-thermal method

We grew bulk GaN single crystals by solvent-thermal method. GaN single crystals were synthesized at 600-800°C and 6-8 MPa of N₂ gas for 200 h. We used 99% pure Na as a flux. The mole fraction of Na / (Na+Ga) were 0.30-0.67. A pyramid GaN single crystal having a size of 1-3 mm grew on the bottom and wall of a sintered BN crucible. We confirmed wurtzite structure GaN which was grown single crystal through XRD pattern. The chemical composition was investigated by EPMA. Raman spectroscopy yielded narrow peaks representing only the modes allowed for the wurtzite structure.