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

Abstract

We grew bulk GaN single crystals by solvent-thermal method. GaN single crystals were synthesized at 600-800 °C and 6-8 MPa of N 2 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.

Bulk GaN single crystal growth and characterization using various alkali metal flux

“…An N 2 pressure of 8 MPa was used and the flux ratio (g flux ) was varied in the range 0.30-0.67, where g flux is the mole fraction of flux/(Ga+flux) in the starting solution. The GaN single crystals were grown using the 4 different growth conditions shown in Table 1, and the results were compared with those obtained under other conditions used in previous studies [7,8].…”

“…Therefore, in this study, we attempted to grow bulk GaN single crystal by the solvent-thermal method. When using a flux, the solvent-thermal method of growing bulk GaN single crystal requires a lower temperature ($800 1C) and pressure ($100 atm) than when growing them directly from high-temperature melts [7]. Bulk GaN single crystals were grown using various alkali metals as a flux.…”