Growth of GaN single crystals by Ca3N2 flux

This paper reports recent progress on GaN single crystal growth by Ca3N2 flux. The isothermal phase diagrams of the Ca–Ga–N system were predicted from the corresponding binary systems by CALPHAD. Well-crystallized GaN crystals up to 1.5 mm were grown from the Ca–Ga–N system at 900 °C under 0.2 MPa N2 pressure. It was found that the crystal size depended on the molar ratio of starting materials, the temperature and the duration of growth. A growth mechanism involving two-step reactions is proposed.