Growth of bulk GaN single crystals by flux method

The progresses on the growth of bulk GaN crystals by the flux method in our research group are reported in this review. The research work is mainly focused on the ternary system Li-Ga-N. The phase relations are constructed by the calculation of phase diagram (CALPHAD) technique based on the optimized thermodynamic data of the corresponding binary systems Li-N, Li-Ga and Ga-N. There exists a two-phase region of liquid+GaN at above 750 °C. The well-crystallized, transparent GaN plate-like crystals up to a size of 4 mm can be grown from the Li-Ga-N system under pressures of 1-2 N2 atmospheres. The yield and quality of the GaN crystals depend on the composition of the starting materials, the growth temperature, the cooling rate, and the position of Li3N in the crucible. Efforts are still needed to further enlarge the size of crystals.