Growth of GaN Single Crystals Using Ca−Li3N Composite Flux

A Ca−Li 3 N composite flux was introduced to grow GaN single crystals from Ga melts. The obtained GaN crystals were colorless and up to 4 mm at 800 °C under N 2 pressure of about 2 atm. The effects of introducing the composite flux on the size distribution, morphologies, and yield of the GaN crystals were studied. It was found that the addition of Ca retarded the homogeneous nucleations to some extent and resulted in a more uniform size distribution of the GaN crystals in comparison with that grown using Li 3 N as flux only. The layered morphological feature on the GaN surface suggested that the layer growth mechanism was probably enhanced by the composite flux. The yield of the crystals was strongly dependent on the flux compositions. These results provided a possible new route for improving the growth of GaN crystals from melts in the future by optimizing the composite flux.