Biruza

Congruent melting of GaN takes place at a pressure of 60000 atm of nitrogen and 2200 ? C, which technically prevents the introduction of the method of growing GaN from its own melt. However, gallium nitride may reversibly dissolved in a suitable melt. The value of solubility is crucial for the formation of GaN. Since 1997, Cornell University (United States) began to grow gallium nitride in the reaction of nitrogen (30-50 atm) with a solution of Na-Ga (750-850 ? C), which continued in Japan.Solubility of GaN in liquid sodium at 750-850 ? C is less than 0.1%. Dilution of the melt components, forming a low-melting ionic nitrides (eg, Li), and simultaneously formed with gallium nitride on fusible double nitrides (Li3GaN2, etc.) you can dramatically increase the solubility of GaN in the melt. As a limiting case of GaN can be considered a solution in the melt Li3N-Li3GaN2 (without the involvement of volatile sodium).The difficulty in the implementation of the method is not only to relatively high temperatures and pressures (10-100 atm of nitrogen and 800-900 ? C) The main obstacle - the choice of material for the container melt Aggressive additives (Li, Li3N), intensifying the process of growth, not only the dissolved gallium nitride, and dissolved (corrosive), the majority of other materials: corundum, graphite, boron nitride, platinum, etc There is a need to search for new, more resistant materials.