Synthesis of high-crystallinity cubic-GaN nanoparticles using the Na flux method—A proposed new usage for a belt-type high-pressure apparatus

We developed a gas-sealing technique by adopting a metal capsule in a belt-type high-pressure apparatus, which enabled a supply of high-pressure nitrogen gas of several hundred MPa.With employing the sealing technique, cubic-GaN (c-GaN) nanoparticles were successfully synthesized using the Na flux method under nitrogen pressure above 100 MPa. A high cubic/hexagonal ratio of more than 20 can be achieved by optimizing the synthesis conditions.An attempt was made to functionalize c-GaN by doping Eu element as a luminous origin. Cathodoluminescence and XANES study revealed that Eu can be doped into the c-GaN particles, causing them to take on the state of Eu3+.