Gallium nitride synthesis using lithium metal as a nitrogen fixant

Micron-sized particles of gallium nitride were synthesized at temperatures as low as 300 degrees C under ammonia in anhydrous conditions. Two different syntheses were investigated: compound 1 was synthesized using a physical mixture of gallium and lithium under flowing ammonia; compound 2 was synthesized using a gallium/lithium alloy under flowing ammonia. These two methods relied on the presence of lithium metal acting as a nitrogen-fixing and transport agent for metallic gallium. Powder X-ray diffraction demonstrated the purity and crystalline nature of the resulting white gallium nitride; it was found to exhibit extraordinary crystallinity considering its formation conditions. Elemental analysis also determined the purity of 1 and 2 and showed an absence of the lithium impurity in the former, as contrasted with 0.23% Li in the latter. SEM demonstrated the particle sizes of 1 and 2 to be on the micron scale.