Synthesis and Characterization of Rare Earth Nitride ScN and YN Microcrystalline

Rare earth nitride ScN and YN crystals were synthesized through direct nitridation of Sc and Y metals with nitrogen using plasma assisted direct current arc discharge method. This new method is fast, low cost and high yield for preparing rare earth metal nitrides. Structural and elemental characterization indicate that the as-synthesized ScN crystals are stoichiometric single crystalline and YN crystals are nonstoichiometric polycrystalline with random orientation single crystal particles. Considering XRD, EDS, HRTEM, and PL results of YN crystals, non-crystalline phase of metal Y is deduced to be formed in YN which contributes to the high contents of Y in EDS results. PL spectrum shows that the presence of large amounts of N vacancy in YN crystals. In addition, the microstructure formation mechanism of YN and ScN samples is analyzed. The difference between them is attributed to the high dissociation pressure of yttrium-group metal nitrides of limiting compositions as well as the high quench rate (10 3 K/s) that would result in the disordered arrangements of the clusters of Y atoms and then forming non-crystalline structure upon quenching.