稀土氮化物ScN、YN微晶的制备与表征

Synthesis and Characterization of Rare Earth Nitride ScN and YN Microcrystalline

利用直流电弧等离子体方法制备出稀土氮化物ScN、YN微晶,这是一种快速、低成本、高产量的新方法,可用来制备稀土金属氮化物。结构物性表征和能谱成分分析结果表明,所制备的ScN晶体为满足化学计量比的单晶,而YN晶体为非化学计量比的多晶,其中Y的含量高于N。综合XRD、EDS、HRTEM和PL结果分析表明,YN晶体主要由大量随机取向的单晶颗粒组成,单晶颗粒间分布着一些非晶的金属Y,光谱结果分析表明YN中存在大量的N空位。此外,对样品的微观结构形成机理进行了系统分析,由于Y族金属氮化物中有限组分较高的解离压力以及产物在生长过程中经历较高的淬火速率(103 K/s),导致YN解离而形成的Y金属团簇的无序排列,进而使其在冷却过程中形成了非晶结构。

Rare earth nitride SeN 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 SeN 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 SeN 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 （103 K/s） that would result in the disorderecl arrangements of the clusters of Y atoms and then forming non-crystalline structure upon quenching.