自蔓延高温合成氮化铝晶须形态和生长机理研究(1)

Morphologies and Growth Mechanisms of Aluminum Nitride Whiskers by SHS Method(1)

采用自蔓延高温合成技术（ＳＨＳ） ，在高压氮气中成功地合成了氮化铝晶须，并对它的显微结构进行了研究。研究结果表明，由于制备时的生长条件极不稳定，出现不同形态的晶须形貌，除了细长均匀的氮化铝晶须外，还出现了各种其它不规则形状的产物。过饱和度的不同，产生了枝蔓晶结构。按照ＶＳ生长方式，在均衡生长条件下，生长为本征结构的氮化铝晶须。晶须顶端的杂质小液滴，为ＶＬＳ生长方式创造了条件。通过光学显微镜观察，合成出的氮化铝晶须是透明的。

AlN whiskers were fabricated under high nitrogen pressure by using SHS (Self propagation High temperature Sythesis) method.The microstructures of AlN whiskers were studied.Due to unsteady of growth conditions,different morphologies were observed in the whiskers,except thin,long,and even AlN whiskers,several products with irregular shapes occur.The difference of supersaturation causes AlN whiskers with dendritic crystal structure.In equilibrium condition,AlN whiskers with hexagonal structure,the structure of AlN,were grown via VS mechanism.The impurity droplets on the top of whiskers create the condition for VLS mechanism.AlN whiskers synthesized are optically transparent or translucent under optical microscope.