针尖状SiC纳米线的合成与机理分析

Synthesis and Growth Mechanism of Needle-shaped Silicon Carbide Nanowires

采用热蒸发硅的方法,于1650℃反应不同的时间,在聚丙烯腈(PAN)碳纤维上原位生长碳化硅纳米线。通过X射线衍射,场发射扫描电镜及透射电子显微镜分析和观察,发现制得的产物为β-SiC单晶纳米线,具有明显的针尖状头部,且呈放射状生长在碳纤维上,形成试管刷状阵列。基于在反应不同阶段所得到产物的不同形貌,结合对制备条件和制备原料的分析,提出不同于传统VLS机理的VL’S机理。

SiC nanowires were prepared by thermal evaporation of Si onto PAN-carbon fiber at 1650℃ for deferent time. The XRD analysis, FESEM and TEM observation reveal that the as-grown products are single crystal β-SiC nanowires with needle shape radially standing on the carbon fiber surface. The SiC nanowires composed a tube-brush shaped array around the carbon fibers. A VL＇S growth mechanism, which is different from the conventional VLS mechanism, for the SiC nanowires growth is discussed.