热蒸发法碳化硅纳米晶须阵列的合成与表征

在1600℃不同真空度下, 采用热蒸发硅的方法, 在石墨基板和聚丙烯腈(PAN)炭纤维两种碳源基体原位生长具有一定取向的碳化硅纳米晶须——垂直于石墨片表面森林状和试管刷状碳化硅纳米晶须阵列。通过X射线衍射及场发射扫描电镜, 发现晶须为3C-SiC, 直径约100nm, 长度约50μm。炭纤维表面的产物顶端多为针尖状, 而石墨片表面的产物多为六方棱柱状。因其纳米尺寸效应, 在380nm波长的光激发下, 所制晶须在波长为468nm 附近出现光致发光峰。透射电镜、 多点衍射电子衍射图表明, 所制得的3C-SiC晶须为单晶, 其生长方向为3C-SiC的[111]方向。基于反应过程中硅熔体与碳源分离的事实, 讨论了3C-SiC晶须阵列生长的气固反应机理。 

Synthesis and characterization of silicon carbide whisker arrays prepared by thermal evaporation method

SiC whiskers arrays were prepared by thermal evaporation of Si onto two carbon templates: graphite plate and PAN-carbon fiber at 1600℃ in different levels of vacuum. The XRD analyses and FESEM observations reveal that the products are 3C-SiC whisker arrays: whisker forests standing on the graphite plate and tube brush shaped whisker arrays around the carbon fibers, respectively. The dimensions of the whiskers grown on the two templates are about 100nm in diameter and 50μm in length. Due to the quantum confinement effect of nano-materials, a photoluminescence peak locating around 468nm is observed under 380nm excitation at room temperature. The multi-place selected area electron diffraction (SAED) demonstrates that the SiC whiskers are single crystals, growing in [111] direction. Based on the fact that the silicon melt and carbon templates were separated throughout the whole process, the vapor-solid reaction growth mechanism of the SiC whiskers is discussed.