Characterization of SiC nanowires prepared onC/C composite without catalyst by CVD
(State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: SiC nanowires were prepared on C/C composite surface without catalyst by chemical vapor deposition (CVD) using CH3SiCl3 as precursor. SEM images of the CVD-product reveal that some long nanowires have grown to tens of micrometers with some gathered as a ball. Some short nanowires agglomerate like chestnut shell with many thorns accompanied by some deposited nano-particles. XRD, Raman-spectrum and FTIR patterns indicate that the product is a typical β-SiC. TEM images show that the nanowires have a wide diameter range from 10 to 100 nm, and some thin nanowires are bonded to the thick one by amorphous CVD-SiC. A SiC branch generates from an amorphous section of a thick one with an angle of 70° between them, which is consistent with the [111] axis stacking angle of the crystal. SAED and fast Fourier transform (FFT) patterns reveal that the nanowires can grow along with different axes, and the bamboo-nodes section is full of stacking faults and twin crystal. The twisted SiC lattice planes reveal that the screw dislocation growth is the main mechanism for the CVD-SiC nanowires.
Key words: SiC nanowires; C/C composite; chemical vapor deposition; growth mechanism; characterization