Thermochemical vapor growth of beta-SiC nanospheres

SiC nanospheres have been grown successfully via thermochemical decomposition of tetramethylsilane as a single molecular precursor for Si and C free from halogen. The growth temperature was varied from 700 to 900 degrees C in presence of H2, Ar, and N2 as process gases. XRD analyses showed that the synthesized nanoparticles under various experimental conditions are mainly composed of SiC phase and have broad and low intensity diffraction peaks implying its tiny size characteristics. SEM and TEM images confirmed the formation of SiC nanospheres in the size range of 100-250 nm. Denser cluster formation was observed for the sample deposited in presence of N2 gas. FTIR spectrum showed that the stretching vibration band corresponding to Si-O bond was observed whereas that corresponding to Si-H bond disappeared for the sample deposited in presence of N2 gas. This indicated the formation of oxygen-containing SiC layer on the nanospheres surface. Slight positive and negative weight changes (1.5-7 wt.%) were observed upon heating of SiC nanospheres in dynamic nitrogen atmosphere upto 500 degrees C. This slight changes might be due to the removal of residual un-disproportionated materials and/or formation of N2-dopped SiC nanospheres.