Synthesis And Characterization Of SiC Nanostructures

This thesis is focused on the synthesis of SiC powder via chemical vapordeposition(CVD) and direct current arc discharge, respectively.Cubic phase SiC nanoparticles with sizes of70nm were synthesized here through thedirection reaction between carbon nanotubes and silicon powder at high temperature, and therelated growth mechnism was discussed. The influences of carbon source, reactiontemperature and duration on morphologies of products were examined. The resultsimply that carbon nanotubes don’t provide one-dimensional templates for growth ofSiC products in our case. It is speculated that the frameworks of carbon nanotubeswere destroyed by melt Silicon at high temperature which leads to the formation ofSiC nanoparticles instead of nanowires or nanorods.Direct Current Arc Discharge technique was also employed to synthesize SiCpowder, and the morphologies of products synthesized with different reaction current werediscussed. Experiments showed that SiC powder synthesized with graphite powder isblock. This might because Si is more active, therefore, the SiC block were generatedfaster than the one-dimensional nanostructure. At last, SiC block were obtained.Gallium-doped silicon carbide were successfully fabricated through the Direct CurrentArc Discharge, optical properties of the as-synthesized samples were analyzed.Compared with the data of pure phase, the PL spectra of doped sample changed,however, the formation mechanism needs further study.