Tunable Synthesis of SiC/SiO(2) Heterojunctions via Temperature Modulation

A large-scale production of necklace-like SiC/SiO(2) heterojunctions was obtained by a molten salt-mediated chemical vapor reaction technique without a metallic catalyst or flowing gas. The effect of the firing temperature on the evolution of the phase composition, microstructure, and morphology of the SiC/SiO(2) heterojunctions was studied. The necklace-like SiC/SiO(2) nanochains, several centimeters in length, were composed of SiC/SiO(2) core-shell chains and amorphous SiO(2) beans. The morphologies of the as-prepared products could be tuned by adjusting the firing temperature. In fact, the diameter of the SiO(2) beans decreased, whereas the diameter of the SiC fibers and the thickness of the SiO(2) shell increased as the temperature increased. The growth mechanism of the necklace-like structure was controlled by the vapor-solid growth procedure and the modulation procedure via a molten salt-mediated chemical vapor reaction process.