Photoluminescence properties of SiC/SiO2 heterojunctions obtained by TiO2-assisted chemical vapor deposition

SiC/SiO2 heterojunctions have been synthesized at 1400 degrees C by chemical vapor deposition, using Si and phenolic resin powder as starting materials and TiO2 nanoparticles as catalyst. The morphology of the SiC/SiO2 heterojunctions consists of chain-bead shaped and core-shell chains, and the heterojunctions are up to several hundred microns in length, with diameters of 0.3-1 mu m in the chains and 2-8 mu m in the beads. A vapor-solid tip-growth mechanism for the formation of the heterojunctions is proposed. Photoluminescence spectra of SiC/SiO2 heterojunctions exhibit a significant blue-shift, which indicates that these materials are ideal for application in new optoelectronic devices. The TiO2 nanoparticles play a key role in promoting the formation and growth of the heterojunction nanochains as well as in enhancing their luminescence properties.