Large scale synthesis and photoluminescence properties of necklace-like SiC/SiOx heterojunctions via a molten salt mediated vapor reaction technique

Necklace-like SiC/SiOx heterojunctions were synthesized by a simplified vapor reaction technique using silicon powders as raw material without metallic catalyst or flowing gas at 1200 °C. Phase composition, morphology and microstructural characteristics of as-achieved products were characterized. The as-synthesized SiC/SiOx heterojunctions, up to millimeters in length, are composed of SiC/SiO2 core-shell chains with diameters of 0.3-1 µm and amorphous SiO2 beans with diameters of 2-5 µm. The growth mechanism of the as-synthesized SiC/SiO2 core-shell chains is most likely controlled by vapor-solid mechanism. The formation of SiO2 beans can be mainly attributed to the Rayleigh instability and surface tension. The photoluminescence spectra of the as-received products exhibit a significant violet-blue emission, making a potential application in violet-blue emitting devices.