Synthesis of coaxial nanowires of silicon nitride sheathed with silicon and silicon oxide

Coaxial nanowires, with about 45 nm in diameter and about 15 μm in length, have been synthesized by reaction of silicon dioxide nanoparticles with active carbon at 1450°C in flowing nitrogen atmosphere. Their structures consist of an α-phase silicon nitride core, an amorphous silicon and a silicon dioxide outer shell, similar to those of coaxial nanocables. The formation mechanism of the coaxial nanowires is discussed.