Fabrication of centimeter-scale well-aligned SiC/SiO ₂ core-shell nanowires by interlaminar vapor-diffusion reaction method

Centimeter-scale well-aligned SiC/SiO ₂ core-shell nanowires were fabricated by a novel interlaminar vapor-diffusion reaction method in a double-channel quartz tube. The synthesized nanowires grew in a uniform direction perpendicular to a porous graphite substrate and were parallel to one another. The core-shell nanowires are 10 millimeters long and consist of β-SiC crystalline core of with diameters of 30-60 nm wrapped with an amorphous silica layer of about 20 nm. The formation mechanism of the well-aligned nanostructure is probably ascribed to the downward vapor-solid growth process and gravity revulsive effect that plays an important role because of super high aspect ratio of the as-received nanowires.