Deposition of nanocrystalline cubic silicon carbide films using the hot-filament chemical-vapor-deposition method

Nanocrystalline cubic silicon carbide (3C–SiC) films embedded in an amorphous SiC matrix were fabricated by the hot-filament chemical-vapor-deposition technique using methane and silane as reactance gases. High-resolution transmission electron micrographs clearly showed that these films contain naoncrystallites, with an average dimension of about 7 nm, embedded within an amorphous matrix. X-ray photoelectron spectroscopy, x-ray diffraction, infrared absorption, and Raman scattering studies revealed the nanocrystallites as having the structure of that of 3C–SiC. In contrast to 3C–SiC, where no photoluminescence could be observed at room temperature, strong visible emission with a peak energy of 2.2 eV could be seen from the nanocrystalline films at room temperature. The presence of nanocrystalline cubic SiC in these films is believed to result in a change in their energy-band structure, compared to that of 3C–SiC, which promotes radiative recombination of electron–hole pairs.