Growth of SiC grains by gas evaporation method and relationship between optical properties and structure of SiC grains

In order to elucidate the correlations between structure of SiC grains and their spectra, three experimental methods of grain formation were used. By using an arc-discharge between silicon and carbon or SiC and carbon, grain formation conditions of α-SiC and β-SiC were elucidated. α-SiC grains were produced predominantly in an atmosphere containing an excess of silicon vapor. β-SiC grains were produced predominantly in an atmosphere containing an excess of carbon vapor. It has also been shown that mixed grains of silicon, α-SiC, β-SiC, carbon and C60 were produced by an advanced gas evaporation method (AGEM). Infrared (IR) spectra froth grains produced by AGEM showed absorption peaks at 11.3 and 12.6 μm. Peak values of IR spectra from grains produced by various methods are discussed in relation to the problem of lattice defects.