Band structure of large-sized SiC nanocomposites

The and energy structure of large-sized SiC nanocomposites (above 10 nm) was calculated. We used self-consistent norm-conserving pseudopotential method and molecular dynamics simulations of the nanocrystallite interface geometry. Essential changes of the band energy parameters versus the nanocrystallite sizes have been observed. Molecular dynamics structural simulations allowed to find a relation between the degree of hexagonality H (relative presence of hexagonal-like phase) and the sizes. Evaluated size-dependent behavior of the energy gap is compared with the experimentally obtained results. Theoretical data have been compared also with experimental optical spectroscopy and X-ray diffraction measurements. The experimental data are in a good agreement with theoretically calculated data. (C) 2000 Elsevier Science B.V. All rights reserved.