Band structure of large-sized SiC nanocomposites

The and energy structure of large-sized SiC nanocomposites (above 10 nm) wa s calculated. We used self-consistent norm-conserving pseudopotential metho d and molecular dynamics simulations of the nanocrystallite interface geome try. Essential changes of the band energy parameters versus the nanocrystal lite sizes have been observed. Molecular dynamics structural simulations al lowed to find a relation between the degree of hexagonality H (relative pre sence of hexagonal-like phase) and the sizes. Evaluated size-dependent beha vior of the energy gap is compared with the experimentally obtained results . Theoretical data have been compared also with experimental optical spectr oscopy and X-ray diffraction measurements. The experimental data are in a g ood agreement with theoretically calculated data. (C) 2000 Elsevier Science B.V. All rights reserved.