A survey of conduction and valence band edges in SiC

A brief summary gives the current status of our understanding of the structure of the conduction band edges of BC. The latest values for the effective masses as derived from theory and verified by experiment are given. Absorption data for higher conduction bands in 4H and 6H SiC and a theoretical interpretation in terms of first principles band calculations are reviewed. Ballistic-electron emission microscopy (BEEM) experiments sensing the bottom and higher conduction bands in 4H, 6H and 15R SiC are described and compared with theory. The current picture for the shape of the edge of the valence band near the Gamma point in the Brillouin zone is given. New experimental data for the spin-orbit and crystal field splittings in 6H SiC are in good agreement with one set of recent calculated values but do not agree as well with two other calculations. However, the linear relationship for the crystal held splitting, Delta(CF) with hexagonality still remains to be experimentally verified by measuring values of the crystal held splitting in 4H and 15R SiC.