Electronic Structure of 3C Inclusions in 4H SiC

The band gap, the polarization, and the quantum well states for 3C inclusions in 4H SiC are studied in a systematic way with inclusions of 2-10 cubic layers in a supercell of 12 layers of 4H SiC. The polarization is strongly reduced by screening and correspondingly the effective band gap of the 3C quantum well in a 4H system is never smaller than that of pure 3C. To explain the observation of below 3C gap luminescence in such systems, an increase in exciton binding energy must be invoked.