Electronic Band Structure of SiC Polytypes: A Discussion of Theory and Experiment

After a brief discussion of the origin of polytypes and a few general remarks on the relationship between polytypism and properties of SiC, we focus on a comparative study of their electronic band structures. We first explain how the different band structures can be put on the same footing by examining Brillouin zone folding effects. Then we discuss the dependency of some of the important eigenvalues on hexagonality. Next, we discuss some of the available spectroscopic information on the band structures. Finally, we examine some of the details near the gaps in further detail such as the location of the conduction-band minima, the effective masses and the crystal field splittings and masses of the upper valence bands. Open questions and areas where experimental verification is needed are pointed out.