Electronic properties of SiC polytypes: Charge neutrality level and interfacial barrier heights

The position of the intrinsic charge neutrality level (CNL) in a number of silicon carbide polytypes has been determined based on the calculations within density functional theory and quasiparticle G0W0 approximation. We have considered eight polytype structures of SiC, including the simplest cubic one as well as various hexagonal and rhombohedral polymorphs. The theoretical band gaps calculated within G0W0 are in excellent agreement with experiment. The CNL energy positions in SiC polytypes are found to be very close to each other with average value of 1.76 eV above the valence band maximum. On the basis of the performed CNL computations, the electronic properties of irradiated silicon carbide and the energy diagrams of the metal/SiC interfaces and some heteropolytype junctions based on SiC have been analyzed. We also give estimations of the electron affinity in SiC polytypes as a function of their hexagonality.