Some Aspects of the Structural, Mechanical, and Electronic Properties of Sic

issues. These include the material employed in the reactor walls, the cladding material for the fissile nuclear fuel, and the material used for retaining the fission products. In addition to long term resistance to irradiation, the materials used in a nuclear reactor must have excellent mechanical and corrosion properties in order to tolerate the thermal shocks as well as the high temperature and severe corrosive environments that they will encounter during operation. One of the materials that has long been considered for this purpose is SiC, a material that is used both for its ceramic characteristics, as well as its wide bandgap semiconducting properties. In this paper, after reviewing the structure of various SiC polytypes, we discuss recent results on the mechanical and fracture properties of single polytype, single crystal 4H-SiC that has recently become available. We also discuss one of the many cases where lattice defects in the crystal affect the electronic properties of this high-temperature semiconductor.