Crystal Structures and the Electronic Properties of Silicon-Rich Silicon Carbide by First Principle Calculations*

Silicon carbide has been used in a variety of applications such as solar cells material due to its high stability. Obtaining Silicon-rich silicon carbide materials are necessary to tune the band gap for efficient solar light absorptions. In addition, thermodynamically stable Si-rich SiC materials can be used in solar cell applications without requiring a pure grade silicon or pure grade silicon carbide materials which are very expensive materials. We have used density functional theory (DFT) calculations to examine different structures of silicon-rich silicon carbide to predict stable structures. Different configurations of silicon and carbon atoms in silicon-rich silicon carbide structures have been considered because the configurations play a significant role in getting stable results. The electronic structures have been studied, and the total energies have been calculated as well as the formation energies. These results will be presented. The results show that hexagonal-phases are more favorable structures than other silicon-rich silicon carbide structures due to their more covalent nature of bonding compared to the cubic counterpart.