We apply the (Formula presented) tight-binding model to study the electronic energy band structure of the cubic (Formula presented) alloy. First by the effective medium approximation where local atomic fine structures are averaged out, it is obtained that the energy band gaps of both relaxed and strained (Formula presented) alloys increase with increasing C content. The effect of the local Si-C atomic bond structure on the energy band is studied in the real space in order to include the actual broken translational symmetry in the (Formula presented) alloy. The electronic local densities of states are investigated and the following is concluded: (a) When Si-C bond length in the alloy assumes the crystal SiC one (strained alloy), an electronic state at the C atom and its surrounding Si atoms is induced in the energy band gap of crystal Si. The valence band edge is slightly lifted. The results indicate a type I energy band alignment for strained (Formula presented) quantum well. (b) When the Si-C bonds assume the Si-Si bond length of the crystal Si (relaxed alloy), the electronic states are not much modified.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1998|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics