Relaxed Si1−yCyand Si-lattice-matched Si1−x−yGexCyalloys with low C concentrations of 1.6% and 3.1% have been studied from first principles. The bottom of the conduction bands in relaxed Si1−yCylies on the line Δ, as it does in Si. The band gap is linearly dependent on the C concentration and the reduction is as little as −0.9y eV On the other hand, Si-lattice-matched Si1−x−yGexCyhas a direct gap and the band gap is reduced by−3.9y eV from that in relaxed Si1−x−yGexThe free energy of Si1−x−yGexCyshows that the atoms are arranged at random, however, this arrangement does not affect the result for the band gap in the alloy.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2001 Apr 10|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics