Relaxed Si1-yCy and Si-lattice-matched Si1-x-yGexCy alloys 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-yCy lies 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-yGexCy has a direct gap and the band gap is reduced by -3.9y eV from that in relaxed Si1-xGex. The free energy of Si1-x-yGexCy shows that the atoms are arranged at random, however, this arrangement does not affect the result for the band gap in the alloy.
|Number of pages||5|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2001|
ASJC Scopus subject areas
- Condensed Matter Physics