Electronic structure of Si1-yCy and Si1-x-yGexCy alloys with low C concentrations

M. Ohfuti, Y. Sugiyama, Yuji Awano, N. Yokoyama

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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.

Original languageEnglish
Article number195202
Pages (from-to)1952021-1952025
Number of pages5
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number19
Publication statusPublished - 2001
Externally publishedYes


ASJC Scopus subject areas

  • Condensed Matter Physics

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