Influence of the local microstructure on the macroscopic properties of Si 1-x-yGe xC y alloys

W. Windl, J. D. Kress, A. F. Voter, Jose Menendez, O. F. Sankey

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


We performed a theoretical study of the microscopic arrangement of the C atoms in Si 1×x-yGe xC y alloys using the Sankey local-orbital density-functional formalism. Our first-principles calculations show that in the dilute limit, the lattice constant in Si 1-yC y alloys decreases much more (by about 2/3) with concentration than predicted by Vegard's law. We show that this result is consistent with Raman and infrared experiments and with previous empirical calculations. As the C concentration increases, the interactions between the C atoms become important: Interstitial C becomes more abundant and increases the lattice constant, and the substitutional C atoms array under appropriate growth conditions. The effect of this ordering on the lattice constant is small, but it can be seen in the Raman spectra of layer-by-layer grown samples.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
Number of pages6
StatePublished - 1997
Externally publishedYes
EventProceedings of the 1997 MRS Spring Symposium - San Francisco, CA, USA
Duration: Apr 1 1997Apr 4 1997


OtherProceedings of the 1997 MRS Spring Symposium
CitySan Francisco, CA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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