Tunable optical gap at a fixed lattice constant in group-IV semiconductor alloys

V. R. D'Costa, Y. Y. Fang, J. Tolle, John Kouvetakis, Jose Menendez

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A direct absorption edge tunable between 0.8 and ∼1.4eV is demonstrated in strain-free ternary Ge1-x-ySixSny alloys epitaxially grown on Ge-buffered Si. This decoupling of electronic structure and lattice parameter-unprecedented in group-IV alloys-opens up new possibilities in silicon photonics, particularly in the field of photovoltaics. The compositional dependence of the direct band gap in Ge1-x-ySixSny exhibits a nonmonotonic behavior that is explained in terms of coexisting small and giant bowing parameters in the two-dimensional compositional space.

Original languageEnglish (US)
Article number107403
JournalPhysical Review Letters
Issue number10
StatePublished - Mar 9 2009


ASJC Scopus subject areas

  • Physics and Astronomy(all)

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