Isotopic mass dependence of the lattice parameter in silicon determined by measurement of strain-induced splitting of impurity bound exciton transitions

A. Yang, H. J. Lian, M. L W Thewalt, M. Uemura, A. Sagara, Kohei M Itoh, E. E. Haller, J. W. Ager, S. A. Lyon

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The strain-induced splitting of the impurity bound exciton (BE) transitions in epitaxial layers of isotopically enriched 28Si grown on silicon substrates of natural isotopic composition has been studied using high-resolution photoluminescence (PL) spectroscopy. The slight difference in lattice parameter between the 28Si epitaxial layer and the natural silicon substrate induces a biaxial strain in the epitaxial layer, which can be detected with remarkable sensitivity using low-temperature PL. Measurement of the splitting of the BE transitions in these epitaxial layers of 28Si provides us a method for determining the isotopic mass dependence of the lattice parameter in silicon with unprecedented precision. The level of precision achieved is attributed to the fact that the BE no-phonon transitions in isotopically enriched silicon are much sharper than in natural silicon. We find that scaled to an isotopic mass difference (ΔM) of 1 amu, the relative difference in lattice parameter (|Δa/a|) for silicon is 3.3×10-5.

Original languageEnglish
Pages (from-to)54-56
Number of pages3
JournalPhysica B: Condensed Matter
Issue number1
Publication statusPublished - 2006 Apr 1



  • Exciton
  • Isotopic
  • Photoluminescence
  • Silicon

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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