Evolution of the optical properties of III-V nitride alloys: Direct band-to-band transitions in (formula presented) (formula presented)

Gunnar Leibiger, Volker Gottschalch, Mathias Schubert, G. Benndorf, R. Schwabe

Research output: Contribution to journalArticle

4 Scopus citations


Incorporation of nitrogen into III-V semiconductor compound materials dramatically alters their electronic properties. We report on the experimental observation of the evolution of the direct transition energies at the (formula presented) point (formula presented) and (formula presented) and along the (formula presented) direction (formula presented) and (formula presented) in (formula presented) (formula presented) using spectroscopic ellipsometry. We detect two additional transitions, labeled here (formula presented) and (formula presented) which cannot be assigned unambiguously. We observe a strong blueshift of the direct transition energies (formula presented) and (formula presented) with increasing nitrogen incorporation, in contrast to the well-known downshift of the conduction-band edge, which we also obtain for our samples using transmission and photoluminescence measurements. The critical-point transition energies (formula presented) (formula presented) (formula presented) and (formula presented) do not significantly shift with increasing nitrogen concentration. Our observations can be well understood within the model of III-nitride alloy formation proposed recently by Kent and Zunger.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number24
StatePublished - Jan 1 2002


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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