Evolution of the optical properties of III-V nitride alloys: Direct band-to-band transitions in GaNyP1-y (0≤y≤0.029)

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

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Abstract

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 Γ point (E0 and E′0), and along the Λ direction (E1 and E′1) in GaNyP1-y (0≤y≤0.029) using spectroscopic ellipsometry. We detect two additional transitions, labeled here E21 and E22, which cannot be assigned unambiguously. We observe a strong blueshift of the direct transition energies E0 and E1 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 E′0, E21, E22, and E′1 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)
Article number245207
Pages (from-to)2452071-2452076
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume65
Issue number24
StatePublished - Jun 15 2002

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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