Far-infrared dielectric function and phonon modes of spontaneously ordered (AlxGa1-x)0.52In0.48P

Tino Hofmann, Mathias Schubert, Volker Gottschalch

Research output: Contribution to journalConference article

2 Scopus citations

Abstract

We present a far-infrared (fir) spectroscopic ellipsometry study of the phonon properties of partially CuPtB-ordered (AlxGa 1-x)0.52In0.48P with x=0, 0.32, 0.7 and 1.0, and degrees of ordering η from 0 to 0.63, as obtained by generalized ellipsometry measurement of the near-band-gap order birefringence. An anharmonic oscillator approach is used to model the ordinary and extraordinary dielectric functions and determine the infrared-active longitudinal and transverse phonon modes of the thin-film samples. Besides the isotropic GaP-, InP- and AlP-like phonon modes, we observe alloy-induced modes with low polarity. The phonon modes of highly ordered (AlxGa1-x)0.52In 0.48P with η~0.6 are compared to phonon modes observed in the highly disordered quaternary solid solution. We propose measurement of the fir dielectric anisotropy as a sensitive indicator for existence of sublattice ordering in multicomponent group-III-group-V semiconductor alloys.

Original languageEnglish (US)
Pages (from-to)601-604
Number of pages4
JournalThin Solid Films
Volume455-456
DOIs
Publication statusPublished - May 1 2004
EventThe 3rd International Conference on Spectroscopic Ellipsometry - Vienna, Austria
Duration: Jul 6 2003Jul 11 2003

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Keywords

  • AlGaInP
  • CuPt-ordering
  • Far-infrared ellipsometry
  • Phonon modes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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