Optical phonons in hexagonal AlxInyGa1-x-yN (y ≈ 0.12)

A. Kasic, M. Schubert, J. Off, F. Scholz, S. Einfeldt, D. Hommel

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We report on first studies of the phonon mode properties of hexagonal AlxInyGa1-x-yN films. The 200-330 nm thick quaternary films (0 ≤ x ≤ 0.40, y ≈ 0.12), grown by MOCVD on 6H-SiC substrates, are pseudomorphically strained to the GaN buffer layers. We observe and differentiate the influence of strain and alloying on the frequency of the GaN-like E1(TO) phonon mode of AlxInyGa1-x-yN using infrared spectroscopic ellipsometry. Assuming the effective electron mass value of GaN, the free-electron concentrations are estimated from the A1-LO-phonon-plasmon coupled mode frequencies and increase by about two orders of magnitude in going from x = 0 to x = 0.40. We further obtain the composition dependence of the polarity for the AlN-like phonon mode with E1 symmetry. A possibly disorder-induced absorption band occurs above the GaN-like E1(TO) mode.

Original languageEnglish (US)
Pages (from-to)970-974
Number of pages5
JournalPhysica Status Solidi (B) Basic Research
Volume234
Issue number3
DOIs
StatePublished - Dec 1 2002

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Phonons
phonons
Spectroscopic ellipsometry
Electrons
Metallorganic chemical vapor deposition
Buffer layers
Alloying
Thick films
Absorption spectra
Infrared radiation
electron mass
Substrates
Chemical analysis
coupled modes
free electrons
alloying
ellipsometry
metalorganic chemical vapor deposition
polarity
buffers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Optical phonons in hexagonal AlxInyGa1-x-yN (y ≈ 0.12). / Kasic, A.; Schubert, M.; Off, J.; Scholz, F.; Einfeldt, S.; Hommel, D.

In: Physica Status Solidi (B) Basic Research, Vol. 234, No. 3, 01.12.2002, p. 970-974.

Research output: Contribution to journalArticle

Kasic, A. ; Schubert, M. ; Off, J. ; Scholz, F. ; Einfeldt, S. ; Hommel, D. / Optical phonons in hexagonal AlxInyGa1-x-yN (y ≈ 0.12). In: Physica Status Solidi (B) Basic Research. 2002 ; Vol. 234, No. 3. pp. 970-974.
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AU - Einfeldt, S.

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