Münster 1999 – scientific programme

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HL: Halbleiterphysik

HL 12: Poster I

HL 12.85: Poster

Monday, March 22, 1999, 14:00–18:00, Z

Optical constants of nearly-disordered Al_xGa_1−xInP (0<x<1) — •Gunnar Leibiger¹, Mathias Schubert¹, Bernd Rheinländer¹, Ines Pietzonka², and Volker Gottschalch² — ¹Fakultät für Physik und Geowissenschaften, Halbleiterphysik, Linnestraße 5, D-04103 Leipzig — ²Fakultät für Chemie und Mineralogie, Halbleiterchemie, Linnestraße 3, D-04103 Leipzig

We report the determination of the complex dielectric function

and critical point energies of nearly-disordered Al_xGa_1−xInP

over the full range of composition x, and for photon energies

from 0.75 eV to 5 eV by variable angle of incidence spectroscopic

ellipsometry (VASE). The MOVPE-grown samples were analyzed by

TEM and generalized VASE to confirm their almost disordered

state. We use the one-electron interband-transition model with

Gaussian-broadening and excitonic contributions for succesful

parameterization of the dielectric function near the E₀-,

E₁-, and E₂-type critical point transitions. We

obtain excellent agreement with our measured data, especially

within the near-band-gap spectral range. Our results are

compared to previous reports from other authors.