Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 12: Poster I

HL 12.50: Poster

Montag, 8. März 2004, 16:30–19:00, Poster A

Strong increase of the electron effective mass in GaAs incorporating boron and indium — •Tino Hofmann¹, Claas von Middendorff¹, Gunnar Leibiger², Volker Gottschalch², and Mathias Schubert¹ — ¹Fakultät für Physik und Geowissenschaften, Institut für Experimentelle Physik II, Universität Leipzig, Linnéstraße 5, 04103 Leipzig — ²Fakultät für Chemie und Mineralogie, Halbleiterchemie, Universität Leipzig, Linnéstraße 3, 04103 Leipzig

The strain-free boron- and indium-containing GaAs compounds are promising candidates for novel III-V semiconductor solar cell absorber materials with lattice match to GaAs, for which experimental data of the electronic band structure are widely unknown. We employ far-infrared magnetooptic ellipsometry to determine the electron effective mass in non-degenerate, silicon-doped, n-type B_0.03In_0.06Ga_0.91As with a electron concentration ranging from 2·10¹⁷ to ∼ 1·10¹⁸cm⁻³ and observe a strong increase of the electron effective mass of 44% in B_0.03In_0.06Ga_0.91As compared to In_0.06Ga_0.94As. Further we report on the vibrational lattice mode behavior of this quaternary alloy. For BAs, an experimentally obscure compound, the curvature of the same conduction band extrapolates to the free electron mass.