Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 14: III-V Halbleiter I
HL 14.4: Vortrag
Dienstag, 12. März 2002, 11:45–12:00, H13
Empirical pseudopotential (EPP) calculations of effective-mass parameters of wurtzite-type GaN, InN, and ALN — •Daniel Fritsch, Heidemarie Schmidt, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften
EPP parameters of the ionic potentials for wurtzite-type GaN, InN, and AlN have been determined based on a simple empty core model and by fitting experimentally determined low-temperature transition energies of nine zincblende-type binary materials (Ga,In,Al/As,P,N). The obtained ionic potentials are identical for common ion types and can be used in our EPP wurtzite bandstructure calculations as well. For the screening of the ionic potentials we take the model dielectric function є(q) derived from Levine and Louie [1] where anisotropic screening, e.g. in wurtzite materials, can easily be incorporated. As a result, we have dealt in detail with the anisotropy of important band structure parameters of wurtzite GaN, InN, and AlN. The determined Luttinger-like parameters Ai, i=1..7, are crucial to the design of wide-gap nitride-based semiconductor devices. Furthermore, we demonstrate by means of EPP calculations with anisotropically and artificially isotropic screened ionic potentials that for wurtzite GaN and AlN the anisotropy of the static dielectric function is of little importance for deriving effective-mass parameters. For wurtzite InN we suggest that the anisotropy of the static dielectric function is substantial and that this anisotropy has to be taken into account by analyzing plasma reflection measurements.
[1] Z.H. Levine and S.G. Louie, Phys. Rev. B 25, 6310 (1982).