Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 11: II-VI Halbleiter I
HL 11.5: Vortrag
Freitag, 4. März 2005, 16:00–16:15, TU P164
Empirical Pseudopotential Calculation of Zn1−xMgxO (0≤x≤1) — •Daniel Fritsch, Heidemarie Schmidt, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Fakultät für Physik und Geowissenschaften
We have investigated the electronic properties of the ternary alloy Zn1−xMgxO (0≤x≤1) by means of the Empirical Pseudopotential Method (EPM). Making use of transferable ionic model potential parameters we obtained the band dispersions of wurtzite ZnO and rocksalt MgO that compare to low-temperature experimental data, thereby validating the transferability of the used EPM parameters. Those transferable parameters are a good starting point for EPM calculations of the ternary alloy ZnMgO by means of the Virtual Crystal Approximation (VCA). We present the calculated band structures of Zn1−xMgxO for 0≤x≤1 where the alloy dependent crystal modification is wurtzite for x ≤ 0.6 and rocksalt for x ≥ 0.7. For a better comparison with room-temperature experimental studies we weighted the EPM parameters with temperature dependent Debye-Waller factors by means of a model introduced by Brooks and Yu.
The obtained room-temperature band structures are discussed with respect to electronic band-to-band transitions leading to critical points in the dielectric function of Zn1−xMgxO measured by spectroscopic ellipsometry in the energy range from 0.75 eV up to 9 eV.