Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 51: Poster IV
HL 51.29: Poster
Donnerstag, 28. Februar 2008, 16:30–19:00, Poster D
Charge accumulation in a type-II Ge/Si-heterostructure — Christoph Henkel1, Gisela Biehne1, Marius Grundmann1, Gerald Wagner2, Mathieu Stoffel3, Oliver Schmidt4, and •Heidemarie Schmidt5 — 1Universität Leipzig, Institut für Experimentelle Physik II — 2Universität Leipzig, Institut für Mineralogie, Kristallographie und Materialwissenschaft — 3MPI für Festkörperforschung, 70569 Stuttgart — 4IFW Dresden, Institut für Integrative Nanowissenschaften — 5Forschungszentrum Dresden-Rossendorf e.V., Institut für Ionenstrahlphysik und Materialforschung
The main motivation for mixing a small amount of Ge into Si for example by the self-organized growth of a stack of Ge dots into Si [1], is the controlled modification of the electronic band structure in strained Si namely charge carrier mobility and optical transition probabilities. We report on charge accumulation in fivefold stacks of Ge quantum dots embedded in the n-region of a p+n-Si diode. By means of thermal admittance spectroscopy, capacitance voltage and deep level transient spectroscopy measurements [2] electron confinement in the type II Ge/Si-heterostructures, barrier effects of the quantum wells and wetting layers and defect states in the n-region of the sample associated with the surrounding Si-matrix have been probed. By relating these results to the self consistently modeled electronic band-structure and capacitance voltage characteristic charge accumulation in quantum confined electron states in the investigated type II Ge/Si-heterostructures is clearly revealed. [1] A. Malachias et al., Thin Solid Films 515, 5587 (2007)[2] M. Gonschorek et al., Phys. Rev. B 74, 115312 (2006)