Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.92: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Growth induced structural defects in BaTiO₃3-ZnO-heterostructures — •Christian Kranert, Tammo Böntgen, Rüdiger Schmidt-Grund, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Semiconductor Physics Group, Institut für Experimentelle Physik II, Leipzig, Germany

The coupling of the switchable and non-switchable polarization of ferroelectric (BaTiO₃) and pyroelectric (ZnO) materials, respectively, in heterostructures results in new physical effects which can be used for modulators, sensors and memories. Their fabrication requires epitaxial growth processes. We present investigations on the crystal structure of BaTiO₃-ZnO-heterostructures grown by pulsed laser depostion using X-Ray diffraction and Raman spectroscopy. The latter was carried out with an excitation wavelength of 325 nm in the absorption regime allowing to study the Raman spectra of ultra-thin (<10 nm) BaTiO₃ layers.

We show that the orientiation of BaTiO₃ grown on ZnO can be switched between (001) and (111) by variation of the growth parameters for a certain range of the layer thickness. Especially the (111)-oriented BaTiO₃ layers exhibit the assembly of a hexagonal impurity phase. Different rotation domains were observed in the top layer (BaTiO₃ on ZnO or vice versa) in agreement with a recent group-theoretical treatment [1].

[1] M. Grundmann et al., Phys. Rev. Lett. 105, 146102 (2010)