Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 46: Poster 2
HL 46.68: Poster
Donnerstag, 29. März 2007, 15:00–17:30, Poster A
Ferroelectric properties of BaTiO3 - ZnO heterojunctions — •Matthias Brandt1, Holger von Wenckstern1, Holger Hochmuth1, Michael Lorenz1, Marius Grundmann1, Jürgen Schubert2, Venkata Voora3, and Mathias Schubert3 — 1Universität Leipzig, Institut für Experimentelle Physik II, Leipzig, Germany — 2IBN 1-IT and cni, Forschungszentrum Jülich GmbH, Jülich, Germany — 3Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, U.S.A.
Bariumtitanate (BTO), as many materials in the perowskite structure, exhibits a spontaneous polarization which is switchable by an external electric field if the crystal exists in its ferroelectric phase (below the curie temperature of ≈ 120 ∘C). ZnO, a wurtzite crystal, shows a spontaneous polarization parallel to its crystallographic c axis, regardless of the outer field. Within this work, BTO films have been grown by pulsed laser deposition (PLD) on various substrates (Si, Pt, STO with SRO buffer, STO:Nb). Formation of heterojunctions between these materials leads to the occurrence of unique coupling effects. These cause polarization hysteresis, which we observed in electrical and electro-optical measurements. Structural, optical and electrical properties of these heterojunctions will be compared to results obtained from bare BTO layers. Further a model of the polarization exchange coupling was developed, and will applied to analyze the experimental data.