Electrical properties of ZnO–BaTiO3–ZnO heterostructures with asymmetric interface charge distribution

Authors

V. M. Voora, University of Nebraska-Lincoln
Tino Hofmann, University of Nebraska - LincolnFollow
M. Brandt, Universität Leipzig
M. Lorenz, Universität Leipzig
N. Ashkenov, Universität Leipzig
M. Grundmann, Universität Leipzig
Mathias Schubert, University of Nebraska - LincolnFollow

Date of this Version

2009

Comments

Published in APPLIED PHYSICS LETTERS 95, 2009. Copyright © 2009 American Institute of Physics. Used by permission.

Abstract

We report on capacitance-voltage, current-voltage, Sawyer–Tower, and transient current switching measurements for a ZnO–BaTiO₃–ZnO heterostructure deposited on (001) silicon by using pulsed laser deposition. The triple-layer structure reveals asymmetric capacitance- and current-voltage hysteresis and cycling-voltage dependent Sawyer–Tower polarization drift. We explain our findings by coupling of the ferroelectric (BaTiO₃) and piezoelectric (ZnO) interface charges and parallel polarization orientation of the ZnO layers causing asymmetric space charge region formation under positive and negative bias. The transient current characteristics suggest use of this structure as nonvolatile memory device.