Effect of Li substitution on dielectric and ferroelectric properties of ZnO thin films grown by pulsed-laser ablation

Dhananjay, * and Nagaraju, J and Krupanidhi, SB (2006) Effect of Li substitution on dielectric and ferroelectric properties of ZnO thin films grown by pulsed-laser ablation. In: Journal of Applied Physics, 99 (3). 034105-1.

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Abstract

Li-doped ZnO thin films (Zn1-xLixO, x=0.05-0.15) were grown by pulsed-laser ablation technique. Highly c-axis-oriented films were obtained at a growth temperature of 500 degrees C. Ferroelectricity in Zn1-xLixO was found from the temperature-dependent dielectric constant and from the polarization hysteresis loop. The transition temperature (T-c) varied from 290 to 330 K as the Li concentration increased from 0.05 to 0.15. It was found that the maximum value of the dielectric constant at T-c is a function of Li concentration. A symmetric increase in memory window with the applied gate voltage is observed for the ferroelectric thin films on a p-type Si substrate. A ferroelectric P-E hysteresis loop was observed for all the compositions. The spontaneous polarization (P-s) and coercive field (E-c) of 0.6 mu C/cm(2) and 45 kV/cm were obtained for Zn0.85Li0.15O thin films. These observations reveal that partial replacement of host Zn by Li ions induces a ferroelectric phase in the wurtzite-ZnO semiconductor. The dc transport studies revealed an Ohmic behavior in the lower-voltage region and space-charge-limited conduction prevailed at higher voltages. The optical constants were evaluated from the transmission spectrum and it was found that Li substitution in ZnO enhances the dielectric constant.

Item Type:	Journal Article
Publication:	Journal of Applied Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute of Physics.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	16 Sep 2010 09:40
Last Modified:	19 Sep 2010 06:15
URI:	http://eprints.iisc.ac.in/id/eprint/31814

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