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Microstructures and electrical properties of CaCu3Ti4O12 thin films on Pt/TiO2/SiO2/Si substrates by pulsed laser deposition

Published online by Cambridge University Press:  26 August 2011

Sung-Yun Lee
Affiliation:
Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744, Korea
Soon-Mi Choi
Affiliation:
Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744, Korea
Mi-Young Kim
Affiliation:
Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744, Korea
Sang-Im Yoo*
Affiliation:
Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744, Korea
Ji Hye Lee
Affiliation:
Department of Physics, Ewha Womans University, Seoul 120-750, Korea
William Jo*
Affiliation:
Department of Physics, Ewha Womans University, Seoul 120-750, Korea
Young-Hwan Kim
Affiliation:
Nano-Materials Center, Korea Institute of Science and Technology, Seoul 136-791, Korea
Kyoung Jin Choi
Affiliation:
Nano-Materials Center, Korea Institute of Science and Technology, Seoul 136-791, Korea
*
a)Address all correspondence to these authors. e-mail: [email protected]
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Abstract

We investigated microstructures, compositional distributions, and electrical properties of dielectric CaCu3Ti4O12 (CCTO) thin films deposited on Pt/TiO2/SiO2/Si substrates from 700 to 800 °C by pulsed laser deposition. With increasing the deposition temperature from 700 to 750 °C, the dielectric constants (εr) of CCTO films were greatly enhanced from ∼300 to ∼2000 at 10 kHz, respectively. However, the εr values of CCTO films were gradually decreased above 750 °C, which was surely attributable to the formation of a TiO2-rich dead layer at the interface between CCTO and Pt electrode. Compositional analyses by Auger electron spectroscopy, energy dispersive spectroscopy, and electron energy loss spectroscopy revealed that the TiO2-rich dead layer became thicker because of severe Cu diffusion from CCTO films to Pt electrode. The leakage current behaviors of CCTO films are in good agreement with Poole–Frenkel conduction mechanism, where both the TiO2-rich dead layer and rutile TiO2 nanocrystalline particles are considered to play a role of charge trapping centers.

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Articles
Copyright
Copyright © Materials Research Society 2011

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References

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