PREPARATION AND STUDY ON COMPOSITIONALLY GRADED Pb(Zr,Ti)O₃ FERROELECTRIC THIN FILMS

ABSTRACT

Compositionally graded Pb(Zr,Ti)O₃ thin films were prepared on platinum-coated silicon substrates by a modified Sol-Gel method and rapid heat-treatment. The composition depth profile of a typical up-graded film was determined by using a combination of auger electron spectroscopy and Ar ion etching. The results confirm that the processing method produces graded composition change. XRD analyses show that the graded thin films possess composite structure of tetragonal and rhombohedral. The dielectric constants of the graded thin films are higher than that of every unit thin films, but loss tangent are similar each other at 10 kHz. The dielectric constants of the up-graded and down-graded films at 10 kHz were found to be 206 and 219, respectively. The Hysteresis loops of the graded thin films showed fine ferroelectric properties. The remnant polarizations (Pr) of the up-graded and down-graded films were 24.3 μC/cm² and 26.8 μC/cm², respectively. The pyroelectric coefficients of the graded thin films were higher than that of every unit thin film. The pyroelectric coefficients of the up-graded and down-graded films were 57.8 and 46.1 nC/cm²K at room temperature, respectively.

Keywords:

• Compositionally graded thin films
• sol-gel
• pyroelectric coefficients

ACKNOWLEDGMENTS

This work was supported by the Ministry of Sciences and Technology of China through 973-progect (No. 2002CB613304) and the Jiangsu Provincial Natural Science Foundation (No. BK2005039).