Dielectric and Pyroelectric Properties of Compositionally Graded Pb(Zr1-xTix)O3 Thin Films Prepared by Sol-gel Process

Abstract

Compositionally graded ferroelectric lead zirconate titanate Pb(Zr1-xTix)O3 (PZT) thin films were grown on Pt/Ti/SiO2/Si substrates by using a sol-gel process. The final structure consists of six layers, up-graded graded films starting from PbZrO3 on the Pt electrode to the top PZT(50) layer, it consists of no Ti, 10%Ti, 20%Ti, 30%Ti, 40%Ti, and 50%Ti respectively. Whereas films with opposite gradient are called down-graded graded films. Structure and dielectric properties of the graded films was investigated by X-ray diffraction, Auger electron spectroscopy and by impedance analysis. The up-graded and down-graded PZT films annealed at 600C, exhibited the remanent polarization values of 18.0 and 24.2 C/cm2, respectively. The typical small signal dielectric constants and loss tan at a frequency of 100 Hz were 523 and 0.018, 544, and 0.020, respectively, for up-graded and down-graded PZT thin films. The temperature dependence of pyroelectric coefficients of the graded PZT films was measured by a dynamic technique. From 20C to 82C, the pyroelectric coefficients of the up-graded and down-graded PZT films up to 374 and 407 C/m2K, respectively.