The properties of sol-gel derived PCT pyroelectric thin films

Polycrystalline thin films of Ca-modified lead titanate (PCT) were deposited on Pt/SiO2/Si substrates using a diol-based sol-gel process. Calcium acetylacetonate hydrate was adopted as a starting material instead of calcium acetate or calcium nitrate tetra-hydrate used in general. By changing the Ca content (5 similar to 35 mol%) and heating temperature (500 similar to 800 degrees C), the influences of various processing parameters on the characteristics of thin films are studied. With the increase of Ca content, the relative dielectric constant (epsilon (r)) of PCT thin film increases from 43 up to 70 at the heating temperature of 700 degrees C. It was found that the coercive field (Ec) and the remanent polarization (Pr) decreased, but the pyroelectric coefficient (r) increased with an increase of Ca content. The results show that PCT thin film exhibits the largest figures of merit for the voltage responsivity and the specific detectivity at heating temperature of 700 degrees C and Ca content of 25 mol%.