The properties of lead titanate thin films derived from a diol-based sol-gel process

The La-modified lead titanate (PLT) thin films were deposited on Pt/SiO2/Si substrates by spin coating with sol-gel processing. 1,3-propandiol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of high quality thin film. By changing the La content (0-20 mol%) and heating temperature (500-800 degrees C), the effects of various processing parameters on the films characteristics are studied. With the increase of La content, the relative dielectric constant (epsilon(r)) of PLT thin film increases from 53 up to 101 with a maximum existing at the heating temperature of 700 degrees C. It was found that the dielectric loss factor (tan delta), coercive field (E-c) and remanent polarization (P-r) decreased, but pyroelectric coefficient (gamma) increased with the increase of La content. The PLT thin film exhibits a lower current density and a larger pyroelectric coefficient at heating temperature of 700 degrees C and La content of 20 mol%.