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/Si O2/Si substrates by spin coating with sol-gel processing. 1,3-propandi ol was used as solvent to minimize the number of cycles of spin coatin g and drying processes to obtain the desired thickness of high quality thin film. By changing the La content (0-20 mol%) and heating tempera ture (500-800 degrees C), the effects of various processing parameters on the films characteristics are studied. With the increase of La con tent, the relative dielectric constant (epsilon(r)) of PLT thin film i ncreases from 53 up to 101 with a maximum existing at the heating temp erature of 700 degrees C. It was found that the dielectric loss factor (tan delta), coercive field (E-c) and remanent polarization (P-r) dec reased, but pyroelectric coefficient (gamma) increased with the increa se of La content. The PLT thin film exhibits a lower current density a nd a larger pyroelectric coefficient at heating temperature of 700 deg rees C and La content of 20 mol%.