Electro-optical Property of Sol-gel-derived PLZT7/30/70 Thin Films

Pb0.93La0.07(Zr0.3Ti0.7)0.93O3\rm{Pb}_{0.93}\rm{La}_{0.07}(\rm{Zr_{0.3}}\rm{Ti_{0.7}})_{0.93}O_{3} (PLZT7/30/70) thin films with and without a seeding layer of PbTiO3 (PT) were successfully deposited on indium-doped tin oxide coated glass substrate via a sol-gel process, and a top conducting SnO2 thin film is also sol-gel-derived. The thicknesses of PLZT and PT layer are 0.5µm and 24nm, respectively. The retardance was enhanced by application of a seeding layer of PT and measured by a new developed heterodyne interferometer. The Pockels linear electro-optical coefficient of PLZT film with a PT layer was determined to be 3.17×10-9m/V when the refractive index is consider as 2.505, which is one order larger than 1.4×10-10m/V for PLZT12/40/60 reported in the literature. From the comparisons, the average transmittance of PLZT film with a PT seeding layer was 70.3%, higher than 62.9% in PLZT film. The rootmean- square roughness of PLZT thin film with a PT layer was determined just 6.87nm. Over all, experimental results implies that the addition of a PT seeding layer to PLZT film plays a significant role in the increase of retardance and then the PLZT film exists a higher Pockels coefficient.