Optical and electro-optical properties of Pb(Zr,Ti)O₃ and (Pb,La)(Zr,Ti)O₃ films prepared by aerosol deposition method

We deposited high-transparency, lanthanum-modified lead zirconate titanate [PLZT, Pb_0.91La_0.09(Zr_0.65Ti _0.35)O₃] films, using an aerosol deposition method. The films showed an acceptable scattering loss level for optical devices. The transmittance of the PLZT films increased with the incident angle increase of the PLZT particle beams, because the concentration and size of the impurities, such as pores and PbO particles, decreased with the incident angle. The extinction coefficient of the highly transparent films decreased with the inverse fourth power of the wavelength, which means that the degradation of the film transmittance was due to Rayleigh scattering. This indicates that the sizes of the scattering centers in the films are at least ten times smaller than the measurement wavelength, which is consistent with the TEM observations of the sizes of the crystal grains and impurities. Lead zirconate titanate [PZT, Pb(Zr_0.54Ti_0.46)O₃] films were also successfully deposited with a high transparency, although the PZT bulk ceramics are opaque due to optical anisotropy. Linear and quadratic electro-optical responses were observed for PZT and PLZT films, consistent with the expected bulk properties. The electro-optical coefficients were comparable to those of films deposited using conventional methods, such as the sol-gel and sputtering methods.