Electrooptic properties of highly oriented Pb(Zr,Ti)O_3 film grown on glass substrate using lanthanum nitrate as a buffer layer

摘要

Materials with preferred orientation exhibit unique properties that are frequently improved in comparison with those that are randomly oriented. Optical waveguide devices require high-quality single-crystal-like thin films because of their low optical propagation loss and their near-single-crystal properties. The growth mechanisms of textured films on non-lattice matched amorphous substrates, such as glass, are different from those on single-crystal substrates or the surface of a metal electrode. In this study, highly (100) oriented Pb(Zr,Ti)O_3 PZT films were grown on an amorphous substrate by means of the sol-gel multicoating method, using lanthanum nitrate as a buffer layer. The lanthanum nitrate buffer layer was also very effective as a diffusion barrier against Pb-Si interdiffusion. The electrooptic properties of the PZT films were markedly enhanced when their orientation was adjusted to the (100) direction.