Chemistry of surface nanostructures in lead precursor-rich PbZr 0.52 Ti 0.48 O 3 sol-gel films

Abstract : We present a study of the chemistry of the nanostructured phase at the surface of lead zirconium titanate PbZr 0.52 Ti 0.48 O 3 (PZT) films synthesized by sol-gel method. In sol-gel synthesis, excess lead precursor is used to maintain the target stoichiometry. Surface nanostructures appear at 10% excess lead precursor whereas 30% excess precursor inhibits their formation. Using the surface-sensitive, quantitative X-ray photoelectron spectroscopy and glancing angle X-ray diffraction we have shown that the chemical composition of the nanostructures is ZrO 1.82−1.89 rather than pyrochlore often described in the literature. The presence of a possibly discontinuous layer of wide band gap ZrO 1.82−1.89 could be of importance in determining the electrical properties of PZT-based metal-insulator-metal heterostructures.