XPS analysis of surface layer of sol-gel-derived PZT thin films

The crystalline phase and composition of sol-gel-derived lead zirconate titanate (PZT) thin films were successfully analyzed by X-ray photoelectron spectroscopy (XPS). The crystalline phase was determined from deconvolution of Zr3d photoelectron spectra, in which the binding energy reflected the distance from the neighboring ions. The composition was estimated by using the calibration equations, which were induced from the relation between the photoelectron intensities and the molar ratio of ions. The surface layers with a thickness of several tens nm were found to be different crystallographically and compositionally from the inside of the films; they were composed of the rhombohedral phase, and Pb and Ti contents in them were less than those from the inside. The energy dispersive X-ray spectroscopic (EDS) analysis of the cross-section of the thin films confirmed for these findings.