X-ray diffraction and Raman investigations of thickness dependent stress effects on Pb(Zr_xTi_1-x)O₃ thin films

Microstructure, film orientation, and optical transmission spectra of polycrystalline Nd-modified Pb(ZrxTi1−x)O3 films were studied as a function of film thickness. Pulsed laser deposition was used for the fabrication of films with thickness from 80to465nm on single-crystal MgO(100) substrates. Raman spectroscopy, x-ray diffraction, and spectrophotometry measurements were utilized in the film characterization. With the decreasing film thickness, films first oriented with c axis perpendicular to film surface, and then, after some critical thickness, changed to a-axis orientation. At the same time, compressive stress increased up to 1.3GPa and a clear blueshift of the optical absorption edge was found in transmission spectra