Improved transverse piezoelectric properties in {110}-oriented B-site acceptor doped PLZT (8/65/35) thin films

Abstract

ABSTRACTSuperior piezoelectric properties of lead-based perovskite type solid solution systems such as PLZT, having compositions near morphotropic phase boundary (MPB) make them ideal candidates for MEMS. The dielectric and piezoelectric characteristics in such perovskite based thin films are related to their structure and texture. In this study, we report the influence of aliovalent B-site acceptor dopants (Fe3+, Cu2+ and Mn3+) on the structure, dielectric and piezoelectric properties of {110}- preferentially oriented PLZT (8/65/35) thin films. Thin films having a thickness of 2.0 µm were prepared on silicon substrates (111) Pt/Ti/SiO2/Si by Sol-gel spin coating technique. The preferential crystallographic orientation and crystalline phase formation in the thin films were analysed by X-ray diffraction and Raman spectroscopy respectively. The improved transverse piezoelectric coefficient, e31,f and electric field induced bipolar strain characteristics of the acceptor doped PLZT films have been correlated with their crystal structure. Mechanism for higher bipolar strain in Cu2+ and Mn3+ doped PLZT films have also been studied and are reported.