Crystallographic Facet Engineering Enhances Piezoelectric Response in Laser-Induced Periodic Surface Structures of...

Crystallographic facet engineering in functional oxides, such as lead zirconate titanate (PZT), offers a potent route to enhance piezoelectric properties. Yet, selective exposure of high-energy facets remains challenging with conventional methods. This study demonstrates an enhanced piezoelectric response in PZT epitaxial thin films through crystallographic facet engineering achieved via femtosecond laser-induced periodic surface structures (LIPSSs). LIPSS structures (period: 247 ± 3 nm, height: 380 ± 5 nm) preserving the film's crystallinity and epitaxy and oriented along various crystallographic directions are obtained by precisely controlling laser polarization direction. Crucially, this laser processing enables the selective exposure of specific crystallographic facets, particularly the high-energy {110} planes. Piezoelectric performance tests reveal a dramatic enhancement: the PZT-{110}LIPSS sample exhibits a peak open-circuit voltage of 65.25 mV, a 12.3-fold increase over a dense film (5.3 mV), which is directly attributed to the multiphysics synergistic effects introduced by its unique nanostructure. Piezoresponse force microscopy confirms an approximately 30% reduction in the coercive field and a homogenized domain structure with postlaser treatment. Surface chemistry analysis indicates modified chemical states, including increased oxygen vacancy concentration (30.7-36.1%) and adsorbed oxygen (19.5-26.8%). This work establishes LIPSSs as an innovative and powerful technique for crystallographic facet engineering in nanostructures, significantly enhancing the piezoelectric response of PZT for microelectrical device applications.