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Giant piezoelectricity in oxide thin films with nanopillar structure

2020 12 15 Science - Nanopillar region of NNO thin filmFigure 1: Atomically resolved scanning transmission electron microscopic (STEM) images of the nanopillar region of NNO thin film: cross-sectional high-angle annular dark-field (HAADF) (top) and annular bright-field (ABF) (bottom) images.

2020 12 15 Science - Large strain excited by electric field in NNO thin film
Figure 2: Large strain excited by electric field as observed in a NNO thin film with the nanopillar structure.

IMRE led a collaboration team comprising IMRE researchers (Liu Huajun, Chen Yi Fan, Ivan Tan Chee Kiang and Kui Yao),  together with collaborators from IHPC, A*STAR, NUS, Pennsylvania State University and University of Missouri, to discover an innovative strategy to realize local heterogeneity by forming nanopillar structure, as revealed in atomically-resolved electron microscopy, in perovskite oxide thin films with a simplified composition.

The structural distortions around the nanopillar regions lower the crystal symmetry, facilitating domain wall motion and polarization rotation under electric field, resulting in outstanding effective piezoelectric response as supported by theoretical calculations. Forming local heterogeneity with such nanopillars in the perovskite structure could be generally useful for designing and optimizing various functional materials. By implementing such a new strategy to form the nanopillar structure in Na-deficient NaNbO3 thin films, the team demonstrates an environment green lead-free piezoelectric thin film with giant piezoelectric strain, as a potential candidate to replace the current market dominant piezoelectric lead zirconate titanate (PZT) thin film in selected micro-electromechanical system (MEMS) applications.

Huajun Liu et al., "Giant piezoelectricity in oxide thin films with nanopillar structure", Science 369(6501), 292-297 (2020). Also highlighted in Science 369(6501), 252-253 (2020))

Link to online version of paper in Science and Highlight in Science.