Wang, Y., Wu, H., Qin, X., Yao, K., Pennycook, S. J., Tay, F. E. H., Adv. Electron. Mater. 2019, 5, 1800691. https://doi.org/10.1002/aelm.201800691
Abstract:
Lead-free 0.95(K0.48Na0.52)(Nb0.95Sb0.05)O3-0.05Bi0.5(Na0.82K0.18)0.5ZrO3 (KNSN-BNKZ0.05) piezoelectric films with preferred crystal orientation and enhanced thickness were fabricated on silicon substrates from a chemical solution approach. Adequate K excess was introduced to obtain a single perovskite phase in the resulting thicker films. The effects of thickness, crystal orientation, and structure of the films on the performance were investigated. Outstandingly large effective piezoelectric strain coefficient up to 250 pm V-1 was demonstrated over a macroscopic scale using a laser scanning vibrometer in the [100]-KNSN-BNKZ0.05 film with an enhanced thickness of 2.7 µm, competitive to the benchmark oriented PZT films on silicon. Atomically-resolved electron microscopy revealed the coexistence of oriented ferroelectric rhombohedral (R) and tetragonal (T) phases at the nanometer scale with gradual polarization rotation, which can lower the domain wall energy and facilitate the large piezoelectric response. The increased film thickness reduced the in-plane mechanical clamping to enable more free deformation in the thickness direction and improve domain wall mobility, both further contributing to enhanced piezoelectric response.
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Funding Info:
The authors acknowledge the research grant support in part by the Singapore Ministry of National Development and National Research Foundation under L2NIC Award No. L2NICCFP1-2013-9, with project code of IMRE/14-9P1112, the partial supports from National Research Foundation Competitive Research Programme, NRF-CRP15-2015-04, IMRE/16-9P1122, and facility support at IMRE, and S/TEM and High Performance Computing facility support from National University of Singapore. S.J.P. would like to acknowledge funding from the Ministry of Education, Singapore under its Tier 2 Grant (Grant No. MOE2017-T2-1-129).
Description:
This is the peer reviewed version of the following article: Wang, Y., Wu, H., Qin, X., Yao, K., Pennycook, S. J., Tay, F. E. H., Adv. Electron. Mater. 2019, 5, 1800691. https://doi.org/10.1002/aelm.201800691, which has been published in final form at https://doi.org/10.1002/aelm.201800691. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.