title: Bending-induced electromechanical coupling and large piezoelectric response in a micromachined diaphragm.
abstract: We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr₀.₅₂Ti₀.₄₈)O₃ (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC voltage. The curvature of the diaphragm was controlled by applying air pressure to its back. We found that a depolarized flat diaphragm does not initially exhibit electromechanical coupling or the piezoelectric response. However, upon the application of static air pressure to the diaphragm, both electromechanical coupling and the piezoelectric response can be induced in the originally depolarized diaphragm. The piezoelectric response increases as the curvature increases and a giant piezoelectric response can be obtained from a bent diaphragm. The obtained results clearly demonstrate that a high strain gradient in a diaphragm can polarize a PZT film through a flexoelectric effect, and that the induced piezoelectric response of the diaphragm can be controlled by adjusting its curvature.
authors.affiliation: Advanced Nanofabrication Core Lab, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Wang
authors.forename: Yingbang
authors.initials: Y
authors.lastname: Yao
authors.forename: Xianbin
authors.initials: X
authors.lastname: Wang
authors.forename: Weisheng
authors.initials: W
authors.lastname: Yue
authors.forename: Longqing
authors.initials: L
authors.lastname: Chen
authors.forename: Xi Xiang
authors.initials: XX
authors.lastname: Zhang