Textured Bi1/2Na1/2TiO3‐BaTiO3 Lead‐Free Films with Enhanced Piezoelectric Property and Depolarization Temperature

Abstract Future microelectromechanical systems will need environmentally friendly lead‐free piezoelectrics in the form of thin films, like Bi 1/2 Na 1/2 TiO 3 (BNT); however, its application is limited due to the relatively low depolarization temperature ( T d ). In this work, not only enhanced piezoelectric properties, but also higher T d , are achieved in (001)‐textured 0.94Bi 1/2 Na 1/2 TiO 3 ‐0.06BaTiO 3 (BNT‐BT6) thin films on widely used platinized Si wafers with a LaNiO 3 buffer layer. The piezoelectric coefficient a 33,eff is increased by 65% to 43 pm V −1 in the textured films from 26 pm V −1 in the nontextured counterparts. The texturing also raises the T d to ≈140 °C, about 40 °C higher than that in nontextured films. The increase of T d is attributed to the in‐plane tensile thermal stress and the (001)‐textured structure. The present work provides a guideline to improve piezoelectric properties and the thermal stability of BNT‐based lead‐free piezoelectric thin films.