Thickness dependent dielectric and piezoelectric properties of BNT–BT–ST thin films

ABSTRACT

0.755Bi_0.5Na_0.5TiO₃–0.065BaTiO₃–0.18SrTiO₃ (BNT–BT–ST) thin films with various thicknesses were grown by sol-gel process. The effects of thickness on structure and electric properties of the films were investigated. The films with lower thickness (≤ 300 nm) show (200) orientation and smaller grain size, while the ralative thicker films(≥ 450 nm) show random orientation and bigger grain size. The leakage current decreases with the increase of thickness. The dielectric, ferroelectric and piezoelectric properties enhance as the thickness increases, which are attributed to the relaxed strain and domain wall motion. The maximum piezoelectric constant is 120 pm/V.

KEYWORDS:

• Thin film
• BNT
• thickness
• dielectric property
• piezoelectric property

Funding

This work was supported by the National Key R&D Program of China (No.2016YFB0402701), the National Natural Science Foundation of China (No. 51372110, 51402144, 51302025 and 51502127), the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University (No. KF201510), the Natural Science Foundation of Shandong Province of China (No. ZR2014JL030 and ZR2016EMM02), the Project of Shandong Province Higher Educational Science and Technology Program (No. J14LA11 and J14LA10).