Mechanically Tunable Nonlinear Dielectrics
Deng-Li Ko1*, Jie Jiang2, Huang Jun Wei1, Ying-Hao Chu1,3,4
1Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
2Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Hunan, China
3Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan
4Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
* Presenter:Deng-Li Ko
In the past decade, strain engineering has been used to markedly manipulate characteristics of dielectric materials such as increasing tunability. However, the ways to apply strain into materials such as hydrostatic pressure, strong magnetic, electric and lattice mismatch are difficult to achieve in general environment and our daily life. In this study, we adopt flexible muscovite mica substrate to surmount this obstacle and fabricate (Ba0.5Sr0.5) TiO3 (BSTO) thin film which has high and tunable dielectric constant on mica substrate via van der Waals epitaxy. The combination of X-ray diffraction and high-resolution transmission electron microscopy was conducted to reveal the heteroepitaxy of the BSTO/muscovite system. The dielectric behaviors against mechanical bending were highlighted by the capacitance-voltage measurement under various bending conditions, ranging from 5~15 mm radius of curvature including tensile and compressive strain. In the bending measurement, the dielectric constant of BSTO thin films with different thicknesses was altered nonlinearly from -8% to 13% compared with the unbent state. Furthermore, there is also a release test after the bending measurement to confirm that the BSTO heteroepitaxial structures maintain the physical and tunable dielectric properties. Such a flexible BSTO/muscovite system contributes a path way to apply strain on thin film and develop a flexible and tunable dielectric material.

Keywords: Flexible dielectric materials, Barium strontium titanite (BaxSr1-x) TiO3, muscovite mica, van der Waals epitaxy