Yi Jiaojiao, Liu Lisha, Shu Liang, Huang Yu, Li Jing-Feng
Laboratory of Advanced Multicomponent Materials, School of Mechanical Engineering, Jiangsu University of Technology, Changzhou 213001, P. R. China.
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing, P. R. China.
ACS Appl Mater Interfaces. 2022 May 11;14(18):21696-21704. doi: 10.1021/acsami.2c03137. Epub 2022 Apr 28.
As a promising lead-free ferroelectric, BiFeO has a very large intrinsic polarization of ∼100 μC/cm, enabling its great potential in electronic applications especially in a film format. In this sense, reliable ferroelectric properties are desired; however, pure-phase BiFeO films are notorious for their large leakage current, especially of those processed by using the sol-gel method─a facile and industrially scalable method for film preparation. In this study, a protection layer, which can be easily integrated in the sol-gel process, is used to ensure the acquirement of remnant polarization of ∼65 μC/cm in ∼200 nm BiFeO thin films, whereas O annealing can enhance that to ∼120 μC/cm in ∼400-700 nm films. Reliable ferroelectricity of BiFeO films on Si wafers within a wide thickness range was thus achieved. The obtained ferroelectricity is among the best-achieved properties to date of BiFeO films for both thin and intermediate thicknesses, including both chemically and physically derived. These results are helpful to advance potential use of sol-gel-processed BiFeO films in electromechanical devices with different desired thicknesses.
作为一种有前景的无铅铁电体，BiFeO具有约100 μC/cm的非常大的固有极化强度，使其在电子应用中具有巨大潜力，特别是以薄膜形式。从这个意义上说，需要可靠的铁电性能；然而，纯相BiFeO薄膜因其大漏电流而声名狼藉，尤其是那些通过溶胶 - 凝胶法制备的薄膜——一种用于薄膜制备的简便且可工业扩展的方法。在本研究中，一种可轻松集成到溶胶 - 凝胶工艺中的保护层被用于确保在约200 nm的BiFeO薄膜中获得约65 μC/cm的剩余极化强度，而氧退火可在约400 - 700 nm的薄膜中将其提高到约120 μC/cm。从而在宽厚度范围内的硅片上实现了可靠的BiFeO薄膜铁电性。所获得的铁电性是迄今为止BiFeO薄膜在薄和中等厚度方面（包括化学和物理衍生的）所取得的最佳性能之一。这些结果有助于推动溶胶 - 凝胶法制备的BiFeO薄膜在具有不同所需厚度的机电装置中的潜在应用。
