Lead free Ba0.99Ca0.01Ti0.98Zr0.02O3 (BCZT) thin films with seed layers were prepared by using sol–gel processing technique. The seed layers, ranging from 10 nm to 40 nm, were introduced between the BCZT films and the Pt(111)/Ti/SiO2/Si substrates. The effects of seed layer thickness on the structure and dielectric properties of the thin films were investigated. With the increase of seed layer thickness, the grain size of the BCZT thin films increases from about 100 nm to 300 nm, accordingly, the dielectric constants decrease at lower frequency. The highest dielectric tunability is 34.5% for the films with a 20 nm-thick seed layer. Improved effective piezoelectric coefficients (d33) were observed in the BCZT thin films. The maximum d33 value of BCZT thin films with a 30 nm-thick seed layer is approximately 70 pm V?1, which is comparable to that of polycrystalline PZT thin films. The seed layer thickness dependence of the electric properties is attributed to the dipole polarization. This demonstrated the possibility to control the microstructure and improve properties of BCZT thin films, which could be exploited for functional devices that demand high quality.
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机译：无铅Ba 0.99 Ca 0.01 Ti 0.98 采用溶胶-凝胶法制备了具有种子层的Zr 0.02 O 3 （BCZT）薄膜。在BCZT薄膜和Pt（111）/ Ti / SiO / small 2 / Si衬底之间引入了从10 nm到40 nm的种子层。研究了种子层厚度对薄膜结构和介电性能的影响。随着种子层厚度的增加，BCZT薄膜的晶粒尺寸从约100 nm增加到300 nm，因此，介电常数在较低频率下降低。对于具有20 nm厚种子层的薄膜，最高的介电可调性为34.5％。在BCZT薄膜中观察到改善的有效压电系数（ d 33 ）。具有30 nm厚种子层的BCZT薄膜的最大 d 33 值约为70 pm V ？ 1 ，可与多晶PZT薄膜相媲美。电特性的种子层厚度依赖性归因于偶极极化。这证明了控制BCZT薄膜的微观结构和改善其性能的可能性，可将其用于要求高质量的功能器件。
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