Structural and electrical characterization of hydrothermally deposited piezoelectric (K,Na)(Nb,Ta)O3 thick films
Structural and electrical characterization of hydrothermally deposited piezoelectric (K,Na)(Nb,Ta)O3 thick films
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DOI：
10.1007/s10853-020-04663-x
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发表时间：
2020-04
影响因子：
4.5
通讯作者：
T. Shiraishi;Yuta Muto;Yoshiharu Ito;T. Kiguchi;Kazuhisa Sato;M. Nishijima;H. Yasuda;H. Funakubo-H.-Funaku
中科院分区：
文献类型：
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作者：
T. Shiraishi;Yuta Muto;Yoshiharu Ito;T. Kiguchi;Kazuhisa Sato;M. Nishijima;H. Yasuda;H. Funakubo-H.-Funaku
采用水热法在（001）La：SrTiO 3和（001）cSrRuO 3//（001）SrTiO 3衬底上于200 °C外延生长了（K 0. 89 Na 0. 11）（Nb 0. 85 Ta 0. 15）O3厚膜，并对其晶体结构和电学性能进行了研究。薄膜厚度随沉积时间增加而增加，在10 h内达到6 µm。高温X射线衍射测试表明，在120 ° C和400 °C时，分别发生了从正交相到四方相和从四方相到立方相的连续相变。用电子显微镜进行微观结构分析，发现存在两种宽度小于等于100 nm的条纹图案，用扫描透射电子显微镜-能量色散X射线能谱仪进行元素分布分析，发现沉积膜的Nb/（Nb + Ta）比值在700 nm左右发生突变。在30 kV/cm时，500 °C退火使漏电流密度从102 A/cm 2降低到10-5A/cm 2，表明退火是提高绝缘性的有效方法。相对介电常数（εr）随频率的增加而线性下降，在10 kHz时达到450。利用压电力显微镜测量了（K，Na）（Nb，Ta）O3厚膜的极化-电场迟滞回线和场致应变曲线，结果表明，（K，Na）（Nb，Ta）O3厚膜的反射极化（Pr）为30 µC/cm 2，压电常数（d33，PFM）为70 pm/V。
(K0.89Na0.11)(Nb0.85Ta0.15)O3thick films were epitaxially grown at 200 °C on (001)La:SrTiO3and (001)cSrRuO3//(001)SrTiO3substrates by hydrothermal method, and their crystal structures and electrical properties were investigated. Film thickness increased with deposition time and reached 6 µm in 10 h. High-temperature X-ray diffraction measurement showed that successive phase transitions from orthorhombic to tetragonal and from tetragonal to cubic phases take place at 120 and 400 °C, respectively. Microstructure analyses were performed by using electron microscopy, which revealed the existence of two types of stripe patterns with a width of 100 nm or less. In addition, scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy elemental mapping showed that Nb/(Nb + Ta) ratio of the deposited films abruptly changed around 700 nm in thickness. Annealing at 500 °C led to the reduction in leakage current density from 102to 10–5A/cm2at 30 kV/cm, showing that annealing is an effective way to improve insulation. Relative dielectric constant (εr) decreased linearly with increasing frequency, reaching 450 at 10 kHz. Polarization–electric field hysteresis loop and field-induced stain curve were measured by piezoelectric force microscopy, which showed remanent polarization (Pr) of 30 µC/cm2and piezoelectric constant (d33,PFM) of 70 pm/V. These results demonstrate that (K,Na)(Nb,Ta)O3thick films with superior electrical properties can be fabricated by the low-temperature deposition technique.