Electromechanical energy demands on homogenous thick films of piezoceramics with sufficiently large piezoelectric constant and reproducible performance. Single‐phase LiTaO₃ films deposited by sol‐gel processing have been fabricated as cantilevers to investigate the interdependence of dielectric and piezoelectric properties as a function of film thickness. Phase pure LiTaO₃ films with varying thickness in the range of 2.07‐4.37 µm on stainless steel substrates were obtained after calcination of samples at 650°C. The relative permittivity of optimized spin‐coated films peaked at 479.73 (1 kHz), whereas the piezoelectric coefficient (d₃₃ mode) determined by piezoresponse force microscopy was in the range of 21‐24 pm/V. The effect of poling was studied through the butterfly and phase curves. A figure of merit (FOM) up to 3.29 (10⁻¹⁸ m²/V²) was determined for cantilever devices, which were able to generate a peak‐to‐peak voltage of 0.046‐0.15 V using a 1 MΩ resistor as an impedance load at a fixed acceleration of 1.5 m/s². While the power density was in the range of ~4‐20 × 10⁻⁹ W/m³, which increased with the increasing film thickness. The leakage current density decreased in the range of 4 × 10⁻⁵‐6 × 10⁻⁷ A/m² in the same direction. As both ferroelectric and piezoelectric properties of LiTaO₃ films are dependent on film thickness, an optimal energy conversion efficiency was obtained for a thickness of ~3 µm. Furthermore, these devices were tested up to a temperature of 150°C for voltage generation. Given the need for lead‐free piezoelectric materials for environmental applications, these LiTaO₃ cantilevers are very promising for vibrational energy harvester (VEH) applications especially due to their cost effectiveness, small size, stability at higher temperatures, and repeatable properties, which makes them suitable for MEMS devices for industrial applications.

中文翻译：

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LiTaO3悬臂梁中压电系数和膜厚度的相互依赖性

机电能量要求压电陶瓷的均质厚膜具有足够大的压电常数和可再现的性能。通过溶胶-凝胶工艺沉积的单相LiTaO ₃薄膜被制成悬臂梁，以研究介电和压电特性随薄膜厚度的相互依赖性。在650°C下对样品进行煅烧后，获得了在不锈钢基板上厚度变化范围为2.07-4.37 µm的纯LiTaO ₃相薄膜。优化的旋涂膜的相对介电常数在479.73（1 kHz）处达到峰值，而压电系数（d ₃₃ 压电响应力显微镜确定的最大模式）在21-24 pm / V的范围内。通过蝶形和相位曲线研究了极化的影响。对于悬臂装置，确定了高达3.29（10 ^-18  m ² / V ²）的品质因数（FOM），这些悬臂装置能够使用1MΩ电阻作为输出来产生0.046-0.15 V的峰峰值电压。固定加速度为1.5 m / s ^2时的阻抗负载。功率密度在〜4-20×10 ^-9  W / m ³的范围内，随着膜厚度的增加而增加。泄漏电流密度在4×10 ^-5 -6×10 ^-7  A / m ²的范围内降低朝着同一方向。由于LiTaO ₃薄膜的铁电和压电特性均取决于薄膜厚度，因此对于〜3 µm的厚度可获得最佳的能量转换效率。此外，对这些设备进行了高达150°C的温度测试以产生电压。鉴于需要在环境应用中使用无铅压电材料，这些LiTaO ₃悬臂在振动能量收集器（VEH）应用中非常有前途，特别是因为它们具有成本效益，体积小，在高温下具有稳定性以及可重复使用的特性，这使得它们成为现实。适用于工业应用的MEMS器件。