Geometric microengineering of the active layer in a piezoelectric sensor has emerged as a hot topic to improve performance but meets challenges due to the brittle nature of piezoelectric ceramics. Here, we demonstrate that fs-laser-induced compressive stress leads to film bulging in the nanoscale and forms various shapes of nanostructures, including nanobumps, nanovolcanoes, and nanocaves on Pb_1.1Zr_0.52Ti_0.48O₃ (PZT) films, in a single-step, mask-free, large-scale, and rapid fashion. Highly reproducible 3D profiles of the nanostructures are finely controlled by carefully adjusting the laser energy density around the ablation threshold. Evaluation of piezoelectric response to external pressure pulses shows that the PZT films patterned with 450 nm high nanobumps exhibit a 30% increase in output voltage compared to flat PZT films. In a rainfall monitoring test, the PZT films patterned with 450 nm high nanobumps show a significantly enhanced response with varying rain droplet volumes and falling frequencies. Geometric microengineering of PZT films using a femtosecond laser direct writing route provides a guideline for material design in a wide range of microsensor applications.

中文翻译：

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飞秒激光支持的 PZT 薄膜几何微工程，用于增强压电响应和降雨监测演示


压电传感器中有源层的几何微工程已成为提高性能的热门话题，但由于压电陶瓷的脆性而面临挑战。在这里，我们证明了飞秒激光诱导的压应力导致纳米尺度上的薄膜膨胀，并在 Pb_1.1Zr_0.52Ti_0.48O₃ （PZT） 薄膜上形成各种形状的纳米结构，包括纳米凸块、纳米火山和纳米洞穴，以一步、无掩模、大规模和快速的方式。通过在烧蚀阈值附近仔细调整激光能量密度，可以精细控制纳米结构的高度可重复的 3D 轮廓。对外部压力脉冲的压电响应评估表明，与平面 PZT 薄膜相比，具有 450 nm 高纳米凸块图案的 PZT 薄膜的输出电压增加了 30%。在降雨监测测试中，以 450 nm 高纳米凸块为图案的 PZT 薄膜在不同的雨滴体积和下落频率下显示出显著增强的响应。使用飞秒激光直接写入路线对 PZT 薄膜进行几何微工程，为各种微传感器应用中的材料设计提供了指导。