We report a robust fabrication method for patterning freestanding Pt nanowires for use as thermal anemometry probes for small-scale turbulence measurements. Using e-beam lithography, high aspect ratio Pt nanowires (~300 nm width, ~70 µm length, ~100 nm thickness) were patterned on the surface of oxidized silicon (Si) wafers. Combining wet etching processes with dry etching processes, these Pt nanowires were successfully released, rendering them freestanding between two silicon dioxide (SiO₂) beams supported on Si cantilevers. Moreover, the unique design of the bridge holding the device allowed gentle release of the device without damaging the Pt nanowires. The total fabrication time was minimized by restricting the use of e-beam lithography to the patterning of the Pt nanowires, while standard photolithography was employed for other parts of the devices. We demonstrate that the fabricated sensors are suitable for turbulence measurements when operated in constant-current mode. A robust calibration between the output voltage and the fluid velocity was established over the velocity range from 0.5 to 5 m s⁻¹ in a SF₆ atmosphere at a pressure of 2 bar and a temperature of 21 °C. The sensing signal from the nanowires showed negligible drift over a period of several hours. Moreover, we confirmed that the nanowires can withstand high dynamic pressures by testing them in air at room temperature for velocities up to 55 m s⁻¹.

我们报告了一种稳健的制造方法，用于图案化独立式 Pt 纳米线，用作小规模湍流测量的热风速探针。使用电子束光刻，在氧化硅 (Si) 晶片的表面上图案化高纵横比 Pt 纳米线（~300 nm 宽度，~70 µm 长度，~100 nm 厚度）。将湿法蚀刻工艺与干法蚀刻工艺相结合，这些 Pt 纳米线被成功释放，使它们独立于两种二氧化硅（SiO ₂) 梁支撑在硅悬臂上。此外，固定设备的桥的独特设计允许在不损坏 Pt 纳米线的情况下轻轻释放设备。通过将电子束光刻的使用限制为 Pt 纳米线的图案化，而将标准光刻用于器件的其他部分，从而最大限度地减少了总制造时间。我们证明制造的传感器在恒流模式下运行时适用于湍流测量。在 SF _{6 中}在0.5 到 5 m s ^-1的速度范围内建立了输出电压和流体速度之间的稳健校准压力为 2 巴，温度为 21 °C。来自纳米线的传感信号在几个小时内的漂移可以忽略不计。此外，我们通过在室温下在空气中以高达 55 m s ^{-1 的}速度对其进行测试，证实纳米线可以承受高动态压力。