Fabrication of freestanding Pt nanowires for use as thermal anemometry probes in turbulence measurements  

作　　者：Hai Le-The Christian Küchler Albert van den Berg Eberhard Bodenschatz Detlef Lohse Dominik Krug 

机构地区：[1]Physics of Fluids Group,MESA+Institute,University of Twente,7522 NB,Enschede,The Netherlands [2]BIOS Lab-on-a-Chip Group,MESA+Institute,University of Twente,7522 NB,Enschede,The Netherlands [3]Max Planck-University of Twente Center for Complex Fluid Dynamics,Göttingen,Germany [4]Max Planck Institute for Dynamics and Self-Organization,37077,Göttingen,Germany

出　　处：《Microsystems & Nanoengineering》2021年第2期155-165,共11页微系统与纳米工程（英文）

基　　金：This work is supported by the Max Planck-University of Twente Center for Complex Fluid Dynamics and by the Netherlands Organisation for Scientific Research(NWO)Gravitation program funded by the Ministry of Education,Culture and Science of the government of the Netherlands.

摘　　要：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,~70µm 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.

关 键 词：NANOWIRES TURBULENCE THERMAL 

分 类 号：TB383[一般工业技术—材料科学与工程]