Bendable transparent ZnO thin film surface acoustic wave strain sensors on ultra-thin flexible glass substrates

Abstract

Flexible and transparent (FT) ZnO thin film based surface acoustic wave (SAW) devices using indium tin oxide (ITO) electrodes were fabricated on ultrathin flexible glass substrates. The influence of annealing process and ITO thickness on the optical properties and acoustic wave power transmission properties of the devices were investigated. The performance of the devices improved significantly when the annealing 10 temperature was raised up to 300 °C. The flexible glass based SAW devices exhibited similar power transmission performance, but have better optical transmittance than those on rigid glass. These FT strain sensors worked well under various applied strains up to ±3000 µε with fast response time, and showed excellent linearity of resonant frequency with the change of strain with a sensitivity of ~34 Hz/με. The strain sensors demonstrated excellent stability and reliability under cyclic bending. The results 15 demonstrated great potential of applications of the FT-SAW device based strain sensors on flexible glass substrates. 65 Willow Glass with a thickness of 100 μm and rigid glass (Corning 2318, 500 μm) were used as the substrates for the device fabrication. The diameter of both the flexible glass and rigid glass wafers was 100 mm. Nanocrystalline ZnO thin films with (0002) crystal orientation were deposited on the substrates by sputtering. 70 Rigid glass was also used to fabricate the SAW devices for comparison. The deposition conditions for the ZnO films were fully optimized through our previous work, 16,17 and were used directly except the deposition temperature which was 100 °C for this work. It was found the crystal structure and optical properties 75 1 S.

Flexible surface acoustic wave strain sensor based on single crystalline LiNbO3 thin film

“…To expand the strain sensing range, we have developed flexible SAW strain sensors using ZnO thin films on flexible glass or polyethylene terephthalate (PET) substrates. 16,17 They have broad strain sensing ranges and good sensitivity, but have inherited shortages of difficulty in controlling device properties and long term stability because of the difficulty in obtaining the exactly same material properties, thickness and defects density of polycrystalline ZnO films.…”

Self-powered transparent glass-based single electrode triboelectric motion tracking sensor array

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Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

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