GaN wire-based Langmuir–Blodgett films for self-powered flexible strain sensors

We report a highly flexible strain sensor which exploits the piezoelectric properties of ultra-long gallium nitride (GaN) wires. Langmuir–Blodgett assembled wires are encapsulated in a dielectric material (parylene-C), which is sandwiched between two planar electrodes in a capacitor-like configuration. Through FEM simulations we show that encapsulating densely aligned conical wires in a properly designed dielectric layer can maximize the amplitude of the generated piezoelectric output potential. According to these considerations we designed and fabricated macroscopic flexible strain sensors (active area: 1.5 cm 2 ). The sensor was actuated in three point configuration inducing curvature radii of less than 10 cm and has a typical force sensitivity of 30 mV N −1 .

S Salomon, J Eymery and E Pauliac-Vaujour

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