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

ABSTRACT

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).