Piezoelectric Soft MEMS for Tactile Sensing and Energy Harvesting

Flexible piezoelectric heterostructures based on aluminium nitride (AlN) grown on a polymeric soft substrate are shown to be a powerful material system to produce soft and conformable MEMS. Here we report on two different devices based on soft AlN MEMS technology on top of Kapton substrates, such as tactile sensing for robotic applications and energy harvesters from vibrations and air flow. While extremely flexible, the Mo/AlN/Mo structure results to be crack-free even after the microfabrication procedure, peeling off from its rigid support and several cycles of bending. The fabricated tactile sensors exhibit a linear response as a function of pressure, while energy harvesting devices, structured as piezoelectric flexible cantilever, generate a voltage of about 20 mV under just a gentle breath.