SIC/ALN PIEZOELECTRIC ENERGY HARVESTERS FOR PULSED PRESSURE SOURCES IN HARSH ENVIRONMENT APPLICATIONS

Piezoelectric micromachined circular diaphragm energy harvesters for pulsed pressure sources have been fabricated and characterized. These devices utilize silicon carbide (SiC) as the structural material and aluminum nitride (AlN) as the active piezoelectric element to enable operation within harsh environments. In particular, the SiC/AlN energy harvesting device yields an output power density of 20 μW/cm and rms voltage of 0.2 V under pressure pulses of 1.09 psi (rms) at 2 kHz. Fabricated SiC/AlN harvester has been characterized at elevated temperatures as high as 250°C. This work not only demonstrates the first harsh environment energy harvesters based on SiC and AlN for a pulsed pressure environment, but also addresses its potentials for integrating energy harvesting power source with SiC circuitry and enabling self-powered wireless sensors. This type of sensing system can be used for the real-time monitoring of harsh environment energy system such as automotive engines, gas turbines and geothermal wells.