Lead Zirconate Titanate Acoustic Energy Harvesters Utilizing Different Polarizations on Diaphragm

This paper presents improved power generation performances of a PZT microelectromechanical systems (MEMS) acoustic energy harvester having dual top electrodes to utilize different polarizations of charges on the surface of a vibrating PZT diaphragm. The PZT acoustic energy harvester had a diaphragm with a diameter of 2 mm consisting of Al(0.1 μm)/PZT(1 μm)/Pt(0.1 μm)/Ti(0.1 μm)/SiO2(1.5 μm). The top Al electrodes independently cover the peripheral surface and the central surface of the PZT diaphragm. The peripheral energy harvester generated a power of 5.28 × 10-11W, and the central energy harvester generated a power of 4.25 × 10-11 W under the sound pressure level of 100 dB (0.01 W/m2) at the first resonance frequency of 4.92 kHz. A connected energy harvester was also defined between the peripheral electrode and the central electrode. The total power generated by the connected harvesters was 8.28 × 10-11 W that corresponds to the power density of 20.7 μW/m2. The device exhibited nearly two times larger power than the other devices with similar diaphragm areas.