Corrugated aluminum nitride energy harvesters for high energy conversion effectiveness

Aluminum nitride energy harvesters based on corrugated cantilever structures have been proposed, designed and demonstrated by means of micromachining processes with high energy conversion effectiveness. Corrugated cantilever design with a single piezoelectric layer prevents the common problem of an energy cancellation issue in a piezoelectric cantilever, by using a simple fabrication process similar to those in making the unimorph energy harvesters. Furthermore, corrugated structure can have an energy conversion effectiveness comparable to a conventional bimorph design. Experimentally, a prototype energy harvester with measured resonance frequency of 2.56 kHz has been fabricated. Under an input acceleration of 0.25 G, the amplitude of output voltage from the energy harvester has been recorded as 92 mV at a load resistance of 0.86 M Omega and the calculated output power is 4.9 nW. Furthermore, a multifold device resonating at 853 Hz with output power of 0.17 mu W under acceleration of 1 G has been recorded.