Advances in the areas of wireless technology and low-power electronics stimulated extensively research in energy harvesting from environmental vibration sources. Aluminium nitride (AlN) thin films are promising for piezoelectric microsensors/ microactuators as well as for energy harvesting devices, due to their interesting material properties including good piezoelectric and electromechanical coupling coefficients, low permittivity and high Young's modulus. Despite this, few works reported on the AlN employment for the realization of micro power generators. In such cases, devices have a typical flat cantilever shape (M. Marzencki et al. 2008, R. Elfrink et al. 2009) and sizes are larger than that of most typical MEMS devices. This paper reports on the fabrication and analysis of bent AlN cantilever resonators based on a novel and simple fabrication process without additional proof masses for energy harvesting at frequencies around 2 KHz.
Bent AlN Piezoelectric Resonators for Vibrational Energy Harvesting / M. T., Todaro; G., Caretto; G., Epifani; A., Campa; Bertacchini, Alessandro; Larcher, Luca; A., Passaseo; M., De Vittorio. - ELETTRONICO. - (2011), pp. 1-2. (Intervento presentato al convegno International Workshop on Piezoelectric Materials and Applications - 6 th Annual Energy Harvesting Workshop tenutosi a Roanoke, Virginia, USA nel August 7-11).