AlScN thin films on metal substrates for energy harvesting applications AlScN-Dünnschichten auf Metallsubstraten für Energy Harvesting Anwendungen

In this paper, development of energy harvesters attuned to frequencies in the range of 25 Hz to 55 Hz are presented. In a first step, simulations were done to identify substrate geometry and thin film layout to increase the energy harvested in comparison to a basic cantilever design. Based on those results, substrates of 0.3 mm thick steel substrates were fabricated and then coated with piezoelectric AlScN thin films by reactive magnetron sputter process. Depositions were done from metallic Al and Sc targets in a co-sputtering process with Ar-N<inf>2</inf> gas mixture. The fabricated harvesters were characterized in a shaker system regarding their resonance frequency and electrical parameters. The actuations were done with acceleration of 0.5g and the generated voltage was measured depending on frequency and electrical load. The harvesters generated up to ±50 V and Power P<inf>max</inf> between 0.9…1.1 mW.