Effect of scandium concentration on the performances of cantilever based AlN unimorph piezoelectric energy harvester with silicon nitride substrate

Abstract

Microelectromechanical systems (MEMS) offer its ability to sense, control and actuate on sub-micron scale and exhibit its effect on macro scale. To implement any specific MEMS system, small, efficient and long-lifespan micro power sources are required. Piezoelectric energy harvester (PEH) along with radioactive source is one of the most promising approaches to harness electrical energy at micro to millimeter range. In this report, a scandium (Sc) doped Aluminium Nitride (AlN) unimorph piezoelectric energy harvester has been demonstrated. Unimorph piezoelectric layer is built on Silicon Nitride (Si₃N₄) substrate platform that act as cantilever beam and that can be vibrated by inbuilt radioactive system. In particular, Si₃N₄ as cantilever material and the impact of Sc doping concentration on electrical and mechanical properties of AlN piezoelectric thin film materials have been studied in MATLAB simulation platform. Results obtained from numerical study suggests that the proposed energy harvester model composed of AlScN unimorph piezoelectric (with 10% Sc doping concentration, Sc-10%) layer and Si₃N₄ cantilever can yield a maximum power output of ~ 19.33 μW and overall mechanical energy conversion efficiency of ~ 91.07%. These are the maximum output power and mechanical energy conversion efficiency numerically obtained from Sc doped AlN piezoelectric energy harvester systems to the best of our knowledge.