Piezoelectric micro energy harvesters employing advanced (Mg,Zr)-codoped AlN thin film

We report the new doped-AlN thin film, (Mg,Zr)AlN, based micro energy harvester. By co-doping Mg and Zr into AlN crystal, (Mg,Zr)AlN shows giant piezoelectricity and preserves low permittivity. (Mg,Zr)AlN has higher figure of merit (FOM = e
₃₁
²
/(ε
₀
ε)) than conventional PZT. The 13 at.%-(Mg,Zr)AlN had the experimental FOM of up to 16.7 GPa. The micromachining harvester provided the high normalized power density of 3.72 mW.g
^-2
.cm
^-3
. This achievement was 1.5-fold increase compared to state of the art.