Modeling and fabrication of single cantilever piezoelectric microgenerator with optimized Zno active layer

Abstract

This paper presents design and fabrication process details of a piezoelectric generator with a thin-film zinc oxide (ZnO) layer. Structure of the piezoelectrical cantilever beam harvester consists of ZnO layer in between two insulating Al2O3 layers and outer aluminium contacts deposited on a silicon substrate. This multilayer system was prepared by the combination of radio-frequency and direct-current magnetron sputtering. Geometrical arrangement of the substrate holder and deposition target was optimized in order to reduce the disruptive effect of the high energy ions bombardment on the ZnO film microstructure. We present ZnO microstructure characterization by means of X-ray diffraction and scanning electron microscopy related to the estimation of internal micro-strains, crystallite sizes and deposition rates. Maximum generated open-circuit voltage achieved close to the cantilever resonant frequency of 595Hz was 0.975V.