High power Co3O4/ZnO p–n type piezoelectric transducer

Abstract

Enhancing the output power of piezoelectric transducer is essential in order to supply sufficient and sustainable power to wireless sensor nodes or electronic devices. In this work, a Co3O4/ZnO p–n type power piezoelectric transducer which can be operated at low frequencies has been developed by utilizing n-type semiconducting zinc oxide (ZnO) and p-type semiconducting tricobalt tetroxide (Co3O4). We utilize ZnO to be the piezoelectric transducer and build a multi-layer (Au/Co3O4/ZnO/Ti) thin film structure. The ZnO thin film with preferred orientation along the (002) plane was deposited under optimized deposition conditions on the flexible titanium (Ti) foil with thickness of 80μm. The Co3O4/ZnO interface forms a p–n junction and increases the difference in Fermi levels between the two electrodes, resulting in the great enhancement of output power. The measured output power of the p–n type piezoelectric transducer with optimal resistance of 100kΩ is 10.4μW at low operating frequency of 37Hz, which is 10.9 times of output power of ZnO piezoelectric transducers.