Design and Fabrication of Micro-energy Harvesters Based on Multilayered Piezoelectric Thin Films

Abstract

With rapid development of diverse wireless sensors for the Internet of Things (IoT) and wearable electronic devices, the demand of more advanced energy harvesting technologies has been increased more than ever. As a promising energy harvesting technology, the piezoelectric energy harvesting technology has been developed in many ways to achieve even higher energy-efficiency and more enhanced output performance. In addition, more studies on the piezoelectric devices composed of non-toxic and bio-friendly materials need to be conducted while considering the wearable devices. In this paper, we present a study on various types of piezoelectric devices fabricated by stacking the multilayers of thin films. The piezoelectric devices were all fabricated by an RF magnetron sputtering method, using bio-friendly targets such as ZnO, AlN, SiO2,etc. This fabrication method has an advantage over other methods because it is relatively simple, easy and cost-effective. Particularly for the application of wearable devices as well as various sensors, all the devices were made on a flexible and transparent substrate. To fabricate various piezoelectric devices, we used an RF magnetron sputtering method as well as a thermal annealing process. The device performance was evaluated in terms of output voltages. Also, the micro structures of the deposited thin films were analysed using X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. Acknowledgment: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant No. 2016R1D1A1B01007074).