ZnO nanorods array/BaTiO3 coating layer composite structure nanogenerator

In this study, we fabricate a nanogenerator device based on a composite structure formed by ZnO nanorods array/BaTiO3 coating layer for harvesting mechanical energy from environment. The whole device is composed of a Si substrate, a ZnO nanorods array, a BaTiO3 coating layer and a top Cu foil electrode. The ZnO nanorods were grown by a hydrothermal synthesis technique and the BaTiO3 thin layer was coated on the surface of the ZnO nanorods by rf magnetron sputtering process. It is a simple and low-cost growth method to make the ZnO nanorods array act as a template to increase the area of the subsequently deposited BaTiO3 layer. The device produced an enhanced average current of 105 nA, which was 7 times larger than the devices with only piezoelectric ZnO nanorods array and 3.5 times larger than the devices with only piezoelectric BaTiO3 thin film, respectively. The possible reasons contributing to the enhancement of the output current were discussed.