Performance enhanced piezoelectric ZnO nanogenerators with highly rough Au electrode surfaces on ZnO submicrorod arrays

Zinc oxide (ZnO) nanorod arrays (NRAs)-based piezoelectric nanogenerators (NGs) with highly rough gold (Au) film as a top electrode were fabricated by a simple electrochemical deposition. The Au was evaporated mainly onto the discrete top surface of ZnO submicrorod arrays (SMRAs), creating a highly rough Au electrode surface. By applying a pushing force to the ZnO NG, the output current density was increased by ∼1.54 times compared with the Au top electrode deposited without ZnO SMRAs because the larger bending radius of ZnO NRAs leads to increased contribution to the overall piezoelectric charge output due to the roughened top electrode.