Development of magnetically driven contactless piezoelectric nanogenerators utilizing ZnO nanowires with different shaped top electrodes

In this research, ZnO nanorod (NR)-based contactless piezoelectric nanogenerators (C-PENGs) with pyramidal and zigzag-shaped top electrodes were fabricated. ZnO NRs with different aspect ratios were grown on a Si (100) wafer, which acts as the bottom electrode. Two different top electrode architectures, zigzag-trenched and pyramidal cavity, were used. Additionally, different work function metallic coatings, platinum and nickel (as a cheaper alternative to noble metals) were applied to the architecturally shaped surfaces to achieve a Schottky contact between the top and bottom electrodes. A magnetic field ranging from 3.5 Oe to 55 Oe with a frequency range between 0.5 and 2 Hz was applied to drive the nanogenerator. The results showed that a maximum output voltage of 75 mV and a maximum power density of 20.7 pW cm⁻² were successfully generated. The measurement of output power densities revealed that C-PENGs are a promising candidate for future nanorobotics applications.