Enhanced piezoelectric performance of the ZnO/AlN stacked nanofilm nanogenerator grown by atomic layer deposition

The ZnO-based nanogenerators (NGs) with a precisely controlled interlayer of AlN are fabricated based on atomic layer deposition technique, which was proved to possess an enhanced output signal. The microstructure and composition profiles of the prepared ZnO/AlN stack layer are well characterized first. It was found that the piezoelectric performance of ZnO/AlN stacked nanofilm NGs depends strongly on the thickness of AlN. The maximum piezoelectric open circuit output voltage of 4.0 V and output power of 2.42 µW have been achieved with an optimum 2.3 nm thick AlN interlayer. The piezoelectric output of the NGs also relates with the value and the frequency of the compressive force. The inherent mechanism for the improvement of piezoelectric performance in the stacked structure is well discussed. The findings are expected to provide a simple, inexpensive, and effective approach for enhancing the performance of ZnO-based NGs.