Piezoelectric effect of 3-D ZnO nanotetrapods
In this work the piezoelectric effect of 3-D ZnO nanotetrapods (ZNTs) is studied by the finite element method. The results show that the nanogenerator based on ZnO nanotetrapods has a number of advantages over the generators based on traditional hexagonal nanorods due to the unique tetrapod structure. Different from double-terminal sensors, the sensors based on ZnO nanotetrapods can give multiple responses to a single signal at the same time. Therefore, ZnO nanotetrapods could be designed as multiterminal strain sensors for enhancing sensitivity and directivity. Here we demonstrate that lateral bending of ZnO nanotetrapods (ZNTs) results in higher output piezopotentials than vertical compression. Effect of geometric size on piezopotential is also studied. The results provide guidance for optimizing the output of piezoelectric nanogenerators and designing high-performance strain sensors.