Finite element method calculations of ZnO nanowires for nanogenerators

The bending of a nonconducting piezoelectric ZnO nanowire is simulated by finite element method calculations. The top part is bent by a lateral force, which could be applied by an atomic force microscope tip. The generated electrical potential is +/- 0.3 V. This relatively high signal is, however, difficult to measure due to the low capacitance of the ZnO nanowire (similar to 4x10(-5) pF) as compared to the capacitance of most preamplifiers (similar to 5 pF). A further problem arises from the semiconducting properties of experimentally fabricated ZnO nanowires which causes the disappearance of the voltage signal within picoseconds. (C) 2008 American Institute of Physics.