Impact of Non-Linear Piezoelectricity on the Piezotronic Effect of ZnO Nanowires

ZnO is receiving a considerable attention for the development of novel cost-effective nanostructures with outstanding functional properties for applications in electronics and energy. In this paper, we investigate the effects of the nonlinear piezoelectricity, that has been recently observed in ZnO nanostructures, on the piezotronic effect of ZnO nanowires (NWs). We insert a physically-based model of the nonlinear direct piezoelectric effect into a fully-coupled thermo-mechanical-electric scheme to study the current-voltage characteristic of ZnO NWs under a purely vertical compressive/tensile strain. Our results show for the first time that the nonlinear piezoelectricity deeply affects the current transport processes inside the NW and the behavior of devices for piezoelectric-piezotronic applications and provides remarkable insights into the underlying physics.