Anisotropic outputs of a nanogenerator from oblique-aligned ZnO nanowire arrays.

We studied the dependence of the output of the piezoelectric nanogenerator (NG) on the inclining orientation of the ZnO nanowire arrays (NWAs). The oblique-aligned NWAs were grown by combing a modified oblique-angle sputtering technique for preparing the seed layer and hydrothermal growth. The piezoelectric output of the NWAs was studied by scanning the tip of an atomic force microscope along four different directions in reference to the inclining direction of the NWs. The statistical outputs were analyzed in reference to the theoretically calculated piezopotential distribution in the NWs. Our study provides in-depth understanding about the performance of NGs.