Fig. 1.
Design for converting nanoscale mechanical energy into electrical energy by a vertical piezoelectric ZnO NW-based PENG. a SEM images of aligned ZnO NWs grown on α-Al2O3 substrate. b TEM images of ZnO NWs, showing the typical structure of the NW without an Au particle or with a small Au particle at the top (inset at center shows SAED pattern). c Experimental setup and procedures for generating electricity by deforming a piezoelectric NW with a conductive AFM tip. d Potential distribution for a ZnO NW in side view. e Electric signal collected by AFM on a ZnO NW array. Figures adapted from [10, 46]