Toward high output-power nanogenerator

In this paper, the factors that determine the power output of a piezoelectric nanowire (NW) nanogenerator (NG) have been analyzed. The output current is the sum of those contributed by all of the NWs while the output voltage is determined by the voltage generated by a single NW, the capacitance of the NW array and the system, and the contact resistance. By growing uniform ZnO NWs with diameters of ∼100nm and lengths of ∼5μm, the output current density and output voltage of the NG was improved to ∼8.3μA∕cm2 and 10mV, respectively, which are 20–30 times higher than that we previously reported. A power generation density of ∼83nW∕cm2 is achieved by using a single layer NW NG.