Enhanced charge generation of the ZnO nanowires/PZT hetero-junction based nanogenerator

We fabricated an alternative nanogenerator device with distinguished structure. Representative piezoelectric materials of ZnO nanowires and PZT thin films were tried to be combined to form a hetero-junction structure for fabrication of an alternative nanogenerator device to possibly obtain a synergy effect and then improved performance. The ZnO nanowires were grown by a hydrothermal synthesis technique and then PZT thin films were deposited on the surface of the ZnO nanowires by rf magnetron sputtering process. The PZT thin films were annealed to be crystallized with different conditions for post-deposition thermal treatment process. The hetero-junction structure was polarized by a Corona poling process to obtain a unidirectional orientation of dipole moments to enhance their piezoelectric property. Structure and morphology of the grown ZnO nanowires were investigated to achieve appropriate characteristics to achieve performance improvement for the resulting nanogenerator device. To confirm effect of the hetero-junction structure on improvement of power generation performance of the resulting nanogenerator device, current generating properties were comparatively investigated with those of nanogenerator device with only ZnO nanowires or PZT thin films as active piezoelectric component, respectively. The nanogenerator device with a hetero-junction structure of ZnO nanowires/PZT revealed distinctively improved average currents of 270 nm, which is quite higher than those of the nanogenerator devices with pristine ZnO nanowires, or with pristine PZT thin films, respectively. Possible factors contributed to improvement of the current generation properties were discussed for the presented nanogenerator device.