Integrated Multilayer Nanogenerator Fabricated Using Paired Nanotip-to-Nanowire Brushes

We present a new approach to a nanogenerator (NG) that is composed of integrated, paired nanobrushes made of pyramid-shaped metal coated on nanotip (NTP) arrays and hexagonal-prism-shaped ZnO nanowire (NW) arrays, which were synthesized using a chemical approach at $<$100 \r{ }C on the two surfaces of a common substrate, respectively. With one piece of such a structure stacked in close proximity over another to form a layer-by-layer matched brush architecture, direct current is generated by exciting the architecture using ultrasonic waves. A four-layer integrated NG is demonstrated to generate an output power density of 0.11 \textit{$\mu $}W/cm2 at 62 mV. The layer-by-layer assembly provides a feasible technology for building three dimensional NGs for applications where force or pressure variations are available.