Fig. 4: Hybrid fabrication strategies for 3D nanoelectronic devices.

a Fabrication of kinked nanowire probes: Using a series of top-down lithography steps, a presynthesized (bottom-up) kinked Si nanowire is integrated into a flexible probe body composed of metal interconnects and a polymer⁵⁸. b Fabrication of IrOx nanotubes: A nanohole template defined by top-down lithography is used to guide the bottom-up electrochemical deposition of IrOx into a tubular structure⁷⁵. c Fabrication of nanotemplate electrodes using a poly(ethylene terephthalate) (PET) template: Using a prefabricated porous PET membrane as a scaffold, combining bottom-up ALD coating with top-down conventional microfabrication affords a vertical electrode array⁷⁶. d Fabrication of nanobranch electrodes: A ZnO seed layer region is defined by top-down lithography, followed by the selective, bottom-up hydrothermal growth of nanobranches in that area⁷⁷