Fig. 6

I Overview of the nanoimprint process for the fabrication of gold nanofingers showing a patterning of pillars and etching into Si master mold, b first imprint transferring pattern to daughter mold, c second imprint creating d original pillar pattern, e evaporation of Au metal to form particles on pillar tips and f collapsing of pillars into the designed geometries. g SEM images of a representative set of particle arrangements fabricated using this technique. Scale bar is 200 nm [67]. II Sequence of SEM images showing a Si cones fabricated by a Bosch etch process, b replicated in a polymer by nanoimprint lithography while maintaining sharp tips as required for optimal SERS performance and c coated with gold [61]. III a Top and sideview images of a multilayer 3D negative index material fabricated by nanoimprint lithography on both b a rigid and c flexible substrate [70]