Figure 5

Scanning electron microscope images of silicon moulds fabricated using the cryo-etch process. Standard processing of (a) micro- and (b) nanosized trenches with a distance between nanostructures of 330 nm and the resulting difference etch rates. Double etching process on (c) micro and (d) nanosized structures (d=2 μm) resulting in trenches with equivalent depths. (e) Junction between micro- and nanostructures (pitch 400 nm). (f) Hierarchical structures featuring nanochannels (d=400 nm) etched next to and at the bottom of a microchannel.