Fig. 1
Wet etching nanoimprint lithography using the PVA replica mold. a Ellipsometry analysis of TiO2 89 wt% PER. b Schematic of the wet etching NIL process. c–h Scanning electron microscopy (SEM) images of various replicated nanopatterns using PVA replica mold. Nanopillar: c Square array, Diameter (D = 200 nm), Period (P = 400 nm), Height (H = 200 nm), Aspect Ratio (AR, H/D = 1), d Hexagonal array, D = 100 nm, P = 200 nm, H = 200 nm, AR = 2. Densely packed nanocone: e Hexagonal array, D = 300 nm, P = 300 nm, H = 150 nm. Nanoline: f D = 70 nm, P = 140 nm, H = 70 nm, g D = 100 nm, P = 200 nm, H = 100 nm. High aspect ratio pillar: h Square array, D = 500 nm, P = 2 μm, H = 3 μm, AR = 6