Representative EFDP-generated topological overview. Cross-section
AFM profiles, top-view OM images, SEM micrographs, and DNN images
of the EFDP generated structures. Corresponding SERS enhancements
are shown in Figure 3d. (a) Pillar with Hrim = 250 nm and
a nanoroughened center, EF = 9.0 × 106. (b) Pillar
with an equivalent nanorim of Hrim = 300
nm and a roughened center, EF = 1.1 × 107. (c) Pillar
with a one-sided nanorim of Hrim = 270
nm and a roughened center, EF = 8.8 × 106. (d) Pillar
with nanoroughness throughout and no rim, EF = 6.4 × 106. (e) Smooth pillar with one-sided nanorim of Hrim = 200 nm, EF = 6.1 × 106. (f) Pillar with
a nanorim of Hrim = 150 nm, EF = 6.7 ×
106. (g) Smooth pillar top with no rim, EF = 5.8 ×
106. Scale bar SEM: 1 μm.