Figure 1.

SEM images of pCuFEs prepared using colloidal crystal templating with 500 nm polystyrene spheres, constant current of –1.5 mA, and various times of copper electrodeposition from 0.1 mol L⁻¹ Cu(II) in 0.01 mol L⁻¹ HNO₃ (pH 2): (a) 30 s; (b) 60 s; (c) 90 s; (d) non-porous Cu film formed without colloidal crystal template after 90 s electrodeposition for comparison (magnification 3000×, scale bar 5 µm). Insets are a lower magnification (1000×, scale bar 10 µm) of corresponding electrode surfaces.