Figure 4From: Ordered arrays of nanoporous silicon nanopillars and silicon nanopillars with nanoporous shellsSEM images of nanopillars formed from the lightly doped Si after 10-min etching. In (a, b) λ1, (c, d) λ2, (e, f) λ3, and (g, h) λ4 solutions. Panels b, d, f, and h show the cracked nanopillars. These cracks were formed during the breaking of the samples for the SEM investigations.Back to article page