Figure 4From: Fabrication of Porous Anodic Alumina with Ultrasmall NanoporesAFM images with an area of 250 nm × 250 nm of PAAs fabricated under a 2 V for 5 s, b 2 V for 20 s and c 10 V for 10 s in 0.3 M oxalic acid, AFM images with an area of 500 nm × 500 nm under d 15 V, e 20 V and f 35 V for 10 s in 0.3 M oxalic acid, respectivelyBack to article page