Figure 1
From: Fabrication of Porous Anodic Alumina with Ultrasmall Nanopores
AFM images of ultrasmall nanopores fabricated under 15°C and 2 V for 30 min in 0.3 M oxalic acid: a surface, b 3D image and c height profile by combining the x- and y- axis in (b). AFM images of ultrasmall nanopores prepared in the mixture of 20 wt% H2SO4, 1 wt% citric acid and 1 wt% Al2(SO4)3 under 15°C and 10 V for 30 min: d as-prepared barrier layer, e immersed in 5 wt% H3PO4 for 10 min. f The barrier layer AFM image of PAA anodized in 0.3 M oxalic acid for 30 min under 1 V and immersed in 5 wt% H3PO4 for 6 min. The area of the AFM image in (a) is 1 μm × 1 μm, and the area of other images is 500 nm × 500 nm