A Control of the Nanopore Regularity in Alumina Layer

This study placed a focus on fabrication factors and surface morphology characteristics to obtain anodic alumina layers with ordered nanopore arrays using two-step anodization process. The regularity of nanopore arrangement in anodic alumina was prepared in oxalic acid at 40 V. The regular array was shown to be more strongly dependent on the time of first anodization than that of second anodization. The widening process of oxide surface in H3PO4 solution clearly exhibits that the nanopore diameter of the alumina layer subjected to widening time increased linearly at a rate of 0.6 nm/min at 30°C, and 0.8 nm/min at 40°C. The pore arrays in anodic alumina were analyzed by SEM.