Through-hole AAO-SA templates with a small pore diameter prepared by the voltage pulse detachment method

A voltage pulse detachment method is a fast and simple alternative for the preparation of nanoporous anodic aluminum oxide (AAO) templates. Free-standing through-hole porous anodic aluminum oxide membranes were fabricated by a two-step self-organized anodization of aluminum in a sulfuric acid (SA) solution followed by a voltage pulse detachment process in a mixture of HClO4 and C2H5OH (1:1 vol). In this work, the influence of height, time and number of the voltage pulses, time and conditions of sample storage, and the thickness of oxide layer on the measured current density, bottom-side morphology of the AAO-SA membrane, pore diameter, and overall detachment effect were examined in detail for the first time. The pore diameter of the AAO-SA membranes was estimated from FE-SEM images. It was found that the maximum current density, measured during the voltage detachment process, is the most strongly affected by the conditions and time of sample storage and the AAO thickness. The number of applied pulses and pulse duration influence the most significantly the pore diameter at the bottom side. The as detached AAO membranes with the pore diameter of ca. 20 nm were used as templates for electrodeposition of Au nanowire arrays.