Fabrication of copper nanowires via electrodeposition in anodic aluminum oxide templates formed by combined hard anodizing and electrochemical barrier layer thinning

摘要

AbstractAnodic aluminum oxide was formed by employing mild and hard anodizing in sulfuric acid followed by mild anodizing in oxalic acid without oxide removal in-between at 40 and 45V. Such multi-step anodizing, combining hard anodizing in sulfuric acid with mild anodizing in oxalic acid allowed to form a highly-ordered nanoporous template with a barrier layer at the pore bottoms thin enough for further processing. Four different conditions of electrochemical barrier layer thinning, with varied voltage steps and their time durations, were investigated. Optimized conditions allowed to provide conductivity at the pore bottoms and made the nanoporous oxide templates suitable for electrodeposition. It was found that the most effective barrier layer thinning approach employs voltage steps Un+1=0.75·Unwith each step (n) being 10s long. To check applicability of the formed templates, copper electrodeposition from sulfate-borate bath was done. Copper nanowires with average length of about 14–16μm and diameter of about 35–40nm were obtained by using through-hole AAO templates.Graphical abstractDisplay Omitted展开▼