Oxidative fabrication of patterned, large, non-flaking CuO nanowire arrays

We report a simple and fast approach to fabricate large, non-flaking arrays of CuO nanowires by oxidizing thin copper substrates in air. Oxidative CuO nanowire growth is commonly accompanied by oxide layer flaking due to stress at the copper-copper oxide interface. Using thin substrates is shown to prevent this flaking by introducing favourable material thickness ratios in the samples after oxidation. Additionally, thin foils allow larger scale topographic patterns to be transferred from an underlying mould to realize non-flat, nanowire-decorated surfaces. Further patterning is possible by electrodeposition of a nickel layer, which restricts nanowire growth to specific areas of the sample.