Fabrication of Cu nanowires along atomic step edge lines on Si(1 1 1) substrates

We have succeeded in the fabrication of high-aspect-ratio (length to width) Cu nanowires along atomic step edge lines on Si(111) substrates. The fabrication procedure consisted of two wet process steps: (1) flattening of the surface roughness to an atomic level by immersing Si(111) wafers in ultralow-dissolved-oxygen water (LOW), and (2) Cu nanowire formation by immersion in LOW containing 10ppm Cu ions for 1s at room temperature. On the other hand, no Cu nanowires were formed on the Si(111) surfaces when the dissolved oxygen content was 8ppm in alkaline solution during the Cu deposition stage, even though the Si etching with OH ^- was enhanced. We consider that it is due to the decrease in reduced Cu atom density by the existence of the dissolved oxygen as superoxide anion radicals.