Simultaneous fabrication of nanogap gold electrodes by electroless gold plating using a common medical liquid

We report a simple and high yield method for fabricating multiple nanogaps simultaneously by an electroless gold plating technique using electroless gold plating solution which consists of common medical liquid of iodine tincture and L(+)-ascorbic acid (vitamin C). The distance between the gold electrodes (33nm in average) on the SiO2∕Si substrate was decreased by selective deposition of gold onto the surface of the gold electrodes. By electroless gold plating, we fabricated nanogaps below 5nm in width with a 41% process yield. We also demonstrated the Coulomb blockade effect in octanethiol(C8)-protected Au nanoparticles by using such a fabricated nanogap.