On-chip suspended gold nanowire electrode with a rough surface : fabrication and electrochemical properties

Abstract

Nanoporous materials have attracted great attention due to the large ratio of surface over volume. Similarly, nanomaterials with big surface roughness have also high surface/volume ratio. The present work investigates the electrochemical behavior of a nanowire electrode with a big surface roughness. An on-chip individually addressable suspended gold nanowire (width: 340 nm, thickness: 90 nm, and length: 5.5 μm) electrode with an arithmetic mean surface roughness of 15.02 ± 2.95 nm was fabricated by using the electron beam lithography and reactive ion etching technique. The Cyclic Voltammograms (CV) of the suspended Au nanowire electrode in both the potassium ferricyanide and the sulfuric acid electrolytes show noticeably different characteristics from that of the control Au thin film electrode. The suspended nanowire shows an excellent room-temperature cyclic reliability, with only ±3% variation in the integrated capacitance after 600 cycles at the scanning rate of 0.1 Vs-1. The facile on-chip fabrication, large effective surface area, and excellent cyclic stability make the suspended gold nanowire electrode an ideal candidate for many emerging applications such as electrochemical catalysts, biosensors, and detectors.