Metallic ring-disc microelectrode fabrication using inverted hollow cylindrical sputter coater

A novel method for the fabrication of metallic ring-disc microelectrodes is presented. In this method, an inverted cylindrical sputter coater is used to continuously coat micron sized insulated wires. The cylinder shaped target used in the sputter coater ensures a uniform and symmetrical coating of the wire and its small size improves the deposition rate as well as minimising the cost and waste of the target. Further design features such as the coater's ability to deposit all conducting materials, its small dimensions and ease of assembly are presented. Following the optimisation of the coater's operating parameters, namely the cathode voltage and chamber pressure, the deposition rate achieved for platinum is 1 nm/s. The smallest electrodes produced have outer diameters less than 27 μm and rings as thin as 0.5 μm. The electrochemical measurements made with these Pt/Pt microelectrodes are shown and highlight the quality of the electrodes made and the opportunities that arise from this new fabrication technique.