Development of Thin Film Electrodes Based on Sputtered Amorphous Carbon

Abstract
The fabrication of a novel thin film electrode based on radio frequency (RF) magnetron sputtered carbon 10 to 500 nm thick is reported. To minimize problems arising from the ohmic resistance of carbon thin films, a titanium nitride base layer is sputter‐deposited onto a silicon substrate. This carbon thin film electrode (CTE) compares very favorably with conventional carbon electrodes such as glassy carbon. The CTE exhibits a low double‐layer capacitance, a large electrochemical window, and a relatively high activity toward ferricyanide reduction. The formation of surface functional groups and the resulting pH response is discussed. Due to the smoothness of the surface, the CTE provides an excellent substrate for mercury films. The potentiometric stripping response of the mercury‐coated CTE toward cadmium, lead, and copper ions at the ppb concentration level in nondeoxygenated solutions is studied. Furthermore, a comprehensive evaluation of physicochemical properties of RF magnetron sputtered carbon films is presented.