Electrochemical Characterization of Electrodes with Submicrometer Dimensions

摘要

Arrays of voltammetric electrodes with submicrometer dimensions have been constructed on a silicon substrate using electron beam lithography. The electrode assembly contained over 1 million active electrodes on 1sq cm area of the silicon wafer. Each individual member of the array was a disk with radius 0.375 micrometers. The capacitance and voltammetric characteristics for Cr and Au electrodes in this format are presented and discussed in detail. The impedance behavior of the chromium matrix electrode in the active-passive region has been examined. The average single-electrode characteristics are similar to those obtained for large electrodes. The diffusional impedance of the gold matrix electrode in a solution containing the cupri-cuprochloride couple has also been investigated in order to characterize the interaction of the ac and dc diffusion layers. Good agreement between the experimental results and theoretical predictions was observed. In particular, the imaginary component of diffusional impedance is diminished at lower frequencies and this effect is more pronounced, the smaller the electrode radius.