Fabrication and AFM investigation of the temperature-dependent surface morphology of Au (100) single crystal ultramicroelectrodes.

A previously reported method for preparation of gold (111) single-crystal utramicroelectrodes (scumes) has been used to fabricate gold (100) scumes with effective diameters from 20 to 50 microm. Cyclic voltammograms for these ultramicroelectrodes obtained in perchloric acid show similar features to gold (100) single-crystal electrodes of more conventional sizes, but with differences that are a result of different surface preparation methods used before the measurement. The gold crystals used to prepare Au (100) scumes were grown at room temperature so that the cyclic voltammetric characteristics reflect the unique properties of a room temperature-ordered surface. The AFM images of the (100) facets of these crystals are also presented. The effects of annealing Au (100) at 800 degrees C for a short time were studied both electrochemically and using AFM and are discussed with respect to the data obtained for crystals grown at room temperature.