Integrating an ultramicroelectrode in an AFM cantilever: combined technology for enhanced information

We present a novel approach to develop and process a microelectrode integrated in a standard AFM tip. The presented fabrication process allows the integration of an electroactive area at an exactly defined distance above of the end of a scanning probe tip and the subsequent remodeling and sharpening of the original AFM tip using a focused ion beam (FIB) technique (See ref 1 for patent information). Thus, the functionality of scanning electrochemical microscopy (SECM) can be integrated into any standard atomic force microscope (AFM). With the demonstrated approach, a precisely defined and constant distance between the microelectrode and the sample surface can be obtained, alternatively to the indirect determination of this distance usually applied in SECM experiments. Hence, a complete separation of the topographical information and the electrochemical signal is possible. The presented technique is a significant step toward electrochemical imaging with submicrometer electrodes as demonstrated by the development of the first integrated frame submicroelectrode.