Hand-Fabricated SECM-AFM Probes

The first documented SECM-AFM probe is described in [6], fabricated from a 50 pm diameter Pt wire. In the arena of nanoscopic electrode fabrication [7] and the production of tips for electrochemical STM [8], procedures are well established for the electrochemical etching and insulation of microwires, to produce sharpened and insulated, except at the very apex of the tip, nanoelectrodes. In the AFM field, solid metal AFM probes, for the measurement of the electrical, frictional, and topographical properties of a substrate, have been fabricated previously, by hand, from metal microwires [9]. Thus, by combining the two methodologies together, it was possible to fabricate SECM-AFM probes. 

FIGURE 17.1 (a) Micrograph of a coated SECM-AFM probe. Scanning electron micrographs of the end 

3 Use of Commercially Available AFM Probes for SECM-AFM Probe Development 

For more widespread application of SECM-AFM, there is a need for probes with reproducible and defined characteristics, and microfabrication technologies represent an attractive way forward. Two approaches currently exist (1) modification of an existing commercial AFM probe in order to build in electrochemical functionality and (2) bottom-up fabrication, where the probe structure is built from first principles. This section will deal with the former, while Section 17.1.4 discusses the latter. 

FIGURE 17.3 Focused ion beam image of an integrated frame submicroelectrode with an edge length of 800nm and a tip height of 300 nm. (Unpublished data.) 

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