Uniscan Instruments

Uniscan Instruments Ltd, Sigma House, Burlow Road, Buxton SK17 9JB, UK Pierre Gros... 

Figure 7.23 The portable PCS80 potentiostat-galvanostat (Reproduced by permission of Uniscan Instruments).

Fig. 24 Schematic of an experimental setup for LEIS (provided by Uniscan instruments).

I would like to thank Werner Moritz, Ron Armstrong, and Andrea Sabot for their suggestions for improving this chapter. I am also very grateful to Ed Holden (Perkin Elmer), Andrew Hinton (Solartron Analytical), Graham Johnson (Uniscan Instruments), and Timoer Frelink (Eco Chemie) for providing me with up-to-date technical information. 

The earliest forms of SECM experiments were carried out in the potentiometric mode. Evans reported how he used a traveling reference electrode to map equipotential surfaces in solution and calculate corrosion rates on a water pipeline. Isaacs and coworkers revived the idea in 1972 and coined the acronym SRET for scanning reference electrode technique. Instruments used to be homemade, often with rudimentary traveling devices such as the arm of an X-Y recorder and the spatial resolution was at best submillimeter. A computer-controlled instrument was commercially produced by Uniscan Instruments with a spatial resolution around 20 pm. The SRET has now been superseded by the scanning vibrating electrode technique, known as SVET, which achieves higher spatial resolution and improved sensitivity. A SVET manufactured by Uniscan Instruments is now commercially available from Uniscan Instruments and Princeton Applied Research. 

As SECM instrumentation has been extensively and thoroughly discussed in Chapter 2 of reference (1) and there are also commercial instruments (e.g., CH Instruments, Heka, and Uniscan) on the market, we mainly focus on experimental aspects encountered in imaging and tip positioning with SECM. Readers who are interested in the design of an SECM instrument can refer to that chapter. We also intend to include here an up-to-date account of the newly developed combined techniques so that interested individual investigators may appreciate the design of SECM-related techniques for their specific applications. 

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