The Scanning Electrochemical Microscopy is a four-electrode electrochemical imaging technique. It allows spatial measurement of individual REDOX processes. The working electrode potential, EWE, and the tip potential, Etip, can be tuned independently, with EWE driving the electrochemical system, and Etip monitoring REDOX species in this technique. It uses the scanning electrochemical microscope, which is a scanned probe microscope related to the familiar scanning tunneling and atomic force microscopes. These microscopes are called zoom microscopes. All of the SPM’s operate by scanning or a small probe tip over the surface to be imaged. In SECM, imaging occurs in an electrolyte solution with an electrochemically active tip.
The SECM tip is an ultramicroelectrode and the tip signal is a Faradic current from electrolysis of solution species. Some SECM experiments use an ion selective electrode tip.   There are two features that distinguish SECM from related methods such as electrochemical STM or AFM. This includes the chemical sensitivity of the SECM tip and the use of solution phase ions or molecules as the imaging signal.
Microelectrode Array Microscope
This instrument is a homebuilt instrument. It is based upon the INL SECM. It serves as an alternative to the single microelectrode. This MEA-ECM uses an array of 100 independent microelectrodes that are arranged in a simple 10 by 10 array. The article explains that each of these microelectrodes is controlled and monitored via the Scribner Model 900 MMA. This type of microscope is designed to improve the temporal resolution of the measurement, microelectrode array microscopy. It was developed as a parallel method of performing SECM. It has the potential for analysis of surface chemistry on temporal and spatial domains.
Capillary Microelectrochemical Cell
The system of this operates about a three-electrode design. These are the working electrode, counter electrode, and the reference electrode. The sytem is special because all of its electrolyte volume is contained within a small capillary. This capillary is sealed above a site of interest on the specimen. The article explains that this design allows site selective reaction between the electrolyte and the area of the specimen, which it is in contact. The microelectrochemical cell allows us to seek out localized sites on the surface of a material then position the capillary above an individual site and examine its dissolution.

Digital Instruments Multimode Nanoscope IIIa
The Digital Instruments Nanoscope is referred to as the workhorse SPM. It possesses STM, contact AFM, and Tapping Mode AFM. With the system, experiments can be set up in ambient air, solution, and inert atmospheres. The new instrument is believed to be much easier to use than the MI and it has a larger scan range of 125 mm. The Digital Instrument Nanoscope IIIa multimode scannning probe microscope is primarily used to obtain topographical information on nanostructures, nanodevices, and quantum dots. Also, they are used in thin films, geological and geochemical samples; protein and biomolecule structures at surfaces and samples undergoing electrochemical and corrosion processes. It has the resolution levels that range from the submicron length scale, or nanoscale, to the atomic level. This powerful instrument allows the user to obtain surface roughness statistics, image small nanosized structures, and even image individual atoms on a surface. Read more on this article