Simulating Imaging with the Scanning Ion-Conductance Microscope

The scanning ion-conductance microscope (SICM) is a member of the family of scanned probe microscopes (SPM). Examples include the scanning electrochemical microscope (SECM) and atomic force microscope (AFM). SICM uses the ion-concentration field at the tip of a micropipette filled with an electrolyte solution as a probe to generate images of sample topography. As with other members of the SPM family, the probe geometry determines the observed image. This paper presents mathematical models for simulating the SlCM in its different operating modes with the intent of creating a framework within which the effect of probe-geometry can be studied. We validate our model by comparing simulated approach-curves with empirical data. Finally, we show simulated images of a Gaussian-bump substrate under the different operating modes of the SICM