Sensor Technology for Scanning Probe Microscopy

The invention of the scanning tunneling microscopy (STM) by Binnig and Rohrer [1–3] and the atomic force microscopy (AFM) by Binnig et al. [4] has unleashed the development of a new class of analytical tools that revolutionized surface science during the last two decades. The capability to study various surface properties on an atomic scale [5] coupled with the capability to manipulate or arrange molecular structures [6, 7] has blossomed into what recently is denoted

nanoscience technology

. The heart of any scanning probe microscope tool is certainly the sensing element simply termed “probe”. It consists in almost all cases of a sharpened tip with extremely small radius ofcurvature that determines the interaction volume with the local sample surface and thus the lateral resolution during the scanning process. We will concentrate in this report only on AFM-based probes, that is, cantilever probes consisting of a mechanical beam with an integrated sharp tip, because they have proven to be the most flexible arrangement for future developments in SPM. Details on the various AFM operation modes and their operation limits are not within the scope of this report and may be found elsewhere (8–11] and references therein). The same holds for the various forces involved in that process (e.g., see refs. [12–15]).