In 1981 Binnig et al. invented the scanning tunneling microscope (STM)1, which enables a (semi)conducting surface to be imaged with atomic resolution. Based on this first scanning probe microscope (SPM) and driven by the wish to also image non-conductive surfaces, Binnig et al. went on to invented the Atomic Force Microscope (AFM) in 19862. A variety of other SPMs have since been developed, such as the Electrochemical STM (EC-STM), the scanning near-field optical microscope (SNOM), the scanning ion-conductance microscope the scanning capacitance microscope and the magnetic force microscope.7 H.J. Hug et al., Rev. Sci. Instrum. 64 (1993), p. 2920. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (28
The principle of all SPMs is probing the interaction between the sample surface and a sharp tip while either of them is scanned laterally in the area of interest. In the STM this tip–sample interaction is the tunneling current, whereas in the AFM it is the forces acting between the tip and the sample surface. For most SPM modes this tip–sample interaction is held constant by a feedback loop that varies the vertical (Z) position between the sample and the tip in order to compensate for variations in the tip–sample interaction, such as those induced by the sample topography during the scanning process.
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