SPM Principles

SPM (Scanning Probe Microscopy) is a common name for a number of probe microscopies, including Atomic Force Microscopy (AFM), Scanning Tunnel Microscopy (STM), Scanning Near-Field Optical Microscopy (SNOM), etc. The operating principle of SPM in the general case is to scan the surface sample with a tip probe sensor, whose interaction with the surface is short-range.

Scanning is carried out under the control of a controller that maintains a constant level of interaction between the SPM tip and sample during the scanning process. In this case, a change in the value of the scanning control signal of the SPM controller displays the surface topography.

The indicated SPM techniques for mapping the relief are basic, however, during the scanning process, SPM probes can record, in addition to the relief, other characteristics and properties of the surface. These can be nanomechanical, electrical, magnetic and other physical and chemical parameters.

Additional information about the surface under study, in addition to the relief, can also be obtained by local measurements of the dependence of the magnitude of the interaction of the SPM probe with the sample when the SPM probe-sample distance changes. Such SPM techniques are called “Spectroscopy” (STM Spectroscopy, AFM Spectroscopy).

The development of probe microscopy technology gave a powerful impetus to the development of a large group of optical research methods - microscopy and spectroscopy with subwavelength spatial resolution. Overcoming the diffraction limit is realized using optical probes with nano-sized apertures and nano-sized pointed scattering probes.