Scanningprobe

Scanningprobe refers to a family of microscopy techniques collectively known as scanning probe microscopy (SPM). In these methods, a sharp probe or tip scans close to a sample surface while a local interaction between the tip and the surface is measured. The recorded signal is used to construct maps of surface topography or other properties with nanoscale or atomic resolution. The approach is versatile, working in air, liquids, or vacuum, and can provide mechanical, electrical, magnetic, or optical information.

A typical scanning probe instrument consists of a sharp tip attached to a flexible cantilever, a piezoelectric scanner to move the tip in three dimensions, and a detector that senses tip deflection or other interaction signals. A feedback loop maintains a constant interaction by adjusting the tip-to-surface distance as the tip scans, producing a two-dimensional image. In some variants, the tip remains at a fixed height while other signals are modulated, revealing electronic or magnetic properties.

The most well-known SPM modalities are scanning tunneling microscopy (STM) and atomic force microscopy (AFM). STM measures tunneling current between a conductive tip and surface under a bias, offering atomic-scale topography for conductive samples. AFM senses forces between the tip and surface and works on insulating materials as well, providing high-resolution height data and, with specialized modes, mechanical, electrical, or chemical information. Other variants include magnetic force microscopy (MFM), electrostatic force microscopy (EFM), and near-field optical techniques such as SNOM.

SPM has applications across materials science, nanotechnology, semiconductor research, and biology, enabling characterization of surfaces, thin films, nanostructures, and molecular interactions with minimal sample preparation. It emerged in the 1980s, with STM pioneered by Gerd Binnig and Heinrich Rohrer, followed by AFM development by Binnig and collaborators, greatly impacting nanoscale science.