Application Overview Halcyonics Products: Scanning Probe Microscope - SPM

AFM is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. An image is obtained by mechanically moving the probe in a raster line by line (probe-surface interaction as a function of position)

• can be operated in a number of modes, depending on the application
• possible imaging modes are divided into static (contact) modes and a variety of dynamic (non-contact) modes where the cantilever is vibrated

The STM is based on the concept of quantum tunneling. When a conducting tip is brought very near to the surface to be examined, a bias (voltage difference) applied between the two can allow electrons to tunnel through the vacuum between them. The resulting tunneling current is a function of tip position, applied voltage, and the local density of states (LDOS) of the sample. Information is acquired by monitoring the current as the tip's position scans across the surface, and is usually displayed in image form.

Scanning Hall probe microscope (SHPM) is a variety of a scanning probe microscope which incorporates accurate sample approach and positioning of the scanning tunnelling microscope with a semiconductor Hall sensor. This combination allows to map the magnetic induction associated with a sample.

Scanning electrochemical microscopy: The structures of surfaces and electrochemical reactions in solid-liquid interfaces can be observed at atomic or molecular scales, e.g. with the electrochemical scanning tunneling microscope, or ESTM. On the electrode surface, many atoms, molecules, and ions adsorb and affect the reactions.

Near-field scanning optical microscopy (NSOM/SNOM) is a microscopic technique for nanostructure investigation that breaks the far field resolution limit by exploiting the properties of evanescent waves. This is done by placing the detector very close (distance much smaller than wavelength λ) to the specimen surface. This allows for the surface inspection with high spatial, spectral and temporal resolving power. With this technique, the resolution of the image is limited by the size of the detector aperture and not by the wavelength of the illuminating light. In particular, lateral resolution of 20 nm and vertical resolution of 2–5 nm have been demonstrated As in optical microscopy, the contrast mechanism can be easily adapted to study different properties, such as refractive index, chemical structure and local stress. Dynamic properties can also be studied at a sub-wavelength scale using this technique.