Scanning probe microscopy
Scanning probe microscopy is a branch of microscopy that was founded with the invention of the Scanning tunneling microscope. It is a microscopy technique where a probe only has a significant interaction with a very small volume of the sample specimen. An image of the sample is obtained by mechanically moving the probe with respect to the sample so that the sample is scanned line by line, and recording the probe-sample interaction as a function of position.
Many scanning probe microscopes can image several interactions simultaneously. The manner of using these interactions to obtain an image is generally called a mode. The best established types of microscopes/modes are:
- STM: scanning tunneling microscope
- AFM: atomic force microscope
- MFM: magnetic force microscope
- EFM: electroscatic force microscope
- SCM: scanning capacitance microscope
- NSOM: near-field scanning optical microscope
Advantages of the scanning techniques are:
- The resoution of the microscopes is not limited by diffraction, but only by the size of the probe-sample interaction volume, which can be as small as a few picometres.
- The interaction can be used to modify the sample to create small structures.
Disadvantages of the scanning techniques are:
- The scanning techniques are generally slower in acquiring images, due to the scanning process.
- The maximum image size is generally smaller.