Scanning probe microscopy
From Free net encyclopedia
Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. An image of the surface is obtained by mechanically moving the probe in a raster scan of the specimen, line by line, and recording the probe-surface interaction as a function of position. SPM was founded with the invention of the scanning tunneling microscope in 1981.
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:
- AFM: atomic force microscope
- EFM: electrostatic force microscope
- FMM: force modulation microscope
- KPFM: kelvin probe force microscope
- MFM: magnetic force microscope
- MRFM: magnetic resonance force microscope
- NSOM: near-field scanning optical microscope
- SCM: scanning capacitance microscope
- SGM: scanning gate microscope
- SNOM: scanning near-field optical microscope
- SThM: scanning thermal microscope
- STM: scanning tunneling microscope
- contact AFM
- non contact AFM
- dynamic contact AFM
- SVM: scanning voltage microscope
Advantages of the scanning techniques are:
- The resolution of the microscopes is not limited by diffraction, but only by the size of the probe-sample interaction volume (i.e., point spread function), which can be as small as a few picometres.
- The interaction can be used to modify the sample to create small structures (nanolithography).
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.
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Programs
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