HEM | About Scanning Electron Microscopy (SEM)
Posted on July 30, 2010 by max
Not far from the birth of the TEM, SEM was developed in 1938 by Manfred von Ardenne (German scientists). The basic concept of the SEM has been made by Max Knoll (inventor TEM) in 1935. He worked on the principle of the electron beam scans the sample surface and then the information obtained has been changed to the images.
The path to the SEM image of the shape is different from what happened in the light microscope and TEM. In SEM, the statue was based on the detection of new electrons (secondary electrons), or on behalf of electrons from the surface of the sample if the sample surface is scanned by an electron beam.
After the secondary electrons or reflected electrons have also been identified, we amplified and the amplitude are shown on the display of light and dark tones in the CRT (Cathode Ray Tube). In the CRT, an image of the object structure has been enlarged view. As part of the operation, the SEM does not require that the sample was diluted so that could be used to display objects from the three-dimensional perspective.
Thus, the SEM has high resolution and familiar to the nano-sized objects eight meters. However, high-resolution for scanning in the horizontal direction, while the vertical scan is low resolution. This has been the weakness of the SEM that there was no solution.
However, since around 1970, has developed a new microscope. This new high-resolution microscope has both horizontal and vertical scanning microscopy known as probe (SPM). MPS had a working principle that is different from the SEM and TEM. It was a new generation of this type of scanning microscope.
Microscopes now known that this type scanning tunneling microscope (STM), atomic force microscope microscope (AFM) and scanning near field optical (SNOM). This type of microscope is widely used in nanotechnology research.
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