Molecular Nanotechnology

How are samples prepared to be viewed by a scanning electron microscope?
Answered by HowStuffWorks
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  1. Since scanning electron microscopes (SEMs) rely on electric fields to create an image, the sample has to be prepared specifically for that process. It must be cleaned of any dirt or dust that could interfere with the electron beams. A sample must be made electronically conductive if it is not naturally so; this involves coating it in a conductive material like gold or platinum. During the coating process, the sample is also grounded so it doesn't get damaged by the electron beam. Because the sample chamber is subject to a vacuum, some materials need additional preparation; for example, biological samples are often dehydrated before being placed in the sample chamber. Otherwise, the vacuum conditions in the sample chamber would destroy the sample before an image could be taken. Other samples may need to be frozen or chemically treated.

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