As we know, in TEM, electrons go through the solids and form images in the screen. the part of the solid where more electrons go through will be more briight, and the part where less electrons go through will be more dark. However, many TEM images of layer composite solids such as metal or metal oxides loaded catalysts show a dark layer with a bright layer on its surface. why is it? suggesting that the route of electron beam is electron gun, loaded species (bright layer image), supporter (dark layer in image), image plane, the final numbers should be decided by the supporter which should result in a dark final image. how electrons form the images of specimen?
A simple reply to the question highlighting the basics together with a link to video is provided as the following.
The Transmission electron microscopy (TEM) is a microscopy technique in which a beam of tiny electrons is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through it.
The TEM imaging works on the de Broglie principle of nature of tiny electrons as they exhibit less wavelength when bombarded with the specimen at a high velocity.
https://youtu.be/sCJxxkeOaGw
Dear Prof. P.K. Karmakar, Thank you very much. I know it is based de Brogile principle. but how the transmitted electrons take image information of specimen?@P. K. Karmakar
Waves carry forward characteristic information of the media they travel through by virtue of their phase properties. Similarly, electronic matter waves carry forward the specimen image information they travel through with the help of their phase aspects. Further microphysical details may be found from the video link provided previously.
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