Inorganic and Structural Chemistry Assignment March 2021 You are required to write a 3-5 page essay on Transmission Electron Microscopy (TEM). In this essay, you need to cover the following topics: 1....

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Transmission Electron Microscopy (TEM):
An Overview:
Transmission electron microscopy(TEM), is a technique where a beam of electrons is transmitted through a specimen or an object to form an image. This is a very powerful electron microscope which uses electron beams to form a detailed and magnified image. The magnifying power is almost two million times better than a normal light microscope. The detailed image that is formed is focused on the imaging device like a fluorescent screen or a layer of photographic film. TEM uses the principle of producing images using electron beams at a significantly higher resolution. This type of microscopy is a boon for analytical use in the study of science in all aspects as they enable us to see and study about the minutest feature of a specimen. TEM is very popular in the field of cancer research, virology, pollution studies, nanotechnology and other fields of material science as such.
(Refer https://www.sciencedirect.com/topics/materials-science/transmission-electron-microscopy)
Operations of Transmission Electron Microscope:
As we have seen that the TEM works on the principle of using a beam of electrons to form magnified and detailed images of a specimen so it is primarily made up of four parts namely the electron source, electromagnetic lens system, sample holder, and imaging system. The device works like a slide projector where the projects helps the beam of light to shine and transmit through the slide to form the magnified image. There are patterns on the slide which only allows certain portion of the beam to pass through it to form the enlarged image of the specimen on the screen.
A typical TEM has several components to it which mainly comprises of the vacuum system, to enable travelling of the electrons, source of emission of the electron beam, detectors and the electromagnetic lenses and also the electrostatic plates.
If we talk about the basic modes of operation of the TEM, then it uses two modes of imaging which are the bright field mode and the dark field mode. In the former the (000) beam is used to form the image and in the later the (000) is not used in formation of the image. In the case of the bright field modes the size of the objective aperture is responsible to determine the information that is to be used up to form the final image. Among the two modes the bright field mode is the...