What does the transmission electron microscopy method do?
Transmission electron microscopy is more used in material science and biology. Since electrons are easily scattered or absorbed by objects, the penetration is low, and the density and thickness of the sample will affect the final imaging quality, and thinner and ultrathin sections, usually 50-100nm, must be prepared.
Due to the very short wavelength of the electron's de Broglie, transmission electron microscope resolution is much higher than the optical microscope, can reach 0.1 ~ 0.2nm, magnification of tens of thousands to millions of times. As a result, the use of a transmission electron microscope can be used to observe the fine structure of a sample, or even the structure of just a single row of atoms, tens of thousands of times smaller than the smallest structures that can be observed with an optical microscope.
TEM is an important analytical method in many scientific fields related to physics and biology, such as cancer research, virology, materials science, as well as nanotechnology and semiconductor research.
Introduction to the imaging principle of electron microscopy
The imaging principle of electron microscope and optical microscope is basically the same, the difference is that the former uses an electron beam as a light source and an electromagnetic field as a lens. In addition, due to the weak penetration of the electron beam, the specimen used for electron microscopy must be made into an ultra-thin section with a thickness of about 50nm. Such sections are made using an ultramicrotome. The magnification of the electron microscope can be up to nearly a million times, by the illumination system, imaging system, vacuum system, recording system, power supply system consists of five parts, if subdivided: the main part of the electron lens and imaging recording system, placed in a vacuum by the electron gun, condensing mirror, object chamber, objective, diffractive mirror, intermediate mirror, projection mirror, fluorescent screen, and the camera.
An electron microscope is a microscope that uses electrons to visualise the interior or surface of an object. The wavelength of high-speed electrons is shorter than that of visible light (wave-particle duality), and the resolution of a microscope is limited by the wavelength it uses, so the theoretical resolution of an electron microscope (about 0.1 nanometres) is much higher than that of an optical microscope (about 200 nanometres).
