How to choose a microscope that suits your needs?
In the field of scientific research and analytical testing, microscopes are undoubtedly indispensable tools and are known as the "eye of science". It enables humans to explore the microscopic world that cannot be distinguished by the naked eye, providing key technological support for fields such as materials research, biomedicine, and industrial testing. Faced with different research needs, how to choose the appropriate microscope has become a concern for many researchers.
This microscope uses a high-pressure electron beam as a light source and focuses imaging through an electromagnetic lens. Its magnification can reach millions of times, and its resolution can even reach the level of angstroms (Å) (1 Å equals 0.1 nanometers), which is sufficient to observe atomic level structural features.
The working principle of transmission electron microscopy is similar to that of optical microscopy, but it uses electron beams instead of visible light and electromagnetic lenses instead of optical lenses. Due to the fact that electronic waves are far smaller than the wavelength of visible light, according to the Abbe diffraction limit theory, their resolution has been greatly improved, achieving the ultimate exploration of the microscopic world.
Modern transmission electron microscopy technology has developed rapidly, giving rise to various advanced models: scanning transmission electron microscopy (STEM) combines the advantages of both scanning and transmission modes; Ultra fast transmission electron microscopy (UTEM) can be used to study ultrafast dynamic processes; Frozen transmission electron microscopy (FTEM) is particularly suitable for the study of biomolecules; In situ transmission electron microscopy (TEM) can observe real-time changes in samples under external stimuli; Spherical aberration correction transmission electron microscopy (CTEM) further improves resolution by correcting lens aberrations.
It should be noted that transmission electron microscopy, as a high-precision instrument, has the characteristics of high cost, complex operation, and strict sample preparation requirements. The sample must be prepared into extremely thin (usually less than 100 nanometers) slices to allow electron beam penetration.
scanning electron microscope
If the research scale is in the range of tens of nanometers to millimeters and mainly focuses on the surface morphology characteristics of the sample, scanning electron microscopy (SEM) is a more suitable choice. This microscope has a wide magnification range (usually from 10x to 300000 times), which can meet most of the needs for morphology observation, elemental analysis, microstructure analysis, and so on.
The working principle of scanning electron microscopy is to scan the sample surface point by point with an electron beam, and then detect signals such as secondary electrons and backscattered electrons generated by the sample to form an image
