Transmission electron microscopy (TEM) is a form of microscopic analysis that transmits a high-energy beam of electrons through an ultrathin sample specimen. This provides imagery based on the transmission/attenuation of electrons, which is then magnified for direct observation and analysis on the micro- and nano-scales. It is a very high-resolution technique for mapping a samples size, shape, and elemental structure in the nanometer size range.
Conventional microscopy is limited by the wavelength of photons used in visible light microscopes which are confined to imaging specimens of several hundred nanometers (nm) and upwards. Transmission electron microscopy allows direct observation of a sample’s structure and morphology at an atomic level, lower than a single nanometer.
This blog post will explore transmission electron microscopy in more detail.
The Working Principles of Transmission Electron Microscopy
Transmission electron microscopy operates using three primary components: an electron source; a series of electromagnetic lenses; and a sensitive optical detector. The high-voltage electron gun directs a beam of accelerated electrons through a condenser aperture, which focuses the beam onto the ultra-thin sample. Transmitted electrons imprint an image based on the distinct optical characteristics of the sample onto a photosensitive screen. This screen then emits photons that are acquired and imaged using a high-resolution camera.
These principles only operate effectively in low vacuum conditions otherwise gas molecules may interfere with the electron beam and cause inconsistencies in the generated micrograph.
Applications of Transmission Electron Microscopy
Transmission electron microscopy is ideal for characterizing materials on the sub-micron scale. It represents the most powerful magnification capacities and the highest possible resolution for microscopic imaging techniques, with a robust range of additional measuring parameters available for distinct applications. Transmission electron microscopy has been coupled with energy-dispersive X-ray spectroscopy (EDS) to accurately determine the elemental composition of samples down to the nanometer scale. It has also been combined with electron energy loss spectroscopy (EELS).
This technique is most commonly used in materials research for biological and physical sciences, with good suitability for assessing the morphology of nanoparticles. It is also an established technique for identifying particulates and residue in pharmaceutical products.
Transmission Electron Microscopy with Jordi Labs
Jordi Labs provides expertise in the field of materials analysis for a broad range of industrial, commercial, and academic applications. We have been enabling researchers with cutting-edge analytical techniques and services since 1980, and we have since become a worldwide authority on how to detect, quantify, and eliminate particulate and residue for manufacturing chains.