Transmission electron microscopy (TEM), what is it and what is it for?

Today, characterization techniques are advancing in such a way that they are capable of observing cell organelles in such high quality detail that it looks like a natural science book. In other words, it sounds like science fiction, but it is not, it is a reality. Among all the visualization techniques that have been developed, transmission electron microscopy (TEM) is one of the most powerful. It is capable of observing viruses, lipid bilayers and even the association and distribution of the atoms that make up a material.

At ATRIA, we offer transmission electron microscopy (TEM) to obtain morphological, crystallographic, atomic-structural, chemical composition, electronic structure, and coordination number data from your sample. Contact us!

In today’s post, we will tell you about transmission electron microscopy and its most relevant applications. Don’t miss it!

How the transmission electron microscope (TEM) works

Transmission electron microscopy, or TEM, is a visual technique in which an electron beam is focused on a sample to obtain a magnified image of the sample. It can be understood as a tool specifically designed for the analysis of samples in dimensions from notational microspace and nanospace, characterized by its high lateral spatial resolution (greater than 0.2 nm) and its ability to provide both image and diffraction information from a single sample.

The operation of the TEM could be summarized in the following points:

1. The primary electrons generated by the electron gun are focused at different stages by condenser lenses into beams.
2. The electrons interact with the sample.
3. The electron beam leaves the object and forms the image when it reaches the objective lens.
4. The image is magnified by a projection lens.
5. The passing electrons (transmission) reach the plate of a scintillator located at the base of the microscope column.
6. The scintillator contains phosphor compounds that can absorb the energy of the colliding electrons and convert it into luminous flashes, forming an image.

How a measurement is performed in the transmission electron microscope (TEM)

As we have indicated above, one of the advantages offered by TEM is the possibility of obtaining a spatial resolution greater than 0.2 nm. This means that while with a conventional optical microscope we are able to differentiate and measure the size of bacteria, with TEM we are able to detail bacterial subcellular structures. The difference is abysmal.

TEM is a microscopy technique in which an electron beam is transmitted through a sample, interacting with the sample as it passes through. This means that our main limitation is the preparation of the sample, which must be ultra-thin. TEM materials must be prepared especially with thicknesses between 10 and 200 nm, which allow the transmission of electrons through the sample. In addition to being their thickness, the samples have to meet the following requirements:

• Be electrically conductive
• Vacuum stable
• No hydrocarbon contaminants

TEM applications

The transmission electron microscope (TEM) is a powerful analytical tool that can be used to obtain morphological, crystallographic, atomic-structural, chemical composition, electronic structure and coordination number data of the sample. Thanks to these properties, its application can be in different areas of knowledge such as materials science, geology, environment and biology in general.

Some of the most characteristic examples are the morphological analysis of samples of small organisms such as bacteria or viruses, or the inclusion of samples for subsequent collection and construction of three-dimensional images.

Case study of a TEM application at ATRIA

As we have indicated above, TEM allows us to analyze almost all the properties of materials, from their chemical composition at the nanoscale to the angles of the bonds of their atomic structure.

In ATRIA, we are aware of the potential of TEM as an analytical tool, so one of the resources we offer to our customers when they need to evaluate the quality of one of their products, analyze nanometric defects of the same and want to develop new materials.

Specifically, one of the projects with the greatest impact on ATRIA was the TEM analysis of materials injected with carbon fiber whose mechanical performance began to decrease drastically. After analyzing the sample with TEM, it was observed that the distribution of the carbon fibers was not ideal and that a change in production operations had produced this deviation. Therefore, TEM allowed us to analyze the defective samples, propose a solution to our customer and study the improvement of the process.

Our Transmission Electron Microscopy (TEM) Service

In ATRIA we have a wide experience in the analysis of materials, from the point of view of improvement to the development of new products. Therefore, we internalize our customers’ inquiries and select the analytical tools. In the case of needing information as precise as that offered by transmission electron microscopy, the materials team advises our customers and accompanies them from the approach of the analysis, the treatment of the samples to the in-depth study of the results.

Advantages and limitations of transmission electron microscopy TEM

The main advantages of TEM are the following:

• Obtains high quality images.
• Provides structural information of the materials.
• Provides analytical information on the chemical composition of materials.
• High magnification capacity and high resolution.
• Multidisciplinary applications, for industrial and/or scientific purposes.

The main limitations of TEM are:

• Requires specialized personnel.
• It requires high-capacity infrastructures.
• High maintenance equipment costs.
• Preparation of complex samples.
• Samples must have a controlled size and must allow the passage of electrons.
• Obtaining black and white images.

Do you want to use TEM in any of your projects? Contact us!