Overview

• Post By : Kumar Jeetendra


• Source:


• Date: 22 Mar,2025

Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) are powerful tools for material analysis. They both provide useful details about a material’s structure and composition.

But how do they work? Let’s discuss it stepwise.

Step 1: Scanning Electron Microscopy (SEM)

1. SEM involves scanning a focused beam of electrons over the surface of a sample. The surface of the material, together with its geometry, give rise to different signals which when detected, can be converted into an image.
2. High Energy Electron Beam Generation: The electron gun produces a beam of high energy electrons.
3. Scanning: Electromagnetic lenses focus and aim the directed electron beam on the sample.
4. Interaction: When the sample is being irradiated, secondary electrons (SE) and back scattered electrons (BSE) are released.
5. Detection: The emitted electrons are collected by the detectors to give high graphics resolution images.

Scanning Electron Microscopy view details of a sample surface and its shape with nanometer level of precision and resolution.

Step 2: Analyze Elemental Composition Using Energy EDS X-ray Spectroscopy (EDS)

1. Together with scanning a sample’s surface with SEM, EDS is meant to determine the sample’s elemental composition. This method is predicated upon X-rays being emitted from a sample interacting with an electron beam.
2. Excitation of Electrons: The electron beam knocks out from the sample the electrons that are in the inner shell.
3. “X-ray Emission”: These X-rays are emitted when outer electrons fill the gaps with X-ray emissions characteristic to their energy.
4. “Detection and Analysis”: These X-rays with their specific energy are captured and identified by the EDS detector and elements are recognized accordingly.

Also read:

SEM vs. EDS: What Are the Main Differences?

The EDS automatically detects both qualitatively and quantitatively the elemental content of the sample.

How SEM and EDS Work Together

The integration of SEM and EDS enables the researcher to capture the surface image of the sample and at the same time analyze its elemental composition. This capability is vital in material characterization, failure analysis or even in contamination detection.

For example:

1. SEM captures the high magnification images of a fractured metal sample.
2. EDS detects the contaminants or inclusions which are suspected to have caused the failure.

Advantages of SEM/EDS Analysis

1. High-Resolution Imaging: The details of the surface from SEM are not matched by any other technique.
2. Elemental Identification: EDS delivers the exact identification of the elements.
3. Non-Destructive Testing: Both methods are low impact, simple to carry out methods.
4. Versatile Applications: Effective in fields from material science to pharmaceutical.

Conclusion

Grasping the synergy of SEM and EDS enables researchers and engineers to make better choices on the material properties and failure mechanisms. This pair of techniques gives materials both visual data and composition data providing a fully comprehensive answer.