Compositional analysis of materials

Electron microscopes with detectors for energy dispersive X-ray spectroscopy (EDS) systems are used for element mapping and semiquantitative microanalyses of a wide range of samples. At ELMILAB one SEM (Supra 55) and one TEM (JEM 2100) instruments are equipped with EDS systems.

SEM-EDS analyses are frequently combined with topographic imaging to check the elemental composition of structures of interest. The best analytical quality is however obtained on flat samples and under high vacuum. In this case, EDS analyses are usually combined with backscatter electron (BSE) imaging, which visualizes compositional differences by contrast variations. For non-conducting samples, the type of coating material needs to be considered. Coating with carbon is most common as this light element interfere very little with other elements.

TEM-EDS element mapping or microanalyses are performed on very small particles or ultrathin sections at high vacuum. The 200 kV TEM at ELMILAB allows for elemental analyses at very high magnifications.