Energy Dispersive x-ray spectroscopy (EDS)
Description
When a high energy electron beam interacts with matter x-rays are produced. An x-ray spectrometer can detect and count these providing information on the elemental content where the electron beam is focused. On the S-4300 SEM and the 2010F STEM, this beam can be computer controlled and elemental profiles and maps can be produced. Spot analyses can be performed on our S-3200 SEM and 2000FX TEM.
Specifications
- SEM resolution is about one micron to 10 nm.
- STEM resolution is about 1 nm.
- Sensitivity is about 1 percent for both SEM and STEM
Instrumentation
- S-4300 SEM: PGT micro2-CE
- S-3200 SEM: Noran system
- JEOL 2010F STEM: Oxford det. with EsVision
- JEOL 2000FX: Oxford INCA system
Advantages
- Straight forward interpretation with automated semi-quatitative analysis
Limitation
Sensitivity of approximately one percent
Semi-quantitave analysis accuracy of approximately 10 percent
For elements lighter than Na sensitivity rapidly decreases.
Mapping can take hours, especially when there are elements with a low percentage concentration
Examples
Example EDS spectrum
Example semi-quantitative EDS map of bi-metallic catalyst obtained on JEOL 2010F.
Map acquired in approx 30 minutes, 150 pixels by 100 pixels.
Optimized EDS mapping developed by Alan Dozier supported by NanoTEM Corp.
