EDS is an analytical technique used for the elemental analysis or chemical characterization of a sample. EDS effectively gives the "bulk" concentration of elements present in a sample, but very little information about the speciation or oxidation state of each element. On the other hand, XPS gives the near surface region chemical composition of the sample (i.e. the elements present in the top few nm (around 10 nm) of the sample). In EDS, this depth is around µm.

Therefore, XPS is used for elemental analysis due to its better accuracy. XPS is better for surface composition (few nm penetration depth), while EDS is better for composition mapping within the top few micrometers (although some XPS instruments also allow for lateral resolution).

Discard your EDS results. EDS is not good for nanosheets. Do not forget to tell EDS operator about it.

With SEM-EDS, an interaction volume is associated which includes the surface of the sample and also some volume beneath it. The depth of this interaction volume depends upon the electron beam energy of the instrument. So, there is a high probability that the total area of analysis in XPS and SEM is different which gives rise to the difference you have observed.

Also, the error associated with EDS data is around 10% and hence is not as reliable as XPS would be for quantitative analysis.

I hope this helps.

I agree with above mentioned reason - i.e. different interaction volume (or depth simply put). It is not exceptional that samples exhibit inhomogeneity (composition of thin surace layer differs from overall composition). It should also be taken into account that instrument calibration may not be performed well / perfect and sensitivity to the same elements may be different too. Therefore, different results of EDS and XPS could also be recorded on a strictly homogenous sample. I prefer not to say better is one or the other. The right choice of method for a particular sample and, last but not least, the correct interpretation of the obtained data is essential. Unfortunately, often we can see the interpretation of surface analysis as an overall composition (and then the error can be even tens of percent or even the actual composition is undetected) and this can concern not only XPS but also EDS or XRF analysis. If the sample thickness is not comparable to the interaction volume, it is better to perform cross-sectional control analyzes (if possible).

EDX measures X-rays emitted from a sample, while XPS measures photoelectrons emitted from a sample.

EDX is an analytical technique used for the elemental analysis or chemical characterization of a sample, On the other hand, XPS measures the kinetic energy and number of electrons that escape from the top 1 to 10 nm of the material being analyzed. XPS requires ultra-high vacuum (UHV) conditions.

Hello! Can someone tell me why in a EDS analysis made in section on a layer of Cu deposited on a steel support, appears also Fe on the diagram?

The thickness of the Cu layer is 22 microns, and the EDS analysis made on the sample surface indicates 100% Cu, but in section, it finds Fe from the steel support, therefore, the final composition of the layer gives it as being 22% Fe and 78%Cu. How can I fix this?

@Zarnescu - Ivan Nicoleta

This is possible because of the larger interaction volume of the electron beam beneath the sample surface from which the signal emanates for EDS analysis.

Given the thin 22micron Cu layer, it is highly probable that some region of the Steel support layer will also be included in your data.

Try taking point data scan away from the Steel support layer to minimise the interference from Fe signal.

I hope this helps.

Asif Shahzad, both techniques work on different phenomena. XPS works on the photoelectric effect and collects information using these, while SEM_EDS collects information using scattering. XPS only gives information for the topmost layer (~atleast 10 nm) while SEM-EDS collect the information using secondary and backscattered electron from deep regions that are the reason for electron microscopy always give better information atomic wt % of chemicals comparison to XPS.