I think the short answer is "no". As mentioned above, EDX has a large interaction volume, on the order of µm in SEM and 100s of nm in TEM.
The ideal tool for analysing surface composition is X-ray photoelectron spectroscopy (XPS). It is only sensitive to the top 5-10nm. The only catch with this technique is it is VERY sensitive to surface contamination.
EDS gives you elemental composition of your sample, but no topography/morphology. However, it's usually done attached to an SEM or TEM, which could give you that kind of information.
Hi Yousif,
I am also interested in looking at the answers for this question.
To my knowledge, it depends on how thick is your sample. If we are looking to collect EDS from a point, it would collect all the X-rays within a sphere of diameter ≈ 1.5 - 2 μm, with our point being on the surface of the sphere. So, I would say it can be surface technique based on the thickness (probably > 100 μm) of the sample.
As I said, I look forward for different answers.
"energy dispersive" means that the x-ray fluorescence is resolved in photon energy. That allows you to identify the contributing elements through their characteristic radiation.
Whether you consider it a surface analysis tool depends on what you wish to achieve (i.e. what length scale you are interested in both, laterally and depth- wise, repectively). In principle, as was said before, in conjunction with a TEM or SEM, you can obtain spatial resolution, because the primary electron beam is narrowly focussed (well below 1 nm is possible). However, the excitation volume from which X-rays shall be emitted is much larger than this.
Please consult appropriate introductory literature on SEM. Someone might suggest good literature for that purpose. I have none at hand right now.
I think the short answer is "no". As mentioned above, EDX has a large interaction volume, on the order of µm in SEM and 100s of nm in TEM.
The ideal tool for analysing surface composition is X-ray photoelectron spectroscopy (XPS). It is only sensitive to the top 5-10nm. The only catch with this technique is it is VERY sensitive to surface contamination.
As Manuel said, XPS is definitely much more surface-limited. Depending on your definition of surface, though, one could consider EDS a surface technique. Say, for instance, that you are looking at a coarse-grained steel alloy where the grain size is hundreds of microns. Then an interaction volume of a micron might still fall within what industry might consider the "surface."
For nanoscale materials XPS is the way to go. However, because of contamination issues it is common to fracture materials in situ or use other methods to achieve a clean surface.
Thanks to all for the contribution, I would like to add one of my result that I have by AFM which showing smooth layer on the top of a thin film, this layer was confirmed by SEM and NanoSAM as well, but I tried to see it with EDS and I could not see it although I sow it by BES in the same experiment.
Hm, I see grains, some appear to be in a "second layer". Then I see parts of the images as "cloudy", rather diffuse. Is the latter what you name smooth layer?
What have you seen in BES and what kind of result would you have expected which would have qualified as "I have seen the smooth layer"?
No, I did not do quantities analysis but the other result you can see it in one of my paper (Improved luminescence properties of pulsed laser deposited Y3(Al,Ga)5O12:Tb thin films by post deposition annealing), is confirm to be kind of Ga oxide, the BES show it as dark area.
Not really it gives you primarily bulk information with spatial resolution of the electron beam which penetrates quite deep. The resulting fluorescence from the core electron ionization by the high energy electron beam has this depth information because the photons have moderate energy and are not so readily absorbed by the intervening sample on the way out. The other part of the core relaxation involves the emission of an Auger electron which undergoes many more collision processes and consequently only escapes from the surface. So a Scanning Auger microscope has this chemical resolution (There is a relatively new text on this from M. Prutton and M. El Gomati Scanning Auger Electron Microscopy, Martin Prutton (Editor), Mohamed M. El Gomati (Editor) ISBN: 978-0-470-86677-1). p.s. both techniques quantify fairly well.
Sorry when I searched the answers I did Auger and not SAM. In all of the the methods that you employed above its only the EDS which uses photons. The rest are electrons and all of them employ apart from BES employ relatively low energy electrons: So I would expect perhaps the BES (back scattered electron scattering? to show more similarity with the EDS) but electrons nonethe less are you looking at reflected electrons with the primary energy.
As Kai says what are the clouds
if you have EDS by electrons then the deep skin of the electron is less than 1 micrometer, depending that you consider surface you will have the answer, remember, the surface concept is not simple.
I agree with Sebastian, an analysis 10nm beneath the surface is still considered as a surface analysis. In electron spectroscopies such as XPS and AES the detected electrons can travel only few nanometers without losing energy while they travel towards the surface to get out and reach the detector. In EDS the detected signal are x-ray photons that depending on how deep is the the excited region could come from few microns below the surface. EDS from SEM experiment is that case.
In general I agree with all of the answers given so far. However, EDS can be made surface sensitive at least to some extent. Think about tilting a flat sample with respect to the electron beam. Then the interaction volume of the (primary) electrons with the sample become smaller and smaller. Using an appropriate energy of the incident electrons, the interaction volume can be quite small - you may estimate this volume by the use of free software such as casino (http://www.gel.usherbrooke.ca/casino/ - don't use the 3D-versions 3.x, the 2D-version is easier to handle and gives good results). Then you will see that you are able to measure thin films of say 10 nm thickness properly. I know experiments of this type, that have studied the annealing and intermixing of metal multilayers at elevated temperatures, with convincing results (check: Mikrochimica Acta Supplement 15 (1998) 171).
Unless, yes, XPS may do it better, but there are laboratories that do not have access to XPS but a SEM with EDS running ... Best regards, Dirk
Energy Dispersive X-ray Spectroscopy (EDS) is an analytical capability that can be coupled with several applications including Scanning Electron Microscopy (SEM),Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM).
EDS, when combined with these imaging tools, can provide elemental analysis on areas as small as nanometers in diameter. The impact of the electron beam on the sample produces x-rays that are characteristic of the elements present on the sample. EDS Analysis can be used to determine the elemental composition of individual points or to map out the lateral distribution of elements from the imaged area.
Elemental Mapping - Characteristic x-ray intensity is measured relative to lateral position on the sample. Variations in x-ray intensity at any characteristic energy value indicate the relative concentration for the applicable element across the surface. One or more maps are recorded simultaneously using image brightness intensity as a function of the local relative concentration of the element(s) present. About 1 μm lateral resolution is possible.
Line Profile Analysis - The SEM electron beam is scanned along a preselected line across the sample while x-rays are detected for discrete positions along the line. Analysis of the x-ray energy spectrum at each position provides plots of the relative elemental concentration for each element versus position along the line.
Ok i just want to say that it is possible that EDS can give information about the surface topography
Thanks to all for the good information, now I can say EDX is not a surface science technique.
The term 'surface science technique' is too broad. You can get some information about the surface/below surface constituents but this would not qualify to a surface sensitive or surface specific nature.
No it is analytical technique used for elemental composition of material or chemical characterization of a sample.
I confirm that:
Our Energy Dispersive X-ray (EDX) or Energy Dispersive Spectroscopy (EDS) system consists of a PGT light element x-ray detector mounted on our Topcon ABT-32 SEM. The EDX uses Evex VIDX Microanalysis signal capture, data analysis, and data presentation software. Its capabilities include:
• Acquisition of up to eight signals at once during a scan. Eight characteristic x-ray emission lines may be acquired at once to map 8 elements. Alternatively, one of the channels may be dedicated to acquiring a secondary electron or a backscatter election image while 7 elements are detected.
• Spot, line, and area maps of elements can be generated. These maps may be color codedwith several elemental maps superimposed. The elemental map may be superimposed on the secondary electron or backscattered electron images.
• While the secondary electron image may have a resolution of a few nanometers, the x-ray emission spectrum has a much larger volume of material as its source. X-rays are emitted throughout the volume of material into which the electron beam is scattered and decelerated, so the resolution is commonly 1 micrometer laterally and about 1 – 2 micrometers in depth.
• Sample sizes suitable for EDX analysis are the same as those suitable for SEM analysis.
• Quantitative elemental concentrations can be determined at a spot or over an area.
• Image-Pro Plus image analysis software provides counting and sizing and measurement capabilities.
We discuss the issues of whether quantitative elemental composition analysis of a sample is best obtained using EDX or XPS or both techniques elsewhere.
I agree with Manuel Schnabel and other person . SEM- EDS has interaction volume.
I agree with Manuel Schnabel and other person. But, I have another problem. Is EDS sensitive to metal dispersion ? Would be the same amount of metal particles (supported on some carrier) somewhat differently analyzed for very small (say 1-2 nm in size) metal particles compared to more bulky material ?
Atomic Force Microscopy (AFM) is a suitable tool for analyzing surface of your samples. It will give you 3D surface profile.
Complementary information! thanks everybody for sharing scientific idea and knowledge. 🙏🙏🙏🙏🙏🙏
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