Obviously, the exact depth evaluated by each characterization technique mentioned (XRD, XPS and Raman spectroscopy) depends on the specific parameters adopted for each analysis. However, in general, what would be the maximum depth possible to be assessed? Or what would be the sequence of characterization techniques, from the most shallow (focus on surface) to the most deep (including the bulk)?
XPS is a surface technique, you will analyze the topmost nanometers depending on the kinetic energy of the electrons.
XRD and Raman are bulk techniques so unless you apply special surface tricks your sample will have to grow thicknesses in the micrometer range for ideal investigations. Note that the sensitivity of both techniques depends highly on the material, generally XRD handles materials with a high electron density better, e.g. it's good for transition metal compounds while for organic compounds you need very good crystals to see anything. Raman depends on the polarisability, so for strongly polarizable materials (e.g. graphene) a single layer may be sufficient while for weakly polarizable materials (e.g. ceramics) the signal may be poor even if you go to the millimeter range.
There are exceptions and specifications to everything I just wrote but building on the general tone of your question this should be enough for the moment.
XPS is a surface technique, you will analyze the topmost nanometers depending on the kinetic energy of the electrons.
XRD and Raman are bulk techniques so unless you apply special surface tricks your sample will have to grow thicknesses in the micrometer range for ideal investigations. Note that the sensitivity of both techniques depends highly on the material, generally XRD handles materials with a high electron density better, e.g. it's good for transition metal compounds while for organic compounds you need very good crystals to see anything. Raman depends on the polarisability, so for strongly polarizable materials (e.g. graphene) a single layer may be sufficient while for weakly polarizable materials (e.g. ceramics) the signal may be poor even if you go to the millimeter range.
There are exceptions and specifications to everything I just wrote but building on the general tone of your question this should be enough for the moment.
The average thickness of the loose oxide layer was 10 μm for the tested samples XRD method. Please look at my last job: Article Effect of Mo Addition on the Chemical Corrosion Process of S...
best regards
M.S.
Thank you very much Mr. Jürgen Weippert for your detailed answer. It will help me a lot.
I would also like to thank both Mr. Mohamed A Elbagerma and Mr. Marcin Stawarz for your considerations.
Kindly refer the below article, you will get the info about that
https://doi.org/10.1007/s10967-017-5666-3
“Universal curve” is the right keyword which you want to do more researches in comparing these techniques. It correlates electron energy (ev) vs mean free path (A) and multiple possible substrates. If you are writing something like a review regarding surface spectroscopic techniques, I strongly recommend to add spectroscopic ellipsometry, Auger electron spectroscopy, and sum frequency generation spectroscopy. Raman is a bulk technique, but you can combine Raman with total internal reflection (TIR) configuration to make it surface sensitive method with the penetration depth ~100 nm.
Dear Mr. Thong Ly
Thanks for the additional information. Actually, I am not writing a review paper. I performed the 3 aforementioned characterization techniques in my research and found some different results between them. That's why I am asking about the average depth of each technique. I believe that this difference in results is associated with the depth evaluated in each analysis.
If you start going into universal curves, be careful: there is a "universal curve" that can be found in many textbooks that at least I couldn't trace back to any sensible origin. I recommend this work here that is also recommended by the CasaXPS suite:
Article Quantitative Electron Spectroscopy of Surfaces: A Standard D...
Andrey Mello dos Santos A nice question from you, and a professional answer from Jürgen Weippert. It deserves to follow. From my research below I performed XRD as it is a very useful technique for crystalline materials (e.g. Fe3O4 NPs), while rarely used for amorphous ones (e.g. silica nanoparticles).
Article Construction of Polymer Coated Core-Shell Magnetic Mesoporou...
Article A facile design of smart silica nanocarriers via surface-ini...
Regarding Surface Chemistry, both Zeta Potential Measurements & XPS Analysis are usually used for the extraction of chemical surface information before and after modifications. Look here for more details:
Article Improving the mechanical properties, UV and hydrothermal agi...
Article Gold Modified Polydopamine Coated Mesoporous Silica Nano-Str...
Article Synthesis and Evaluation of Water Soluble pH Sensitive Poly ...
Article Synthesis and Evaluation of Titanium Oxide Modified Mussel I...
Dear Mr. Mohammad Hegazy,
Thank you for the great addendum in this discussion.
XRD and Raman are the bulk techniques.
XRD is used to calculate the crystalline grain size, crystal structure, and lattice parameter whereas Raman spectroscopy is used to detect the rotational, and vibrational state in a molecular system.
XPS is the surface chemical technique useful for the calculation of chemical composition, electronic structure and oxidation state of the elements present in the sample.
You please see the follow link:
https://pubs.rsc.org/en/content/articlehtml/2018/nr/c8nr02278j
I hope it will work .
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction