Hi, people out there. Can you guide me in this,
We obtained an amorphous phase in XRD
but horizontally oriented rod-like morphology in SEM
Please pour your comments on it
The question is a bit too general. Please specify the following:
1) What kind of material are we talking about? If it's a purely organic polymer, getting a good XRD is much harder than for an inorganic material with heavy ions.
2) Is there no reflex at all in the XRD or is it a confused forest?
Issac Nelson Sample heterogeneity and non-representative samples. The first thing you should do is calculate how much (in ng or pg) was sampled by your techniques. You may be surprised. This is the next piece of information you must return with before further conversation.... Your situation has been seen many times before - often goes unreported as people may use the results that suit their purpose or application.
@jurgen It is an organic material. Lower thickness (30 nm). To be precise, it's C 60 fullerene.
@alan Sir. Thanks for the kind response. Pardon me for asking, what's ng or pg at the first place. We have addressing it with the lower thickness but the well defined morphology made the chaos. So we're looking for the van der waals interactions.
Issac Nelson Simple question: how much mass is assessed in each of your experiments?
@Alan sir. It's a thin film structure and 30 nm thickness is what we deposited on the already coated inorganic layer.
OK, for buckminsterfullerene a rod-like growth is surprising, the thermally stable structure would be a close packed structure.
30 nm is really thin for XRD, materials with higher electron densities such as the oxide films that I make in my current job can be analyzed with that, but carbon is probably hard.
Since I did quite some fullerene work myself in my previous job I really would like to see those rods, are you allowed to share unpublished images?
Dear Issac Nelson ,
with SEM you mainly see the surface while via XRD you will go deep into the material ( up to some µm). I suppose you mainly see the XRD signal of your support....
How does your support material ( i.e. the 'coated inorganic layer') look like in XRD without the C60 layer?
Jürgen is right. 30nm is quite thin for XRD and C i) very transparent for the x-rays used in XRD and ii) the elastic scatter strength of C is small (proportional to Z).
You should go to grazing incidence XRD (GIXRD).
For the 30nm film you should go close to the critical angle of total reflection for the incidence and the exit angle.
Issac Nelson 30 nm is not a mass. There is a spot size multiplied by the film thickness (or the penetration of the beam) and density that will give you a mass of sample. As Gerhard Martens indicates above, the different techniques penetrate to different thicknesses. Different elements have differing responses and those of low atomic mass cannot be 'seen' as easily as others.
Dear Issac,
Trying to help, what makes you think you have the buckminsterfullerene as rod-like?
How did you characterize the synthesis result previously?
The synthetic route is quite similar to achieve carbon nanotubes that often have rod-like structures.
Are you sure the final product is the C60?
I fully agree with Dr. Gerhard Martens and Jürgen, go to grazing incident XRD, with 30 nm, with a significantly lower angle, down to 0.05 at least.
Another point, even with GIXRD, if you have such orientation, rod-like, consider getting a transmission experiment.
I don't know how much you have of your sample; if deposited on an amorphous surface, you may get the transmission in situ.
Perhaps, at high resolutions, you have fringes that may help you quite a lot in your analysis.
Best regards,
WNM
Just an amendment:
critical angle of total reflection for C60 ( density ~1,65g/cm³) and Cu K-alpha (1,54A) as wave length is about 3,25mrad.
Getting XRD on such a thin film is not a trivial task. It is possible you really do not see anything reasonable. Maybe you should try small angle scattering. In general, XRD is usually used for powders, not textured thin films. And the fact that you see macrostructures (rod-like) on SEM has nothing to do with XRD - if only because their sizes are significantly larger than the parameters of the microstructure, deternined by XRD. Try to use electron backscatter diffraction regime.
You dig?
Thanks for the valuable suggestions. Got the clear view on it. Have to go for SAXS/GIXRD or any other sophisticated electron diffraction techniques.
https://www.sciencedirect.com/topics/materials-science/x-ray-diffraction-analysis
https://www.sciencedirect.com/topics/materials-science/x-ray-diffraction-analysis
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