I had some trouble fitting, using GenX, XRR data. The measurement was taken together with the XRD hence the data has an increase in intensity where a peak would be amplifying the kiessig fringes.
The lower angle data is fitted, but higher angle is not.
Can anyone help?
Edit:
Apologies for not being clear.
My sample is Bi2Se3 with an unkown oxide. It is grown in an MBE on a sapphire substrate. Attached is a GenX fit picture and file . and linked here is another paper on the same material pg 45-46 which has fitted correctly the XRD peaks of a lower thickness overall.
https://researchrepository.wvu.edu/cgi/viewcontent.cgi?article=6177&context=etd
(pg45-46)
Dear Muneeb Ahme , for providing meaningful answers, some more information about your samples is necessary. Furthermore, it would be good to show the data of the experiment… best regards, Dirk
Dear Muneeb Ahme ,
the Kiessig fringes show up above the critical angle of total reflection, which is mainly dependend on the wavelength/photon energy and the density of the material.
The highest density available is about 20g/cm³ (e.g. Pt).
For Pt the critical angle is about 10mrad.
When applying the Bragg law (theta ~10mrad) and 8keV for Cu K-alpha one will get a lattice spacing of about a bit lower than 400 A. So for an XRD peak in that angular range one has to have some kind of 'super lattice' with lattice constants of a few 100A; e.g. a multi-layer system.
Thus, I think, you should share some details about your sample as well as showing your reflection pattern, as Dirk Luetzenkirchen-Hecht already suggested.
Thanks in advance and best regards
G.M.
Hello Gerhard Martens and Dirk Luetzenkirchen-Hecht , thank you for the reply and I have now edited in my original post the information.
Kind Regards.
To it looks as if your model does not calculate a multilayered BiSe (so seperated Bi and Se layers) but only a mixed layer. At least this is what the density profile you shared tells me. And if so, there will never be a Bragg peak in your calculation. So You should carefully check your model and use a Bi Se multilayer instead of a mixture.
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