Dear Xuguang Deng ,

when dealing with thin samples, one might have in many cases XRD information (peaks) from your sample support; in your case the substrate of the thin film. You may assign these (red marked) peak positions to the substrate material.

Which substrate do you use?

What is the estimated thickness of your film?

And what is about an oxide layer on top of your film?

You should go for the grazing incidence (GI) GIXRD mode, if possible.

Of the same importance is the X-ray optics you use. I suspect that 34.85 is a cutoff due to a filter.... Subpeaks for CuKbeta or WLalpha is also something to be looked for if you have very strong regular peaks.

Dear Xuguang Deng ,

in addition to the above comments, there is no mention on the differences in the plotted color curves in your figure. Consider the presence of another phase due to the deposition conditions changes, such as increased time, temperature, pressure, and so on.

The black and red experimental lines, whatever the deposition conditions are, have no presence of those peaks. Even a change in the substrate deposition temperature may explain new phases, due to stoichiometry break, for instance.

As the differences were not evidenced, consider all scenarios.

Best regards

WNM

It seems 34.850 degree peak is due to instrumental effect as suggested by Prof Andreas Leineweber and this link may be useful:

https://www.researchgate.net/post/The-shoulder-on-the-XRD-peak-What-could-it-be

Other two needs to be identified.

The 'shoulder' at 34,85° has an energy equivalence of about 8,3 keV. That is the Ni K-edge energy. So Ni filteration might be used to suppress ( better reduce) Cu K-beta from the primary spectrum, as it has been supposed by Andreas Leineweber .

We all should notice that a log scale is used.

The 32,453° peak's energy equivalent (on the basis of the 36° (002) peak's interplanar distance) is about 8,9keV. That is Cu K-beta. Eventhough a Ni filter is used, there is a remaining tiny Cu-K-beta line in the primary spectrum giving rise to the 32,4° peak ( log scale!).

The eqivalent energy of the 39,43° peak is about 7,38keV. That is W Ll (LIII MI transition). May arise from W contamination of the Cu target via the filament of the (perhaps old) tube. But I am not sure on its real strength. Thus a strong question mark here.

As mentioned before, the Peak at 32.45 looks like the K-Beta peak of the 002 reflection (see attached graphics with spectral lines), the next marked peak feature looks like an absorption edge and the last one could again be another K-Beta Peak from another sample reflection.