François, thank you for posting a summary of the suggestions you received,
and for posting your images to your web site, not to the whole list :-)
I urge people to reply to the whole group, not just privately, since such
questions are of general interest.
What you describe as different asymmetry
Thank everyone for all the answers (on and off)
If I can resumed all the ideas :
Question about the darkness of the pellets (could it be reduction
process ?) I should asked the student about the sintering. The ZnO is
doped with Ti/Al and Mg.
Question about the peak shift : it is true than
