What is the best way to distinguish between silver (metallic) and silver (oxide) spectra ? I am getting Ag3d5/2 peak position as 367.32-367.86 eV of my samples after fitting. Does it suggest it is silver oxide ? Do I need to look into peak FWHM, peak asymmetry, Spin orbit splitting (interval between Ag3d3/2 and Ag3d5/2) etc. to decide if my samples are silver (metallic) and silver (oxide) ? Please see the attached spectra that I have fitted in XPS peak software. It would be nice if response is provided citing the reference.
To differentiate between metal and oxide, in principle all you need is the peak binding energy.
Alas, the NIST database (https://srdata.nist.gov/xps/EngElmSrchQuery.aspx?EType=PE&CSOpt=Retri_ex_dat&Elm=Ag) for Ag doesn't look that great since the binding energies reported there for metal and oxide are strongly overlapping. I would suggest you take a clean, at best cleansputtered silver foil as a reference. If it has the same binding energy as your sample here, your sample is metallic, if the peaks of your sample are higher than those of the reference foil or you have at least a broadening towards higher binding energies, you have oxidized silver species.
Dear Dr. S. Maidul Haque,
regarding the interpretation of Ag XPS spectra:
Ag3d region has well separated spin-orbit components (Δmetal=6.0eV).
-Peaks have asymmetric peak shape for metal.
-Loss features are observed to higher binding energy side of each spin-orbit component for Ag metal.
Small binding energy shifts for compounds, such as oxides.
-Ag3d peaks broaden with respect to metal peaks.
For more details, please see the source: https://xpssimplified.com/elements/silver.php
Best regards, Pierluigi Traverso
All possibilities listed by Pierluigi Traverso are correct; however, do I assume you have a sample in which metallic silver may have been oxidized to some extent?
In that case you could combine our two suggestions: investigate a clean metallic silver foil as I said and check the asymmetry as Pierluigi Traverso suggested. With this, you know how the characteristic shape plays out in your setup. Then turn back to your spectrum and see how the shape differs. Then, as I said, the oxide should constitute some sort of shoulder or broadening towards higher binding energies in the spectrum.