Ag nano particles are deposited by electron beam evaporation method on mechanically exfoliated MoS2. And XPS data were taken freshly after Ag deposition and after long exposure to ambient atmosphere.
Suspect that you have oxidized the surface and especially the Ag. The silver will be in the +1 oxidation state. Argon ion etch to the bulk material (probably > 10 -15 atomic layers) to remove.
Thanks for your answer Sir, I am also sure about the oxidation of Ag. But I want deeper understanding on the enhanced broadening of S2s peak after oxidation.
We have
MoS2 226.17
Ag-S-S-Ag 227,22
S4+ 232.56
Silver disulphide or Ag2S is consequently formed.
i appreciate your information Sir, but I am a novice to XPS analysis and does it mean that the peak fittings I have done in the picture attached are wrong, may I have more detail please?
According to our data, pure Mos2 has a peak S 2s of 226.17 eV. Your peak is 226.54eV. Consequently, it is shifted to the peak of the disulphide or silver sulphide 227.22 eV.
You have to compare the metal sulfide and metal disulfide bond. As you know sulfur has variable oxidation states depending upon the nature of oxidation state the pattern may change. You please refer some papers on high light sulfur on silver and gold surfaces. area of the peak splitting also give you some information.
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