your background curves need to be below the noise level of your spectra. For your data to be useful you need to integrate the total area of your peaks. I'm not sure what software you are using, but the backgrounds should be Shirley if you want to use the canonical XPS analysis approach. This pdf will be helpful:

http://www.casaxps.com/help_manual/manual_updates/peak_fitting_in_xps.pdf

your background curves need to be below the noise level of your spectra. For your data to be useful you need to integrate the total area of your peaks. I'm not sure what software you are using, but the backgrounds should be Shirley if you want to use the canonical XPS analysis approach. This pdf will be helpful:

http://www.casaxps.com/help_manual/manual_updates/peak_fitting_in_xps.pdf

Dear Sir,

the referee is absolutely right since you use a background model I´ve never seen before - namely a constant background. This may work only in case of Fig. (e). According to the suggestion by D.H.K.J. use a Shirley background or at least a LINEAR background. The latter may also work since the increase of background is not very steep within these spectral ranges.

Sincerely, FM

Dear Inderjeet, there are several points that are striking:

First of all, for the Ti 2p spectra, the level of your fitted data is substantially lower that the measured data, in particular between the Ti 2p3/2 and the 2p1/2 peaks. Thus the resulting intensity is negative in this range, which makes no physical sense. As recomment by David Jackson, I agree in using Shirley (or Tougaard) background function, but a linear background correction typically will fail.

Second, the Ti 2p 3/2 peaks are not fitting the data on the low energy side of the peak, this implies that the Gaussian/Lorentzian shape or the mixing coefficient is not properly set. From my own experience in fitting Ti-oxide species, I think that pure Gaussian peaks are not always adequate, neither pure Lorentzians ...

Third point to be mentioned: The totally different width of the two oxygen species in the O1s spectra. Why should the FWHM be so different? I guess this is a factor of about 2! So I feel that an oxygen species is missing. My peak assignment would be the Ti and /or Zr oxide at the lowest binding energy of about 529.5 eV, adsorbed water at roughly 532.5 eV, and some chemisorbed oxygen at an intermediate binding energy.

I would thus recomment to check XPS literature and reference spectra forbetter and more reliable fit results!

Good luck, Dirk

Thanks to Drik and Frank.