Experimental calibration curve for quantitative XPS analysis constructed from in situ fractured polycrystalline manganese silicide surfaces

In the present study, we prepared clean surfaces of polycrystalline Mn ₃Si, MnSi, and Mn ₁₁Si ₁₉ by fracturing them in a spectrometer under an ultrahigh vacuum, and then attempted to construct a calibration curve for a quantitative XPS analysis by measuring these clean surfaces. We ensured that there were no C 1s and O 1s peaks in the survey XPS spectra for the fractured surfaces. In the case of Mn ₁₁Si ₁₉, a positive chemical shift in the binding energy of the Mn 2p level was observed, whereas a slight negative shift in the binding energy of the Si 2p level was observed in the cases of MnSi and Mn ₃Si. The spectral intensity ratios of Mn 3p to Si 2p and Mn 3s to Si 2p were proportional to the atomic ratio of Mn to Si, indicating that these relationships could be used as the calibration curve. On the other hand, no linear relationship was observed for the ratio of Mn 2p to Si 2p.