Barium

Ba 3d5/2 Values:
Barium Metal 780.1 +/- 0.7 eV, 4 citations
BaO 779.6 +/-0.3 eV, 5 citations
BaSO4 780.5 +/ 0.4, 4 citations
BaS 779.8 eV, 1 citation

From work in this laboratory:
BaTiO3 780.4 eV
BaSO4 (vacuum fractured) 780.5 +/-0.1 eV, 4 analyses

Ba 3d5/2 - 3d3/2 splitting: 15.33 eV
Ba 3p3/2: 1064 eV
Ba 3p1/2: 1138 eV
Ba 3s: 1292 eV
Ba 5p: 15 eV
Ba 5s: 31 eV
Ba 4d5/2: 90 eV
Ba 4d3/2: 93 eV
Ba 4p3/2: 179 eV
Ba 4p1/2: 193 eV
Ba 4s: 254 eV

Ba 3d XPS spectrum of vacuum fractured BaSO4.

Platinum

Table 1. Platinum 4f7/2 values.

Note the Pt metal peaks need to be fit with an asymmetric peak-shape (in CasaXPS we use LA(1.2,85,70)).  A CasaXPS ready file of sputter cleaned Pt metal can be downloaded here. This file also contains the valence band spectrum for Pt metal.  Pt 4f7/2 - 4f5/2 splitting is 3.33 eV.

Pt 4f for sputter cleaned platinum metal.

Silicon

Table 1. Common Si 2p binding energy values [1]. For Si 2p3/2 values, use the converter.

Notes:
Si 2p3/2 - 1/2 splitting is 0.6 eV (0.605 +/-0.007 eV, 114 references)

C 1s for SiC (silicon carbide) is at 283.0 eV +/- 0.8 eV.  

For Talc, Mg3Si4O10(OH)2
Si2p3/2 = 103.13 eV, Si 2p = 103.3 eV [2]
Si2p3/2 = 103.5 eV, Si 2p = 103.7 eV [3]

In Beamson and Briggs [4] Si 2p3/2 for PDMS (silicone) is at 101.79 eV (Si 2p = 102.0 eV) with the C 1s at 284.38 eV and O 1s at 532.00 eV. If we shift the C 1s to 285.0 eV then Si 2p3/2 is at 102.41 eV (Si 2p = 102.6 eV) and O 1s is at 532.62 eV.

XPS spectrum of the Si 2p and Si 2s peaks and associated plamson loss structure for a HF cleaned Si wafer. 

References:
[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.

[2] Wagner C.D., Passoja D.E., Hillery H.F., Kinisky T.G., Six H.A., Jansen W.T., Taylor J.A. J. Vac. Sci. Technol. 21, 933 (1982).
[3] Gonzalez-Elipe A.R., Espinos J.P., Munuera G., Sanz J., Serratosa J.M. J. Phys. Chem. 92, 3471 (1988).
[4] G. Beamson, D. Briggs, High Resolution XPS of Organic Polymers - The Scienta ESCA300 Database Wiley Interscience (1992) 268-269.

Common O 1s Values

Table 1. A series of common O 1s binding energy values.

From reference [1] it is found that oxygen bound to organic components can range in binding energy from as low as 530.9 eV to as high as 533.8 eV (corrected here to C 1s (C-C, C-H) at 284.8 eV).  The more common organic oxygen species (alcohols, esters, ketones, ethers and organic acids) are found in a range from 532.0 - 533.7 eV. This post shows a very handy table of organic oxygen species.

Reference:

[1] G. Beamson, D. Briggs, High Resolution XPS of Organic Polymers - The Scienta ESCA300 Database Wiley Interscience, 1992.

Oxygen 1s for Transition Metals

The O 1s BE and FWHM values obtained for the standard Sc, Ti, V, Cu and Zn samples[1] are presented in Table 1. The O 1s BE and FWHM values obtained for the standard Cr, Mn, Fe, Co and Ni samples[2] are presented in Table 2.

For many of the pure oxide samples there is a second higher BE peak that can be ascribed to contributions from a defective oxide component inherent in these oxide surfaces. Other work has shown that this is a defective oxide peak and not hydroxide as the presence of hydroxide has been ruled out by other methods[3,4]. For all of the oxides studied here this peak has an area contribution between 20 and 40 % consistent with other powdered oxides including nickel[5] and chromium[6]. These contributions from defective sites are unlikely to compromise the assignment of chemical states. It should be noted that this second peak could result from carbonates species. Inspection of the C 1s spectrum should confirm if this is occurring.

Pure oxide samples were not heated to remove possible surface hydroxides before analysis to avoid reduction of the oxide. In one related experiment in this laboratory with MnO heated to 600°C for 12 h, there was no significant change in the higher BE component ascribed to defective oxide, indicating little or no surface hydroxides are present.

Table 1. Selected O 1s values for Sc, Ti, V, Cu and Zn compounds [1].

Table 2. Selected O 1s values for Cr, Mn, Fe, Co and Ni compounds [2].

References:

[1] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887.
[2] M.C. Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2011) 2717.

[3] H.A.E. Hagelin-Weaver, J.F. Weaver, G.B. Hoflund, G.N.Salaita, J. Electron Spec. Rel. Phenom. 134 (2004) 139.
[4] P.R. Norton, G.L. Tapping, J.W. Goodale, Surf. Sci. 65 (1977) 13.

[5] M.C. Biesinger, B.P. Payne, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Surf. Interface Anal. 41 (2009) 324.
[6] M.C. Biesinger, C. Brown, J.R. Mycroft, R.D. Davidson, N.S. McIntyre, Surf. Interface Anal. 36 (2004) 1550.

Nickel

Curve fitting techniques for nickel species use specified empirical fitting parameters that take into account the unique peak shapes of the various Ni compounds[1,2]. Spectra are fitted with the asymmetric line shape and loss/satellite peaks for Ni metal (Table 1 and Figure 1) and an empirical fit of the NiO and Ni(OH)2 line shapes from parameters derived from standard samples (Table 1 and Figure 2). The binding energy differences, FWHM and area ratios are constrained for each species. The absolute binding energy values were allowed to vary by ± 0.1 to 0.2 eV to allow for error associated with charge referencing to adventitious C 1s. Overlap of the high binding energy satellite structure from Ni(OH)2 (and to a lesser extent NiO) with the 2p1/2 metal peak, which is composed of an asymmetric main peak and contributions from plasmon loss structure, can make the definition of an appropriate spectral background using only the 2p3/2 portion of the spectrum problematic. This work[2] has shown that a Shirley background applied across the entire 2p (2p3/2 and 2p1/2) portion of the spectrum works reasonably well (even though fitting of only the 2p3/2 portion of spectrum is carried out). In many cases an offset of the higher binding energy end of the background can be used to improve the fit of the peak shapes. The appropriate background offset is determined using an iterative approach while monitoring a residual plot of the 2p3/2 area. It is necessary during spectral acquisition to use a window of sufficient width (848.0 to 890.0 eV) to accurately assess the end of the Ni 2p1/2 envelope for positioning of the background endpoint[2].

Table 1. Ni 2p3/2 spectral fitting parameters: binding energy (eV), percentage of total area, FWHM value (eV) for each pass energy, and spectral component separation (eV) [2,3].

Figure 1. Ni 2p3/2 spectrum for sputter cleaned nickel metal [1].

Figure 2. Ni 2p spectra of NiO (A and B) and Ni(OH)2 (C and D) showing three different Shirley background configurations. (B) and (D) provide detail on the backgrounds at the low intensity region between the Ni 2p3/2 and Ni 2p1/2 portions of the spectra for NiO and Ni(OH)2, respectively. The fitted peaks use the Shirley background across the 2p3/2 portion of the spectra [2].

The work from [3] extends this approach to include fitting parameters for NiCr2O4 and NiFe2O4 (Figure 3), with fitting parameters also presented in Table 1. Ni 2p spectra of these two species are provided in Figure 2.  Fitting parameters for the nickel halide (NiF2, NiCl2, NiBr2) series can be found in reference [4]. Also presented in [4] are Ni LMM Auger peak-shapes and Auger parameters for a variety of Ni species.

Figure 3. Ni 2p spectra for (bottom) NiCr2O4 and (top) NiFe2O4 [3].

Figure 4. Ni LMM Auger spectra (right) and Ni 2p spectra for NiO, Ni(OH)2 and NiOOH [4].

Figure 5. Ni LMM Auger (left) and Ni 2p (right) spectra for the various nickel halides.  Note the overlap of I 3p3/2 with the Ni 2p spectrum for NiI2 [4].

Figure 6.  Further examples of various Ni(II) species Ni 2p and Ni LMM peakshapes [5].

References:
[1] A.P. Grosvenor, M.C. Biesinger, R.St.C. Smart, N.S. McIntrye, Surf. Sci. 600 (2006) 1771.
[2] M.C. Biesinger, B.P. Payne, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Surf. Interface Anal. 41 (2009) 324.
[3] M.C Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2011) 2717.

[4] M.C Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Phys. Chem. Chem. Phys. 14 (2012) 2434.
[5] M.C. Biesinger, unpublished results (2012).

Cobalt

Co metal, CoO, Co(OH)2 and Co3O4 spectra are presented in Figure 1 with spectral fitting parameters given in Table 1 [1]. Fitting parameters for CoOOH from a fit of a digitized spectrum from the work of Yang et al.[2] are also presented. As for Fe, the binding energy overlap of the various oxide and hydroxide forms will greatly increase the absolute error in speciation quantitation. However, curve fitting procedures such as those presented here, should be useful for a more meaningful interpretation for a series of similar Co containing samples. A second concern is the overlap of the higher binding energy 2p3/2 multiplet or satellite structures of the various oxides and hydroxides with the metal 2p1/2 peak at 793.1 eV. This overlap, when the metal is present, requires the use of an offset for the higher binding energy background endpoint similar to that used for Ni as described in reference [3].

Figure 1. Co 2p spectra for (bottom to top) Co metal, CoO, Co(OH)2 and Co3O4.

Table 1. Co 2p3/2 spectral fitting parameters: binding energy (eV), percentage of total area, FWHM value (eV) for each pass energy, and spectral component separation (eV).

Obtaining a pure CoO specimen for analysis is problematic. Initial analysis of a commercial CoO sample showed the surface to be extensively oxidized to Co3O4 even though the bulk powder XRD spectrum showed only CoO. This appears to be a common problem with two published databases [4,5] showing similar Co3O4 oxidized surfaces for CoO. Note: Be forewarned that this has caused some confusion in the literature.

Fitting parameters for CoCr2O4 used in reference [6] are as follows:
Peak 1: 778.8 eV +/-0.2eV, FWHM 0.84 eV, Area = Peak 2 * 0.08369
Peak 2: Peak 1 + 1.48, FWHM 2.4 eV
Peak 3: Peak 1 + 3.38, FWHM 2.4 eV, Area = Peak 2 * 0.42275
Peak 4: Peak 1 + 7.31, FWHM 4.19 eV, Area = Peak 2 * 0.61588
Peak 5: Peak 1 + 9.56, FWHM 1.88 eV, Area = Peak 2 * 0.02361

Fitting parameters for CoP from references [7] and [8].
Peak 1: 778.1 eV, FWHM 0.85 eV, asymmetry parameter in CasaXPS A(0.4, 0.6, 30)GL(30)
Peak 2: Peak 1 + 2.27 eV, FWHM 2.43 eV, Area = Peak 1 * 0.0839, GL(30)
Peak 3: Peak 1 + 4.60 eV, FWHM 2.81 eV, Area = Peak 1 * 0.102133 , GL(30)
or:
Peak 1: 778.1 eV, FWHM 0.93 eV, asymmetry parameter in CasaXPS LA(1.2,2,20)
Peak 2: Peak 1 + 2.03 eV, FWHM 2.10 eV, Area = Peak 1 * 0.085537, GL(30)
Peak 3: Peak 1 + 4.27 eV, FWHM 2.78 eV, Area = Peak 1 * 0.115933, GL(30)

Fitting parameters for Co3(PO4)2 (anhydrous or .8H20) taken from standards (courtesy of V. Beland).
Peak 1: 781.3 eV +/-0.2eV, FWHM 1.66 eV
Peak 2: Peak 1 + 1.32, FWHM 2.82 eV, Area = Peak 1 * 1.9386
Peak 3: Peak 1 + 4.92, FWHM 6.26 eV, Area = Peak 1 * 3.2241

References:
[1] M.C. Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2011) 2717.
[2] J. Yang, H. Liu, W.N. Martens, R.L. Frost, J. Phys. Chem C 114 (2010) 111.
[3] M.C. Biesinger, B.P. Payne, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Surf. Interface Anal. 41 (2009) 324.

[4] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp., Eden Prairie, MN, 1992.
[5] B.V. Crist “Handbook of Monochromatic XPS Spectra, Vol. 2 Commercially Pure Binary Oxides” XPS International Inc. (1999) pg 72-78.
[6] M. Behazin, M.C. Biesinger, J.J. Noël, J.C. Wren, Corrosion Science, 63 (2012) 40-50.
[7] A.P. Grosvenor, S.D. Wik, R.G. Cavell, A. Mar, Inorganic Chemistry, 44 (2005) 8988.
[8] A.P. Grosvenor, R.G. Cavell, A. Mar, J. Solid State Chem. 181 (2008) 2549.

Boron

Boron 1s binding energies collated from [1].

Notes:
The boron 1s peak has a low photoelectron cross-section and detection limits are generally 1 at. % or more. Significant peak overlaps are known for P 2s and plasmon loss structure from the Si 2s peak.

Reference:
[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.

p to p3/2 and d to d5/2 Binding Energy Converter

Sometimes you may have a 2p orbital binding energy reference but what you need is a 2p3/2 binding energy (or vice versa). Or perhaps you have a 3d orbital binding energy reference but what you need is a 3d5/2 binding energy (or vice versa).  This calculator allows you to easily switch between the two values.

(Note: you must download the file to Excel to use it - it is locked in Google Docs).

Copper

Table 1 lists Cu 2p_3/2 BE and modified Auger parameter values from a survey of literature sources compiled in the NIST Database[1]. Of note here is the statistically similar BE values for the Cu metal and Cu(I) oxide species. The use of the modified Auger parameter (2p_3/2, L₃M₄₅M₄₅) as well as an inspection of the Auger peak-shape do allow for a more accurate assignment for these species and has been used effectively. Goh et al.[2] have shown (in their Figure 8) the distinctly different peak shapes of the X-ray generated Auger LMM spectra for copper as the metal, Cu₂S and CuS. They also note the distinctive Cu L₃M_4,5M_4,5 peak at 916.5 eV for Cu₂O. Poulston et al.[3], in their study of surface oxidation and reduction of Cu₂O and CuO, have used both the Cu LMM and the Auger parameter to distinguish Cu(0), Cu(I) and Cu(II). These parameters are very useful for identification of the different states present in the surface but they are difficult to quantify as relative amounts of each species. The Cu 2p XPS spectrum is still the signal most used for this purpose.

Table 2 shows similar results to those shown in Table 1 from our work [4] for a series of standard samples. In this analysis, a statistical separation of the Cu 2p_3/2 peak position for Cu(0) and Cu₂O is achieved. This should be expected, as most spectrometer calibration procedures include referencing to the ISO standard Cu metal line at 932.63 eV with deviation of this line set at ±0.025 eV. Curve-fitting of the Cu 2p_3/2 line for both Cu metal and Cu₂O employed Gaussian (10 %) – Lorentzian (90 %) p and Gaussian (20 %) – Lorentzian (80 %) peak-shapes, respectively (defined in CasaXPS as GL(90) and GL(80)). Peak-shapes for these species are shown in Figure 1.

In practice, quantifying a mix of Cu(0), Cu(I) and Cu(II) species would require precise constraints on BE, FWHM, and peak-shape parameters. Resolution of these components will be difficult with larger amounts of Cu(II) compounds present due to the overlap of peaks for these three components. It may be possible to fit the 2p_3/2 spectrum using a set of constrained peaks that simulate the entire peak-shape (including the shake-up components) for the Cu(II) species present (Table 3) [4].

Table 1. Cu 2p_3/2 and modified Auger parameter literature values for Cu species (compiled from reference [1]).

Table 2. Cu 2p_3/2 and modified Auger parameter values for Cu species from [4]. [a) 932.63 eV for non-monochromatic Al X-ray source, 932.62 eV for monochromatic Al K(alpha) X-ray source]  

Table 3. Cu 2p_3/2 fitting parameters for Cu(II) species [4].

Figure 1. Cu 2p spectra for a sputter cleaned Cu metal surface (bottom), Cu₂O standard (2nd from bottom, a small amount of Cu(II) was found in this sample), CuO standard (3rd from bottom) and Cu(OH)₂ standard (top) [4].

An advanced analysis of copper XPS spectra is now available here and in reference [5].

References:

[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.

[2] S.W. Goh, A.N. Buckley, R.N. Lamb, R.A. Rosenberg, D. Moran, Geochim. Cosmochim. Acta 70 (2006) 2210.

[3] S. Poulston, P.M. Parlett, P. Stone, M. Bowker, Surf. Interface Anal. 24 (1996) 811.

[4] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887-898.

[5] M.C. Biesinger, Surf. Interface Anal. 49 (2017) 1325-1334.