Erratum: “Practical guides for x-ray photoelectron spectroscopy: First steps in planning, conducting, and reporting XPS measurements” [J. Vac. Sci. Technol. A 37, 031401 (2019)]

In Ref. 1, the labels identifying features A and C in Fig. 1(a) were reversed in the second sentence of the second paragraph of Sec. 1 of the Appendix, and the description of feature B was incomplete. We now provide a corrected and slightly expanded version of this complete paragraph:

Figure 1(a) shows two clearly identifiable features, a sharp peak from Ni 2p_3/2 (feature C) and a broad region at higher binding energy. The intensity of feature B in the latter region is partly due to inelastic scattering of electrons from the Ni 2p_3/2 peak and partly due to intrinsic excitations associated with photoionization from the Ni 2p_3/2 shell.² Feature B has often been identified as a “6 eV satellite” (i.e., an intrinsic excitation) in the XPS literature. Feature A is due to Ni 2p_1/2 photoelectrons excited by Mg Kα₃ and Kα₄ X-ray satellite radiation) arising from the use of unmonochromatized X-rays. The relative intensities and the energy positions of the Mg satellite peaks are known,^2,3 and their contributions can be included in the peak fit shown in Fig. 1(a). We note that the Shirley background shown in Fig. 1(a) empirically accounts for most of the electrons that were inelastically scattered from the Ni 2p_3/2 peak or for some intrinsic excitations, although it was necessary for the fit to include an extra peak for feature B. This fit to the 40 eV range fitted both the Ni 2p_1/2 and Ni 2p_3/2 regions using a Voigt function (a convolution of Gaussian and Lorentzian curve shapes)⁴ with the parameters listed in Table III. The main Ni 2p_1/2 signal from the Mg Kα_1,2 X-radiation is not shown in Fig. 1(a).

The last sentence of the first paragraph of Sec. 2 of the Appendix is now revised for clarity and consistency with Appendix Sec. 1 to read: Feature B in Fig. 1(a) has often been interpreted as a “6 eV satellite” (i.e., an intrinsic excitation occurring with photoexcitation of the Ni 2p_3/2 core level).There is also considerable intensity from Ni 2p_1/2 electrons excited by Mg Kα₃ and K α₄ X-rays (these satellite peaks are labeled A). The main Ni 2p_1/2 peak is not shown.