Advanced Analysis of Copper X-ray Photoelectron Spectra

This recent paper [1] builds upon and extends previously published X-ray photoelectron spectroscopy (XPS) curve-fitting and data analysis procedures [2,3] for a wide range of copper containing species. Steps undertaken include: 1) an examination of existing Cu 2p3/2 main peak and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter literature data, 2) analysis of a series of quality standard samples, 3) curve-fitting procedures for both the Cu 2p3/2 and the Cu L3M4,5M4,5 spectra (as well as associated anions), 4) calculations that determine the amount of Cu(II) species in a mixed oxidation state system, 5) calculations and necessary data for thin film mixed oxide/hydroxide thickness measurements and 6) a presentation of literature and standard sample values in a Wagner (chemical state) plot.

Some examples of the extensive datasets and spectra available in this paper are presented below.
Cu 2p3/2 spectra of various Cu(II) species.

Cu L3M4,5M4,5 spectra for (left) Cu(0), Cu(I) species, mineral samples, and (right) Cu(II) species.

Curve-fitted Cu L3M4,5M4,5 spectrum of wrought copper sample submerged in an Ar aerated 3M NaCl solution for 30 days.  Curve-fitting results suggest 22 % Cu(0), 65 % Cu2O and 13% Cu2S.

Cu 2p3/2 - Cu L3M4,5M4,5 Wagner (chemical state) plot with literature and standard sample data.
Cu 2p3/2 and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter literature values from Cu species


Cu 2p3/2 (main peak only) and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter values from standard samples (20 eV pass energy). b) Note that this value is specified for the Kratos instruments used in this work. Other instruments may not have this accuracy. This will also not apply for Cu(0) in a non-conductive environment where calibration to other peaks are needed (e.g. adventitious carbon C 1s which has an error of 0.1 to 0.2 eV associated with it).
Reference:
[1] M.C. Biesinger, Advanced Analysis of Copper X-ray Photoelectron (XPS) Spectra, Surface and Interface Analysis, 49 (2017) 1325-1334.
[2] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887-898.
[3] M.C. Biesinger, B.R. Hart, R. Polack, B.A. Kobe, R.St.C. Smart, Miner. Eng. 20 (2007) 152.