X-ray photoelectron spectroscopic chemical state quantification of mixed nickel metal, oxide and hydroxide systems

Quantitative chemical state X-ray photoelectron spectroscopic analysis of mixed nickel metal, oxide, hydroxide and oxyhydroxide systems is challenging due to the complexity of the Ni 2p peak shapes resulting from multiplet splitting, shake-up and plasmon loss structures. Quantification of mixed nickel chemical states and the qualitative determination of low concentrations of Ni(III) species are demonstrated via an approach based on standard spectra from quality reference samples (Ni, NiO, Ni(OH)(2), NiOOH), subtraction of these spectra, and data analysis that integrates information from the Ni 2p spectrum and the 0 1s spectra. Quantification of a commercial nickel powder and a thin nickel oxide film grown at 1 -Torr O-2 and 300 degrees C for 20 min is demonstrated. The effect of uncertain relative sensitivity factors (e.g. Ni 2.67 +/- 0.54) is discussed, as is the depth of measurement for thin film analysis based on calculated inelastic mean free paths. Copyright (C) 2009 John Wiley & Sons, Ltd.