Towards Absolute Energy Referencing in XPS

ABSTRACT An inherent difficulty in X‐ray photoelectron spectroscopy (XPS) regards the frequent emergence of spectral shifts due to probe‐induced surface charging. Various energy‐scale correction methods were already proposed, yet it is generally agreed that no fundamental answer to this problem has been demonstrated so far. Here, a method is proposed that can, in principle, address this issue and lead to a transformative improvement in XPS analyses. The method is based on extrapolation to the “zero exposure state” of the sample, based on a reference measurable at nearly zero charging conditions. Temporal changes in the surface potential can thus be monitored at high accuracy and subsequently be implemented to get the desired energy‐scale calibration. This methodology demonstrates remarkable improvements in reliability and applicability of both the chemical and electrical XPS‐based analyses.