Recent advances in dual mode charge compensation for XPS analysis

Abstract

Dual mode charge compensation has been used successfully for many years to enable X-ray photoelectron spectroscopy (XPS) analysis of a variety of insulating samples. This approach uses a combination of low energy electrons and argon to compensate for positive charge build-up during irradiation by X-rays. Whilst this method works with no detectable side effects in most cases, it was recently reported that the chemical bonding states of some Cr(VI) oxides may be modified by prolonged exposure to the flood source. In this work, we demonstrate successful dual mode charge compensation of CrO3 with no discernible sample modification from the flood source. Under the same flood source conditions, we extend the analysis to other systems known to undergo reduction and present charge compensated XPS data for V2O5 and a copper-based metal-organic framework (MOF) showing little or no modification from the flood source, even with prolonged exposure.