Abnormal X-ray photoelectron spectroscopic peak shifts of AgCl introduced by the XL magnetic lens and its application in imaging X-ray photoelectron spectroscopic analysis

A flat AgCl/Ag specimen was analyzed using X-ray photoelectron spectroscopy (XPS). The Ag sheet in the specimen was electrically contacted with the stainless steel sample holder. The specimen was irradiated with unmonochromatized AlK alpha X-ray. The photoelectrons were collected using the XL magnetic lens. An abnormal peak shift up to 28.3 eV has been observed for Ag3d spectrum of insulating AgCl while no peak shift is observed for Ag3d spectrum of metallic Ag. Ibis abnormal peak shift has been attributed to the charging effect introduced by the use of the XL magnetic lens. The chemical shift of Ag3d binding energy between Ag-0 and Ag+ in AgCl is only 0.4eV, impling that AgCl can not be distinguished from metallic Ag in the Ag3d XPS image when the XL magnetic lens is not used. However, since Ag3d peak of AgCl shifts far from the Ag3d peak of metallic Ag when the XL magnetic lens is used, AgCl can be distinguished from metallic Ag in the Ag3d XPS image of AgCl/Ag specimen.