Investigation of Binding Energy Scale Calibration Using Deep Core Level of Hard X-ray Photoelectron Spectroscopy with 30 keV X-ray

Abstract In hard X-ray photoelectron spectroscopy (HAXPES), which is a technique for evaluating chemical bonding states and band bending through changes in electronic potential, a precise understanding of the acquired photoelectron spectra necessitates highly accurate energy calibration of the binding energy ( E BE ). However, utilizing the Au Fermi edge or other energy calibration standards in conventional HAXPES poses challenges for the high-energy HAXPES (HE-HAXPES) under development because it excites deeper core levels than the conventional HAXPES. We searched for an alternative energy reference for the Au Fermi edge in HE-HAXPES. Since there are no Au core levels above a E BE of 20 keV, we focused on utilizing the Ag 1s core level as an energy reference. Furthermore, the E BE of the In 1s was successfully determined with reference to the Ag 1s core level. The E BE of the Au 2p 3/2 core level was also calculated, which can be referenced in the 10-20 keV E BE region. These results contribute to the establishment of energy calibration standards and the advancement of HE-HAXPES.