Suppression of Charging Effect of Insulating Materials in Hard X-ray Photoelectron Spectroscopy

The suppression of the charging effect for powder and plate -shape insulating materials in hard X-ray photoelectron spectros-copy (HAXPES) was investigated. For Cr2O3 powder materials, a method of mixed conductive powder materials such as mul-ti-walled carbon nanotube or colloidal graphite resulted in an improvement of the shifts of the photoelectron spectra to more proper positions and the lower peak widths compared with the untreated Cr2O3 powder. For a method of a conductive thin film coated on a MgO substrate, we found that a 2-nm thick Os film worked effectively to suppress the charging effect. We concluded that these methods provide a practical control for the charging effect in HAXPES measurements.