Lead-silicate glass surface sputtered by an argon cluster ion beam investigated by XPS

The conventional ion beam sputter-cleaning technique is frequently used for removing surface adsorbates and carbon contamination from air-exposed glass surfaces. Due to the ion-surface interaction, however, an altered near-surface layer is formed with a modified composition and modified bonding. In the present work, we first examine changes in surface composition and bonding due to X-ray and electron irradiation for both air-exposed and sputter-cleaned surfaces. Then we apply argon cluster ion beam sputtering, known as a very gentle technique with respect to the changes in surface chemistry, to air-exposed lead-silicate glass surfaces analyzed by high-energy resolved core-level photoelectron spectroscopy. It was found that (i) the surface contamination present on air-exposed lead-silicate glass surfaces has a qualitative influence on the results of an XPS analysis, and (ii) Ar cluster ion beam sputter-cleaning with mean energy per Ar atom in clusters of a few eV was successfully used to remove surface contamination from air-exposed lead-silicate glass with no substantial violation of the glass surface structure. This made it easier to reveal their intrinsic surface properties.