Photoemission study of adsorbed Xe on GaAs(110), HgTe(110), and Hg1-xCdxTe(110) surfaces

Synchrotron-radiation photoemission studies of Xe-atom physisorption at 35 K on cleaved GaAs(110) surfaces reveal the presence of a single first-layer adsorption site, followed at increasing coverage by the formation of a close-packed Xe second layer incommensurate with the substrate. Sizable binding-energy shifts of the Xe 4d and 5p levels from first to second adsorbed layer suggest non-negligible final-state screening of the photoemission-induced core hole by the GaAs substrate. Results for Xe atoms adsorbed on HgTe(110) and Hg1-xCdxTe(110) cleaved semiconductor surfaces show a similar initial adsorption site on all such surfaces, corresponding to an identical Xe 4d ionization energy of 66.3±0.1 eV. We associate this common behavior to initial Xe adsorption at the high-coordination, fourfold-hollow site formed by anions on the (110) cleavage plane.