Electronic properties of adsorbed layers of nitrogen, oxygen, and sulfur on copper (100)

Abstract

Adsorbed layers of nitrogen and oxygen in the c(2 X 2) structure and sulfur in the (2 X 2) structure on copper (100) have been studied. Ultraviolet photoemission spectroscopy (UPS) shows that each of these layers induces a resonance above the "d band" of copper at about 1.3-eV binding energy with respect to the Fermi level and below the "1 band" at about 6-eV binding energy. X-ray photoemission spectroscopy has been used to determine that the 1s electronic binding energies of adsorbed atoms of c(2 X 2) nitrogen and oxygen are 396.3 and 529.8 eV, respectively, and that the 2p electronic binding energy of adsorbed 2 X 2 sulfur is 161. 2 eV. The highest-energy Auger peaks excited by each of these core holes may be interpreted as arising from Auger transitions involving the surface electronic states measured in these UPS experiments. Good agreement with most features of the experimental Auger spectra has been obtained using measured and calculated data for the surface electronic binding energies under the assumption that Auger final-state effects are small. Therefore the evidence points to the formation of a copper-adsorbate surface complex in which these UPS-observed resonances have a high local density of states at the adsorbate atom cores and in which the final-state hole momenta are only loosely coupled.

SHEAR STRENGTH OF METAL - SiO2 CONTACTS

“…yields the N Auger peak indicated. Analysis of the fine structure of the adsorbate peaks showed good agreement with those obtained by Tibbetts et al (5). Assuming the peak-peak heights are proportional to elemental concentration, taking into account the linear energy dependence of the sensitivity of the CMA and the Auger yields of the elements (8), it is found that the elemental concentrations for 0, N and S are in the ratio 1:.73:.77.…”

Stable and metastable structures of Co on Cu(001): Anab initiostudy

“…The surface energies, work functions and interlayer relaxations for slabs of 3, 5, 7, and 9 layers of copper are compared in Table II 27 . A further requirement of the thickness of the slab is that the interaction of the Co layers on both sides of the slab trough the substrate is negligible for the questions of concern.…”

Low-temperature adsorption of H2S on Ag(111)

“…Concerning the specific interaction of H 2 S with Ag͑111͒, almost all previous studies have focused on using H 2 S as a source of adsorbed S. In those studies, dissociative adsorption was achieved using high pressure and/or elevated surface temperature when H 2 S was in the gas phase, [1][2][3][4][5][6][7] or using electrochemical methods when H 2 S was in liquid solution. 7,8 In contrast, the present paper deals with the state of the molecule that is obtained by adsorption at low pressure and at temperatures ͑T͒ of 5-30 K.…”