Adsorption and decomposition of ammonia on a W(110) surface: Photoemission fingerprinting and interpretation of the core level binding energies using the equivalent core approximation

The first detailed study of photoelectron spectra of Sb2Te2Se and (Bi0.7Sb0.3)2Se3 (111) clean and sputtered surfaces is presented as part of an XPS examination of the surface chemistry of these and related materials. The core level binding energies and surface chemical composition have been determined from the XPS data. On substitution of Te by Se in Sb2Te3 leading to Sb2Te2Se the core level binding energies in Sb and Te increase by 0.3 eV while in Bi2Se3 the binding energy of core electrons does not change on replacement of Bi by Sb. The measured core level shifts are caused by changes of the initial state charge distribution and result in increase of average ionicity of bonding in the Sb2Te2Se crystal. The surface composition of Sb2Te2Se sample calculated from intensities of photoelectron spectra agrees well with the bulk composition of the crystal while (Bi0.7Sb0.3)2Se3 sample shows enrichment in Bi. The effect of argon ion bombardment on surface composition for various impact conditions has been investigated. The surface enrichment in Sb and Bi for Sb2Te2Se and (Bi0.7Sb0.3)2Se3 sample due to different atomic sputtering yields is observed. It follows from the relative intensities of photoelectron spectra measured at different detection angles that the ordered arrangement of the superficial layers sampled by the XPS method is damaged by sputtering at ion energies as low as 200 eV and doses I > 2 . 1015 ion/cm2.

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Application of slater's transition state theory to the core-level binding energies of simple metals in atom in jellium model

Physics Letters A ◽

10.1016/0375-9601(84)90761-8 ◽

1984 ◽

Vol 100 (4) ◽

pp. 204-206 ◽

Cited By ~ 5

Author(s):

D.G. Kanhere ◽

G.S. Sohoni ◽

S.J. Mali

Keyword(s):

Transition State ◽

Transition State Theory ◽

State Theory ◽

Binding Energies ◽

Core Level ◽

Jellium Model ◽

The Core

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Core-Level Photoemission From Stoichiometric GaN(0001)-1×1

MRS Internet Journal of Nitride Semiconductor Research ◽

10.1557/s1092578300000521 ◽

2005 ◽

Vol 10 ◽

Cited By ~ 10

Author(s):

S.M. Widstrand ◽

K.O. Magnusson ◽

L.S.O. Johansson ◽

E. Moons ◽

M. Gurnett ◽

...

Keyword(s):

Binding Energy ◽

Photoelectron Spectroscopy ◽

Binding Energies ◽

Core Level ◽

Complex Structures ◽

Dangling Bond ◽

X Ray ◽

The Core ◽

Slight Excess ◽

Bulk Gan

We report on a high-resolution x-ray photoelectron spectroscopy (HRXPS) study using synchrotron radiation, for the identification of the core level binding energies of Ga 3d and N 1s, from a stoichiometric Ga-polar GaN(0001)-1×1 sample.Three surface shifted components were found on the stoichiometric surface for the Ga 3d feature. The first surface shifted component has a higher binding energy of 0.85 eV, and is interpreted as surface Ga with one of the N bonds replaced by an empty dangling bond. This structure is belonging to the stoichiometric clean and ordered Ga-polar GaN(0001)-1×1 surface. The second, with a binding energy relative the bulk of −0.76 eV, is interpreted as Ga with one of the bonds to a Ga atom, which indicates a slight excess of Ga on the surface. The third surface shifted component is shifted by 2.01 eV and is related to gallium oxide in different configurations.The N 1s feature is complex with five surface shifted components relative the bulk were found. Two components with binding energy shifts of −0.54 eV and 0.47 eV are interpreted as surface shifted core levels from the stoichiometric, clean Ga-polar GaN(0001)-1×1 surface.We also analysed the Ga 3d spectrum after deposition of 1.5 ML of Ga on a stoichiometric surface. The surface shift for the Ga 3d5/2 component from the Ga overlayer is −1.74 eV relative the bulk GaN.The C 1s and O 1s core levels from remaining surface contamination have also been line shaped analysed and show complex structures.

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