Silver sulphide growth on Ag(111): A medium energy ion scattering study

SURFACE SCIENCE

卷:604

Article

Window, A. J.¹  Hentz, A.¹  Sheppard, D. C.¹  Parkinson, G. S.¹  Woodruff, D. P.¹  Noakes, T. C. Q.²  Bailey, P.² 

[1] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England

[2] STFC Daresbury Lab, Warrington WA4 4AD, Cheshire, England

关键词: Medium energy ion scattering (MEIS);    Molecule-solid reactions;    Corrosion;    Compound formation;    Silver;    Sulphur;    Sulphides;   

DOI  :  10.1016/j.susc.2010.04.009

来源: Elsevier

【 摘 要 】

The interaction of S-2 with Ag(111) under ultra-high vacuum conditions has been investigated by medium energy ion scattering (MEIS). 100 key He+ MEIS measurements provide a direct confirmation of a previous report, based on thermal desorption, that the growth of multilayer films of Ag2S occurs through a continuous corrosion process. These films show a commensurate (root 7 x root 7)R19 degrees unit mesh in low energy electron diffraction, consistent with the epitaxial growth of (111) layers of the high-temperature F-cubic phase of Ag2S. The substantial range of co-existing film thicknesses found indicates that the growth must be in the form of variable-thickness islands. The use of 100 key H+ incident ions leads to a very rapid decrease in the sulphide film thickness with increasing exposure that we attribute to an unusual chemical leaching, with implanted H atoms interacting with S atoms and desorption of H2S from the surface. (C) 2010 Elsevier B.V. All rights reserved.

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