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

Window, A.J., Hentz, A., Sheppard, D.C., Parkinson, G.S., Woodruff, D.P., Noakes, T.C.Q. and Bailey, Paul (2010) Silver sulphide growth on Ag(111): A medium energy ion scattering study. Surface Science, 604 (15-16). pp. 1254-1260. ISSN 0039-6028

Abstract

The interaction of S2 with Ag(111) under ultra-high vacuum conditions has been investigated by medium energy ion scattering (MEIS). 100 keV 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 (√7 × √7)R19° 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 keV 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.

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