Photoelectron spectroscopy studies of growth, alloying, and segregation for transition-metal films on tungsten (211)
- The Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States)
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695 (United States)
High resolution soft x-ray photoelectron spectroscopy using synchrotron radiation and Auger-electron spectroscopy are used to study late-transition-metal films (Pt, Pd, Ir, Rh, Au,) on W(211). It is found that the films grow in a layer mode at 300 K. As a function of the film thickness, different 4f{sub 7/2} photoemission peaks are observed, corresponding to a single monolayer, to an interface layer, to bulk atoms and to surface atoms. Single physical monolayers of these late-transition metals on tungsten are stable against thermal rearrangement. In contrast, when multilayer films of Pd, Pt, Ir, Rh are annealed above 700-1000 K, tungsten atoms diffuse into the overlayer to form an alloy film. Gold constitutes a different case; upon annealing it does not alloy with tungsten but the metal in excess of one monolayer forms clusters. The evolution of the bimetallic systems as a function of coverage and annealing temperature is interpreted by analysis of intensities and shapes of the 4f{sub 7/2} features. Born-Haber cycles and the equivalent core approximation are used to extract thermochemical data concerning energetics of adhesion, segregation, and alloying in these early-late transition-metal systems. (c) 2000 The American Physical Society.
- OSTI ID:
- 20217467
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 62, Issue 8; Other Information: PBD: 15 Aug 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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