Characterization of ultrathin platinum overlayers deposited on A W(110) surface
1988; Elsevier BV; Volume: 163; Linguagem: Inglês
10.1016/0040-6090(88)90454-3
ISSN1879-2731
AutoresS. M. Shivaprasad, R. A. Demmin, Theodore E. Madey,
Tópico(s)Molecular Junctions and Nanostructures
ResumoThe growth of platinum overlayers (sub-monolayer to multiple layer coverages) on a clean W(110) surface is studied by Auger electron spectroscopy (AES) and temperature programmed desorption (TPD). Based on Auger peak amplitudes, thermally evaporated platinum appears to grow in the Frank-van der Merve mode on W(110), at least for the first few layers. Annealing of platinum deposited at 90 K shows distinct changes in Auger ratios and adsorption states of molecular CO, providing evidence for changes in the electronic and structural properties of the overlayers. TPD of CO, combined with AES measurement, suggests that ennealing induces either agglomeration of the platinum atoms into large islands with a small cluster density, or the formation of a surface PtW alloy. Annealing above 1500 K produces a stable monolayer of platinum on the tungsten surface for all initial platinum coverages greater than one monolayer. Preliminary low energy electron diffraction (LEED) studies are consistent with the observed trends in the structure of the platinum overlayers on W(110).
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