AVS 66th International Symposium & Exhibition
    Surface Science Division Tuesday Sessions
       Session SS-TuP

Paper SS-TuP4
Barium Adsorption and De-wetting on W(112)

Tuesday, October 22, 2019, 6:30 pm, Room Union Station B

Session: Surface Science Poster Session
Presenter: Michael Mroz, Ohio University
Authors: V. Mroz, Ohio University
S.A. Tenney, Brookhaven National Laboratory
C. Eads, Brookhaven National Laboratory
E. Kordesch, Ohio University
Correspondent: Click to Email
The tungsten (112) surface has been observed with adsorbed barium in emission microscopy. The barium metal is deposited from a filament filled with a piece of metallic barium. When the barium layer on the W(112) surface is heated, the barium de-wets, forming a "wetting layer" and droplets of barium. The de-wetting is solid-solid de-wetting, because the rupture of the film into droplets occurs at about 1/3 of the barium melting temperature (727 C). At low coverage, about 20 nm barium, the droplets are sparse, and the wetting layer uses most of the available barium. Two 2x1 domains and weak centered 2x2 low energy electron diffraction (LEED) pattern are observed. At high coverage, about 200 nm, in addition to the wetting layer, and a dense coverage of droplets ( 250 nm diameter), there are also larger scale networks of barium drops spread over micron scale distances.