AVS 46th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS-TuP

Paper SS-TuP3
Nucleation and Growth of Faceted Features on the Platinum Covered W(111) Surface

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: K. Pelhos, Rutgers, The State University of New Jersey
Authors: K. Pelhos, Rutgers, The State University of New Jersey
J.B. Hannon, Sandia National Laboratories
G.L. Kellogg, Sandia National Laboratories
T.E. Madey, Rutgers, The State University of New Jersey
Correspondent: Click to Email
Low energy electron microscopy (LEEM) and scanning tunneling microscopy (STM) have been used to investigate the faceting of W(111) as induced by Pt. The atomically rough W(111) surface, when fully covered with a complete physical monolayer (1.7 x 10@super 15@ atoms/cm@super 2@) film of Pt and annealed to temperatures higher than ~750 K, experiences a significant morphological restructuring: the initially planar surface undergoes a faceting transition and forms three-sided pyramids with {211} faces. LEEM investigations show that when Pt is dosed onto the heated surface, the transition from planar to faceted structure proceeds through the nucleation and growth of spatially separated faceted regions starting at 2/3 physical monolayers coverage. STM reveals the atomic structure of the partially faceted surface, with large planar regions, dotted by clusters of pyramids of various sizes. On the other hand, when the initially planar sample is first completely covered with a physical monolayer of Pt and gradually heated, LEEM does not show any spatial separation in the faceting transition. STM observations of the initial stages of this transition show a continuous uniform roughening of the surface towards the faceted phase.