AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuA

Paper SS2-TuA5
Synthesis and Characterization of an Ordered Ge Overlayer and Pt@sub 2@Ge Compound on Pt(100)

Tuesday, November 4, 2003, 3:20 pm, Room 327

Session: Surfaces and Interfaces of Semiconductors and Compound Materials
Presenter: T. Matsumoto, University of Southern California
Authors: T. Matsumoto, University of Southern California
M. Batzill, University of Southern California
C. Ho, University of Southern California
B.E. Koel, University of Southern California
Correspondent: Click to Email
A c(2 x 2)-Ge overlayer and Pt@sub 2@Ge compound were formed by Ge deposition and annealing to 600 K on Pt(100) and characterized by Na@super +@-ALISS, XPD, LEED and STM. STM topographs and LEED patterns indicate a c(2 x 2) structure after 0.5-ML Ge deposition or 1.5-ML Ge deposition with annealing to 600 K. ALISS was used to unambigously distinguish between the c(2 x 2) overlayer and surface alloy phases. This technique showed Ge-scattering angular peaks assigned to a large separation of Ge atoms along the [011] azimuth corresponding to a c(2 x 2)-Ge overlayer after 0.5-ML Ge deposition. Following 1.5-ML Ge deposition and annealing to 600 K, a new Ge-scattering angular peak appeared that was assigned to scattering from third-layer Ge atoms, however, no second-layer Ge scattering peak was observed. This structure is consistent with a body-centered tetragonal Pt@sub 2@Ge layer surface alloy which has alternating c(2 x 2) Ge-Pt and (1 x 1)-Pt(100) layers. XPD results also support this structural model. Annealing these surfaces to 900 and 1200 K resulted in partial dissolution of Ge atoms deeply into the bulk. XPS was also used to characterize the chemical nature of Ge and Pt at these surfaces.