Surface modification of Pt(111) by Sn adatoms: Evidence for the formation of ordered overlayers and surface alloys

摘要: Abstract Vapor deposition of Sn onto Pt(111) in ultrahigh vacuum (UHV) has been examined by Auger electron spectroscopy (AES), X-ray photoelectron (XPS), low energy diffraction (LEED) and ion (Ne + ) scattering (LEISS). The AES uptake plots for depositions at substrate temperatures between 140 400 K indicate a uniform layer growth up to exposure 9.1 × 10 14 atoms cm -2 . LEED data taken simultaneously the successive appearance following patterns submonolayer coverages: (√3 √3) R 30° followed c(4 2). Simple overlayer real space structures are suggested these ordered overlayers. For exposures greater than temperatures, nonlinear an increasingly diffuse pattern observed. above 450 K, Pt-Sn alloy formation is strongly from LEISS data. Annealing Sn-Pt interface 1000 K. produces (as judged LEED) surfaces. Evidence also inferred variable incidence angle Real models consistent with proposed.