TY - JOUR
T1 - A multitechnique surface science examination of Sn deposition on Pt(100)
AU - Paffett, Mark T.
AU - Logan, A. David
AU - Simonson, R. Joseph
AU - Koel, Bruce E.
N1 - Funding Information:
Support from the Department of Energy through the Morgantown Energy Technology Center is gratefully acknowledged by M.T.P. B.E.K. acknowledges the support of this work by the Department of Energy, Office of Basic Energy Sciences, Chemical Sciences Division.
PY - 1991/7/2
Y1 - 1991/7/2
N2 - Interfaces prepared by vapor deposition of Sn onto Pt(100) surfaces have been examined using the following techniques: Auger electron and X-ray photoelectron spectroscopy (AES and XPS), low-energy electron diffraction (LEED), and low-energy ion surface scattering (LEISS) with Ne+ ions. Tin deposition was conducted at 320 and 600 K, and the surface composition and order was examined as a function of further annealing to 1200 K. The AES uptake plots (signal versus deposition time) indicate that the Sn growth mode can be described by a layer-by-layer process only up to one adayer at 320 K. Some evidence of 3D growth is inferred from LEED and LEISS data for higher Sn coverages. For deposition at 600 K, AES data indicate significant interdiffusion and surface alloy formation. LEED observations (recorded at a substrate temperature of 320 K) show that the characteristic hexagonal Pt(100) reconstruction disappears with Sn exposures of 4.6 × 1014 atoms cm2 (θSn = 0.35 monolayer (ML)). Further Sn deposition results in a c(2 × 2) LEED pattern starting at a coverage of slightly above 0.5 ML. The c(2 × 2) LEED pattern becomes progressively more diffuse with increasing Sn exposure with eventual loss of all LEED features above 2.2 ML. Annealing experiments with various precoverages of Sn on Pt(100) are also described by AES, LEED, and LEISS results. For specific Sn precoverages and annealing conditions, c(2 × 2), p(3√2 × √2)R45°, and a combination of the two LEED patterns are observed. These ordered LEED patterns are suggested to arise from ordered PtSn surface alloys. In addition, the chemisorption of CO and O2 at the ordered annealed Sn/Pt(100) surfaces was also examined using thermal desorption mass spectroscopy (TDMS), AES, and LEED.
AB - Interfaces prepared by vapor deposition of Sn onto Pt(100) surfaces have been examined using the following techniques: Auger electron and X-ray photoelectron spectroscopy (AES and XPS), low-energy electron diffraction (LEED), and low-energy ion surface scattering (LEISS) with Ne+ ions. Tin deposition was conducted at 320 and 600 K, and the surface composition and order was examined as a function of further annealing to 1200 K. The AES uptake plots (signal versus deposition time) indicate that the Sn growth mode can be described by a layer-by-layer process only up to one adayer at 320 K. Some evidence of 3D growth is inferred from LEED and LEISS data for higher Sn coverages. For deposition at 600 K, AES data indicate significant interdiffusion and surface alloy formation. LEED observations (recorded at a substrate temperature of 320 K) show that the characteristic hexagonal Pt(100) reconstruction disappears with Sn exposures of 4.6 × 1014 atoms cm2 (θSn = 0.35 monolayer (ML)). Further Sn deposition results in a c(2 × 2) LEED pattern starting at a coverage of slightly above 0.5 ML. The c(2 × 2) LEED pattern becomes progressively more diffuse with increasing Sn exposure with eventual loss of all LEED features above 2.2 ML. Annealing experiments with various precoverages of Sn on Pt(100) are also described by AES, LEED, and LEISS results. For specific Sn precoverages and annealing conditions, c(2 × 2), p(3√2 × √2)R45°, and a combination of the two LEED patterns are observed. These ordered LEED patterns are suggested to arise from ordered PtSn surface alloys. In addition, the chemisorption of CO and O2 at the ordered annealed Sn/Pt(100) surfaces was also examined using thermal desorption mass spectroscopy (TDMS), AES, and LEED.
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U2 - 10.1016/0039-6028(91)90715-5
DO - 10.1016/0039-6028(91)90715-5
M3 - Article
AN - SCOPUS:0026413935
SN - 0039-6028
VL - 250
SP - 123
EP - 138
JO - Surface Science
JF - Surface Science
IS - 1-3
ER -