AVS 51st International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP27
Growth Studies of Thin Pt Films on the Cu(100) Surface by CAICISS, LEED and XPS

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: M. Walker, University of Warwick, UK
Authors: M. Walker, University of Warwick, UK
C.R. Parkinson, University of Warwick, UK
C.F. McConville, University of Warwick, UK
Correspondent: Click to Email
The formation of a surface alloy upon room temperature deposition of Pt on the Cu(100) surface is observed by co-axial impact collission ion scattering spectrscopy (CAICISS), low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). Simulations of the CAICISS results are given to support the proposed alloy structures from Pt coverages of 0.25 ML upwards, with comparisons between layer-by-layer, alloy and Pt surface cluster models. With increasing Pt coverage the surface region becomes Pt rich, with a small Pt overlayer observed at a Pt coverage of 2.35 ML and above. This indicates the onset of layer-by-layer growth of a pure Pt film. LEED observations indicate that this film is disordered. The effects of annealing at temperatures up to 600 °C are also shown for samples with Pt coverages of 0.25 ML and 2.75 ML. CAICISS and XPS clearly demonstrate the penetration of Pt in to the Cu substrate upon annealing. For Pt coverages greater than 2.35 ML, annealing at 300 °C causes Pt to penetrate down to the fourth and fifth layers of the substrate, forming a CuPt surface layer and Cu@sub2@Pt sub-surface layers. For Pt coverages of ~ 0.25 ML, annealing at 200 °C resulted in a small amount of Pt migrating towards the bulk. After annealing at 300 °C the sample contained approximately 7% Pt in each of the top three layers of the sample and small Pt concentrations in the fourth and fifth layers. Annealing at 600 °C results in the onset of significant migration in to the substrate in both cases.