Thin film growth of Pt on Cu(111) : A LEIS study

Low energy Li⁺ ion scattering with a combination of LEED has been used to study thin Pt films on Cu(111) deposited at room temperature (≤50°C) and subsequently heated. At room temperature, Pt grew epitaxially on Cu(111) in the regular fee stacking sequence for a thickness of at least five monolayers. For the annealing temperature of ∼300°C, Pt-Cu intermixing was observed, forming a metastable Cu₃Pt surface alloy. Analysis of the surface layers was made by analysing the incident angle dependence associated with shadowing effects and comparison to the results obtained from a bulk Cu₃Pt(111) single crystal, revealing that the alloy is Cu₃Pt(111) phase over at least three atomic layers. Neither CuPt(111) nor CuPt₃(111) surface phase has been evidenced in this study.