Thin film growth of Pt on Rh(1 0 0): a LEIS study

Low energy Li+ ion scattering has been used to study ultrathin Pt films deposited at room temperature on Rh(1 0 0). The Pt atoms are seen to adsorb into the top layer of the Rh(1 0 0) substrate residing in face-centered-cubic (fcc) sites thereby forming a surface alloy. Through the use of specific scattering geometries to isolate first and second layer contributions, Pt was seen to grow in a layer-by-layer fashion for at least the first two layers. This was confirmed by analysing the incident angle dependence associated with shadowing effects as a function of growth. Finally, the thermal stability of the deposited Pt was investigated. The Pt was seen to diffuse into the bulk of the Rh(1 0 0) crystal at approximately 700 K. We believe this is due to C contamination as a consequence of the heating process.