Abstract
The properties of thin films are controlled by the Quantum Size Effect in the films. For Pb films, the thickness dependence of thermal stability temperature exhibits bilayer oscillation modulated by a 9 ML beating pattern. The oscillation and beating phenomena are influenced by the phase shift of Quantum Well States at the interfaces of the films. We prepared uniform 2D Pb films on Ge(100), which grow layer by layer. By Angle-Resolved Photoemission Spectroscopy(ARPES) we obtained the thickness dependence of thermal stability temperature of Pb films, and the results are fitted by a model based on Friedel oscillations .Finally, we made a systematical comparison between Pb/Ge(100) and Pb/Ge(111) for the thermal stability to study the influence from the substrate.